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Postresp

1. SESAM Postresp Program version 62 15 DEC 207 3 13 Table 3 1 NO RESPONSE VARIABLE WAVE SPECTRUM HEADING SPREADING SWAY FRPMI 0 COS2 31 YAW FRPMI 0 COS2 YAW FRPMI 0 COS2 36 YAW FRPM3 90 COS2 As for response spectra Postresp automatically generates identification numbers for short term responses The numbering system is illustrated Input all rigid motions 2 headings 0 and 90 degrees wave spreading function COS2 Table 3 2 NO RESPONSE VARIABLE HEADING SPREADING 1 HEAVE 0 COS2 2 HEAVE 90 COS2 3 PITCH 0 COS2 4 PITCH 90 COS2 5 ROLL 0 COS2 6 ROLL 90 COS2 7 SURGE 0 COS2 8 SURGE 90 COS2 9 SVVAY 0 COS2 10 SVVAY 90 COS2 11 YAW 0 COS2 12 YAW 90 COS2 Postresp SESAM 3 14 15 DEC 2007 Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 4 1 4 EXECUTION OF POSTRESP Postresp accesses the Hydrodynamic Results Interface File G file generated by the wave load programs of Sesam This file may also be generated from a structural analysis Results Interface File by the Sesam pro gram Prepost The start up of Postresp is described in Section 4 2 This section also describes the files used by Postresp The program requirements and limitations are described in Section 4 3 and Section 4 4 More details on use of graphics mode and line mode are given in Section 4 5
2. WAVE SPREADING FUNCTION USER SPECIFIE Tj Jg WAVE STATISTICS tia WAVE STATISTICS ISSC SCATTER DIAGRAM WAVE STATISTICS NORDENSTRO WAVE STATISTICS SCATTER DIAGRAM Program version 6 2 15 DEC 2007 HANGE WAVE STATISTICS REATE REATE LONG TERM FATIGUE REATE LONG TERM RESPONSE REATE RESPONSE CO SPECTRUM REATE RESPONSE SPECTRU REATE RESPONSE VARIABLE REATE RESPONSE VARIABLE COMBINED MOTION REATE RESPONSE VARIABLE FIRST DERIVATED REATE RESPONSE VARIABLE GENERAL COMBINATION REATE RESPONSE VARIABLE SECOND DERIVATED REATE RESPONSE VARIABLE USER SPECIFIED REATE SHORT TERM RESPONSE REATE SN CURVE REATE SPECIFIC POINT REATE SPEED REDUCTION CURVE REATE WAVE SPECTRU REATE WAVE SPECTRUM 2D USER SPECIFIED REATE WAVE SPECTRUM GENERAL GAMMA REATE WAVE SPECTRUM ISSC REATE WAVE SPECTRUM JONSWAP REATE WAVE SPECTRUM OCHI HUBBLE REATE WAVE SPECTRUM PIERSON MOSKOWITZ REATE WAVE SPECTRUM TORSETHAUGEN REATE WAVE SPECTRUM USER SPECIFIED Ri E S 4 e Ri E Lr Lr WORKABILITY ANALYSIS CONSTANTS eal FRI ENCY RANGE Gal Le G H H ea Lr P NTATION OPTION Lr R LONG TERM PROBABILITY R tA RI RN PERIOD SPEED REDUCTION Lr R STRUCTURE ORIENTATION LONG TERM FATIGU e n1 R E LONG TERM RESPONSE RESPONSE CO SPECTRUM ae ESPONSE SPE
3. tv p tv h0 hc h0 gamma ntz distr nsd VVAVE STATISTICS name txt NORDENSTROM at bt cond nhs hsmax ah bh steep PURPOSE To create wave statistics models for use in the long term response calculation The wave statistics model describes the sea state conditions during a long term period and consists of mainly Tz and Hs values and their probability of occurrence By this command the wave statistics model will be according to Norden strom s theory PARAMETERS name Name of the wave statistics txt Descriptive text for the model tv Visual wave period Tv p tv Probability that Tv falls within the interval represented by the class midpoint ho Weibull parameter for the distribution function describing the probability that the visual wave height does not exceed Hv hc h0 Weibull parameter gamma Weibull parameter ntz Number of zero upcrossing periods which will be used in the long term calculation distr Distribution function of the zero upcrossing periods Tz Either NORMAL or LOG NOR MAL nsd Number of standard deviations by which the range of Tz is extended at either end at Parameter defining the relationship between zero upcrossing period Tz and visual wave pe riod Tv bt Parameter defining the relationship between Tz and Tv cond Conditional coefficient of variation of Tz nhs Number of significant wave heights to be used in the calculation of the long ter
4. Program version 6 2 15 DEC 2007 A 3 FRPM11 which corresponds to TZ 10 0 seconds There will be generated 12 response spectra CREATE RESPONSE SPECTRUM HEAVE PITCH 0 45 90 FRPM11 NONE CREATE RESPONSE SPECTRUM HEAVE PITCH 0 45 90 FRPM11 COS2 Create a short term response for the response variables HEAVE and PITCH for the main wave directions 0 45 and 90 degrees and for both long and short crested sea The wave spectrum type used is Pierson Moskowitz with a Tz range from 5 0 to 15 0 seconds There o AP AP do oe oe wi be generated 12 short term responses CREATE SHORT TERM RESPONSE HEAVE PITCH 0 45 90 FRPM 1 21 NONE CREATE SHORT TERM RESPONSE HEAVE PITCH 0 45 90 FRPM 1 21 COS2 Assign probability and wave statistic model to each wave direction to be used in long term response o o9 do oe ASSIGN WAVE DIRECTION PROBABILITY 0 0 0 125 ASSIGN WAVE DIRECTION PROBABILITY 45 0 0 25 ASSIGN WAVE DIRECTION PROBABILITY 90 0 0 25 ASSIGN WAVE DIRECTION PROBABILITY 135 0 0 25 ASSIGN WAVE DIRECTION PROBABILITY 180 0 0 125 oo ASSIGN WAV ASSIGN WAV STATISTICS 0 0 NOR1 STATISTICS 45 0 NOR1 ASSIGN NAVE STATISTICS 90 0 NOR1 ASSIGN WAVE STATISTICS 135 0 NOR1 ASSIGN WAVE STATISTICS 180 0 NOR1 EE GE rj ASSIGN WAVE SPREADING FUNCTION NOR1
5. PURPOSE To delete user created response variables It is not possible to delete any response variables read from the Results Interface File PARAMETERS name User given name of the response variable Postresp SESAM 5 78 15 DEC 2007 Program version 6 2 DELETE SHORT TERM RESPONSE SHORT TERM RESPONSE number PURPOSE To delete a generated short term response PARAMETERS number Reference number of the short term response This reference number is generated by the pro gram and may be examined by the PRINT OVERVIEW SHORT TERM RESPONSE com mand SESAM Program version 6 2 15 DEC 2007 DELETE SN CURVE SN CURVE namet PURPOSE To delete a user specified SN curve PARAMETERS name Name of the user specified SN curve Postresp 5 79 Postresp 5 80 15 DEC 2007 DELETE SPECIFIC POINT SPECIFIC POINT name PURPOSE To delete a specific point PARAMETERS name Name of the point SESAM Program version 6 2 SESAM Program version 6 2 15 DEC 2007 DELETE SPEED REDUCTION DATA SPEED REDUCTION DATA namet PURPOSE To delete a speed reduction curve PARAMETERS name Name of the curve Postresp 5 81 Postresp 5 82 15 DEC 2007 DELETE WAVE SPECTRUM WAVE SPECTRUM namet PURPOSE To delete a wave spectrum PARAMETERS name Name of the spectrum SESAM Program versio
6. Table B 1 T f Ay Ho H Ho m 4 5 0 1190 1 0 0 25 0 63 6 5 0 3455 1 25 0 95 0 85 8 5 0 3586 1 10 2 05 1 13 10 5 0 1385 0 75 3 30 1 56 12 5 0 0291 0 35 5 00 1 82 14 5 0 0056 0 20 6 15 2 02 16 5 0 0010 0 00 6 30 1 86 18 5 0 0028 0 35 2 00 0 85 Parameters of the Weibull distributions of visual wave heights on the North Sea 7 in secs Hg and H in meters Ref 1 Table B 2 T SH Ho H Hy m 3 0 0 0335 0 0 72 3 06 4 0 0 0496 0 0 89 2 27 5 0 0 1517 0 0 80 1 15 6 0 0 4319 0 1 25 1 54 SESAM Postresp Program version 62 15 DEC207 Bel Table B 2 7 0 0 1785 0 2 03 2 27 8 0 0 1415 0 2 40 2 63 9 0 0 0100 0 2 40 2 17 10 0 0 0033 0 2 95 2 90 B3 TRANSFER FUNCTIONS B 3 1 Basic Transfer Functions A transfer function describes the response of a structure in regular sinusoidal waves over a range of frequen cies The amplitude of the response is normalized with respect to the amplitude of the wave A representa tion in the complex plane is used in order to carry phase information between the response variable and the incoming wave Once the complex transfer function H for response variable x is known the time dependent response varia ble can be determined form R t E Re H e 7 B 59 where is the amplitude of the incoming wave is the frequency of the incoming wave and t denotes the time In terms of phase angle and amplit
7. PURPOSE The main purpose is to create combinations of sectional force response variables However the command may be used to combined any response variables where each component is added together with a scaling factor PARAMETERS name Name of the response variable txt Descriptive text of the response variable resp Name of the response variable fact Multiplication factor for the corresponding response variable All selected response variables will then be added together EXAMPLES CREATE RESPONSE VARIABLE AG2 Air gap GENERAL COMBINATION ONLY MOT1 1 0 elev2 14 0 SESAM Postresp Program version 6 2 15 DEC 2007 5 37 CREATE RESPONSE VARIABLE SECOND DERIVATED RESPONSE VARIABLE name txt SECOND DERIVATED resp PURPOSE To create a the second derivative of a selected response variable The response variable will be created by multiplying each amplitude by its squared angular frequency i e the real and imaginary part is multiplied by 2 PARAMETERS name Name of the response variable txt Descriptive text of the response variable resp Name of the response variable Postresp SESAM 5 38 15 DEC 2007 Program version 6 2 CREATE RESPONSE VARIABLE USER SPECIFIED RESPONSE VARIABLE name txt USER SPECIFIED depth dir freq real imag SPEED INCLUDED depth froude dir freq real imag
8. H o amp S o d o B 73 while the compound response spectra are defined by n 2 Sreo Salo 8 fla do B 74 n 2 When creating each individual response spectrum using a JONSWAP Pierson Moskowitz or user defined spectrum the transfer function selected is divided linearly without any smoothing in 201 frequencies corre sponding to which the wave spectrum is given The numerical integration for calculating the spectral param eters is then performed in these 201 points with normal trapeze integration within the frequency range for which the transfer function and wave spectrum is given No extrapolation or asymptotic approaches are used Using a general gamma spectrum the response spectrum itself is not calculated only the spectral parame ters are calculated analytically Postresp SESAM B 18 15 DEC 2007 Program version 6 2 B 4 3 Response Covariance The covariance is a measure of the degree of inter relationship between responses Considering the response variables x and x the covariance Cov xy x5 is given by n 2 qo Cov x x 1 2 f H 9H o S SCof a dodo B 75 where H denotes the complex conjugate of the complex transfer function H The normalized covariance or correlation coefficient is defined as Cov x x5 5 0 B 76 where 6 y and o are the standard deviation values of the individual response variables x and x If p is large and positive i e approaching 1 the v
9. Wave Spreading Function Wave Statistics Workability Analysis Figure C 43 PRINT MATRIX pull down menu Postresp SESAM C 38 15 DEC 2007 Program version 6 2 ME POSTRESP 6 2 04 Response Variable Second Order Statistics Short Term Response Short Term Statistics Short Term Fatigue Specific Point Wave Spectrum Wave Spreading Function Wave Statistics Workability Analysis Figure C 44 PRINT OVERVIEW pull down menu SESAM Postresp Program version 6 2 15 DEC 20074 C 39 ME Print Long Term Fatigue Type of Long term Fatigue GR i Based on Rayleigh for each sea state Based on Longterm Weibull Response Variable Name Duration Include Exclude Overwrite Insert before Clear Help Apply Cancel ME Print Long Term Response x ME Print SN curve Type of Long term Response Response Variable SN curve Name Response Variable Name Cancel Apply Cancel Figure C 45 PRINT LONG TERM FATIGUE Rayleigh LONG TERM RESPONSE SN CURVE Postresp SESAM C 40 15 DEC 2007 Program version 6 2 ME Print Long Term Fatigue Type of Long term Fatigue Rayleigh Based on Rayleigh for each sea state Weibull Based on Lonaterm Weibull Response Variable Name SN curve HEAVE SURGE SWAY Duration Duration Include Exclude Overwrite Insert before Clear Help Cancel EE Print Matrix Added Mass x f mm Print Matrix Added Mas
10. EXAMPLES CREATE WAVE STATISTICS WS3 Scatter diagram for SESAM field SCATTER DIAGRAM PROBABILITY 50 6 0 oooo Pou r 6 s 8 OO O O1 OF OY TO c SESAM Postresp Program version 6 2 15 DEC 2007 5 61 CREATE WORKABILITY ANALYSIS WORKABILITY ANALYSIS name tx ec resp rmsall dir PURPOSE To create a workability analysis for a set of response variables and selected wave directions For each wave direction used a scatter diagram must be assigned The allowable response level double amplitude speci fied for each response variable is compared with the significant response calculated in each cell of the scat ter diagram If the significant response is less than the allowable level the probability or number of occurrences for this cell is added to a total sum The total contribution of this is a measurement of the up time period for the vessel in the given long term condition PARAMETERS name Name of the workabihty analysis txt Descriptive text for the analysis resp Name of the response variable included rmsall Allowable response level double amplitude dir Main wave direction Wild card specification is available Postresp SESAM 5 62 15 DEC 2007 Program version 6 2 DEFINE CONSTANT FREQUENCY RANGE LONG TERM PROBABILITY DEFINE PRESENTATION OPTION RETURN PERIOD SPEED REDUCTION STRUCTURE ORIENTATION
11. File name prefix Name of the Hydrodynamic Results Interface File or WAMIT files Postresp SESAM 5 106 15 DEC 2007 Program version 6 2 PLOT PLOT PURPOSE Plot last display on hard copy device The previous commands and selection are used in the plotting The user may change some presentation options like the x axis required colour setting grid on off etc This command is not available from the menubar in graphics mode Use FILE PLOT instead SESAM Postresp Program version 6 2 15 DEC 2007 5 107 PRINT DATA SET LIMITATIONS LONG TERM FATIGUE LONG TERM RESPONSE MATRIX OVERVIEW RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE SECOND ORDER STATISTICS SHORT TERM FATIGUE SHORT TERM RESPONSE SHORT TERM STATISTICS SN CURVE SPECIFIC POINT SPEED REDUCTION WAVE SPECTRUM WAVE SPREADING FUNCTION WAVE STATISTICS WORKABILITY ANALYSIS PRINT PURPOSE This is used to print selected information to the computer screen or on a print file Most of the subcommands available are the same as for the corresponding CREATE subcommands In addi tion the user is offered several subcommands for printing a global or object dependent overview and pro gram status information Postresp SESAM 5 108 15 DEC 2007 Program version 6 2 PRINT DATA SET DATA SET PURPOSE This command gives a list of available bodies or data se
12. PRINT SHORT TERM RESPONSE PRINT ERM STATISTICS RAYLEIGH SEA STATE DURATION 3600 10800 108000 12 37 8 9 4 5 6 10 11 12 RINT LONG TERM RESPONSE RESPONSE Plot sequence Before each plot a user defined text is given to describe the plot in a proper way wave spectrum named FRPM11 wave spreading function named COS2 response variables HEAVE PITCH ADISZSP and SPLITSP with headings 0 45 and 90 degrees in each plot HEAVE and PITCH are given for angular frequency period and wave length a response spectra created a short term responses created long term response for HEAVE and PITCH with headings 0 45 90 degrees and all headings included The plots are given both as a function of LOG Q and wave headings J n m o A El q VARIABLE HEAVE de AP de do AP AP o AP o P AP o do oe SET DISPLAY DEVICE X WINDOW SET DISPLAY DESTINATION FILE SET PLOT FORMAT POSTSCRIPT oo SET TITLE Nave spectrum used in response spectra EN VO E DISPLAY WAVE SPECTRUM FRPM11 SET TITLE Nave spreading used for short crested sea vs vow n x SESAM Postresp Program version 6 2 15 DEC 2007 A 5 DISPLAY WAVE SPREADING FUNCTION COS2 45 Response variables as functions of angular frequency default
13. PURPOSE The define command is used to define different global variables and execution directives SESAM Program version 6 2 15 DEC 2007 DEFINE CONSTANT GRAVITY grav WATER DENSITY rho CONSTANT HS TOLERANCE HsTol TZ TOLERANCE TzTol FREQUENCY TOLERANCE FrqTol PURPOSE To define global constants for use in the program PARAMETERS grav Gravity default 9 81 m s rho Water density default 1025 kg m HsTol Numerical tolerance between different Hs values TzTol Numerical tolerance between different Tz values FrqTol Numerical tolerance between different angular frequencies Postresp 5 63 Postresp SESAM 5 64 15 DEC 2007 Program version 6 2 DEFINE FREQUENCY RANGE FREQUENCY RANGE low freq upp freq PURPOSE To define the frequency range within which the wave spectra will be established By default the range will be as given on the Results Interface File read in If no Interface file is used this has to be specified by the user PARAMETERS low freq Lower angular frequency upp freq Upper angular frequency SESAM Postresp Program version 6 2 15 DEC 2007 5 65 DEFINE LONG TERM PROBABILITY LONG TERM PROBABILITY log Q PURPOSE To define long term probability level for which the value of x is requested for the long term distribution of x PARAMETERS log Q The probability given as an absolute integer expone
14. Postresp C 43 Second Direction Cancel Apply Cancel Figure C 49 PRINT RESPONSE VARIABLE SHORT TERM RESPONSE SPECIFIC POINT SPEED REDUCTION Postresp SESAM C 44 15 DEC 2007 Program version 6 2 EE Print Short Term Statistics Distribution Input type Rayleigh C Rice Probability of Exceedance C Sea State Duration Response Spectrum Response level Include Exclude Overwrite Insert before Clear Help Apply Cancel Il Print Wave Statistics Es L Print Workability Analysis Name of Workability Analysis OK Apply Cancel Cancel Figure C 50 PRINT SHORT TERM STATISTICS WAVE STATISTICS WORKABILITY ANAL YSIS SESAM Postresp Program version 6 2 15 DEC 20074 C 45 ME Print Short Term Fatigue Response Spectrum SN curve Duration Include Exclude Overwrite Insert before Clear Help Cancel ME Print Wave Spectrum Print Wave Spreading Function x Spectrum Function Name Spectrum Statistics cos2 cos4 C Dump Spectrum OK Apply Cancel OK Apply Cancel Figure C 51 PRINT SHORT TERM FATIGUE WAVE SPECTRUM WAVE SPREADING FUNC TION Postresp SESAM C 46 15 DEC 2007 Program version 6 2 C10 RUN Menu ME POSTRESP 6 2 04 2 EE EEG Figure C 52 RUN pulldown menu ME Run Equation Solver Figure C 53 RUN EQUATION SOLVER Specific Frequency SESAM Postresp Program version 6 2 15 DEC 20074 C 47 NE Run Equation
15. RESPONSE LEVEL PROBABILITY OF EXCEEDANCE SEA STATE DURATION Rayleigh distribution function will be used on the wave peaks Rice distribution function will be used on the wave peaks with the spreading parameter epsilon as in the response spectrum chosen Response level given for which the probability of exceedance is requested Probability of exceedance is given the response level referring to this will be printed User given sea state duration The program will print total number of zero upcrossings the probability of exceedance and the corresponding response level level Response level for which the probability of exceedance is re quested prob Probability of exceedance given for which the response level is requested durat Sea state duration in seconds spec Response spectrum reference number for which the short term statistics is to be performed on EXAMPLES PRINT SHORT TERM STATISTICS RAYLEIGH SEA STATE DURATION 10800 123 PRINT SHORT TERM STATISTICS RAYLEIGH RESPONSE LEVEL 6 0 123 SESAM Program version 6 2 PRINT SHORT T ERM STATISTICS RAYL 15 DEC 2007 EIGH PROBABILITY OF I EXCE EDANCE Postresp 5 123 0 0001 1 2 3 Postresp 5 124 15 DEC 2007 PRINT SN CURVE SN CURVE name PURPOSE To print data related to an SN curve PARAMETERS name Name of the SN curve S
16. The dump is not available for a response spectrum calculated with a general gamma spectrum PARAMETERS number Reference number of the response spectrum DUMP SPECTRUM A response spectrum for given reference number will be dumped i e spectrum or dinates for 201 frequencies will be printed SESAM Postresp Program version 6 2 15 DEC 2007 5 117 PRINT RESPONSE VARIABLE naml dir SECOND ORDER nam2 dirl dir2 RESPONSE VARIABLE PURPOSE To print first or second order response variables PARAMETERS SECOND ORDER Second order response variables will be printed naml Name of the first order response variable dir VVave direction for the first order response variable nam2 Name of the second order response variable dirl First wave direction for the second order response variable dir2 Second wave direction for the second order response variable Postresp 5 118 SESAM 15 DEC 2007 Program version 6 2 PRINT SECOND ORDER STATISTICS DIFFERENCE FIRST ORDER INCLUDED SECOND ORDER STATISTICS SUM SECOND ORDER ONLY ALL option spec sprea dir prob PURPOSE To calculate and print the response statistics for pure second order or combined first and second order responses The print table provides the mean standard deviation skewness kurtosis and maximum and minimum extreme levels for a specified set of probabilities PARAME
17. WAVE SPREADING FUNCTION name txt PURPOSE To change a wave energy spreading function Postresp 5 24 15 DEC 2007 SESAM Program version 6 2 CHANGE WAVE SPREADING FUNCTION COSINE POWER WAVE SPREADING FUNCTION name txt COSINE POWER power PURPOSE To change energy spreading for elementary wave directions by changing the power of a defined cosine func tion PARAMETERS name txt power Name of the spreading function Descriptive text of the spreading function Power of the cosine function given as an integer value EXAMPLES CHANGI E WAVI E SPRI EADING FUNCTION COS COSINI E SPRI EADING COSINI E POWI ER 3 SESAM Postresp Program version 6 2 15 DEC 2007 5 25 CHANGE WAVE SPREADING FUNCTION USER SPECIFIED WAVE SPREADING FUNCTION name tx ec USER SPECIFIED dir fact PURPOSE To change energy spreading for elementary wave directions with user defined weights on each direction The sum does not need to be equal to 1 since the program will normalize the weights when using the spread ing function PARAMETERS name Name of the spreading function txt Descriptive text of the spreading function dir Relative direction to the main wave direction in use The range is if spanning over 180 de grees from 90 degrees to 90 degrees fac
18. wave length and period o do AP oe SET TITLE Transfer function for first order motion E ES It Response variables as functions of angular frequency o oP oe DISPLAY RESPONSE VARIABLE HEAVE 0 45 90 DISPLAY RESPONSE VARIABLE PITCH 0 45 90 DISPLAY RESPONSE VARIABLE ADISZSP 0 45 90 DISPLAY RESPONSE VARIABLE SPLITSP 0 45 90 Response variable as function of wave length o do oe DEFINE PRESENTATION OPTION ABSCISSA AXIS WAVE LENGTH DISPLAY RESPONSE VARIABLE HEAVE 0 45 90 DISPLAY RESPONSE VARIABLE PITCH 0 45 90 Gl Response variable as function of period o oP oe DEFINE PRESENTATION OPTION ABSCISSA AXIS PERIOD DISPLAY RESPONSE VARIABLE HEAVE 0 45 90 DISPLAY RESPONSE VARIABLE PITCH 0 45 90 Reset abscissa axis to angular frequency do oe DEFINE 1j ID ESENTATION OPTION ABSCISSA AXIS ANGULAR FREQUENCY oe n ET TITLE Response spectra for HEAVE long crested sea TS ARS EE DISPLAY RESPONSE SPECTRUM 1 234 oo n ET TITLE Response spectra for HEAVE short crested sea Sod Mog wu DISPLAY RESPONSE SPECTRUM 789 oo n ET TITLE Response spectra for PITCH long crested sea hd IK let DISPLAY RESPONSE SPECTRUM 456 oe n ET TITLE Response spectra for PITCH short crested sea
19. 4 5 5 Selecting several Alternatives from a List In e g the PRINT RESPONSE VARIABLE command a scrollable list of all response variables is pre sented Any number of response variables can be selected from this list for print Selected values are marked by highlighting Print Response Variable x Order Variable Name Wave Direction First Order C Second Order Figure 4 11 The Print Response Variable dialogue box The basic way to select values is to click on a value and then drag the mouse through the list All values that the mouse pointer is dragged through are selected and any previously selected value becomes unselected To modify an existing selection hold the Control key down while clicking in the list or dragging the mouse pointer through the list All items that are clicked on while the Control key is held will reverse their selec tion status 4 5 6 Entering a Vector or Matrix of Values In many cases a vector or matrix of values must be input Examples are entering return periods or creating a general combination of response variables Postresp 4 18 15 DEC 2007 The Create Response Variable dialogue box Create Response Variable xi Name ussm2 Forward speed or not Response Type User Specified C Speed included Variable Contents Wave Direction pb Wave Frequency Include Exclude Overwrite Insert before Clear Help App Cancel Figure 4 12 The Create Response Variable dialogue
20. A 22 15 DEC 2007 Program version 6 2 SESAM POSTRESP 6 1 01 26 NOV 1993 Short term resp for HEAVE short crested sea Short Term Response 0 N D gt ar o c D D 2 a t D c w 44 16 Zero upcrossing period s A 7 HEAVE Dir 0 0 FRPMI FRPM21 COS2 8 HEAVE Dir 45 0 FRPM FRPM21 COS2 9 HEAVE Dir 90 0 FRPMI FRPM21 COS2 SESAM Postresp Program version 6 2 15 DEC 2007 A 23 SESAM POSTRESP 6 1 01 26 NOV 19935 Short term resp for PITCH long crested sea Short Term Response 0 N de m E 0 c i Uu D o c o c ul 14 16 Zero upcrossing period s PITCH Dir 0 0 FRPMI FRPM21 PITCH Dir 45 0 FRPM FRPM2 I PITCH Dir S0 G FRPM1 FRPM21 Postresp SESAM A 24 15 DEC 2007 Program version 6 2 SESAM POSTRESP 8 1 01 28 NOV 1993 Short term resp for PITCH short crested sea Short Term Response 0 N gt D E w 0 c D 2 o L o c Ll Zero upcrossing period s lA 10 PITCH Dir 0 0 FRPMi FRPM21 COS2 11 PITCH Dir 45 0 FRPMI FRPM21 COS2 El 12 PITCH Dir 90 0 FRPM1 FRPM21 COS2 SESAM Program version 6 2 Postresp 15 DEC 2007 A 25 SESAM POSTRESP 6 1 01 26 NOV 1993 25 Response 20 Long term response for HEAVE Long Term Response 10 Log 1G Prob Response Variable L HEAVE HEAVE El HEAVE 7 HEAVE Dir 0 0 Dir 45 0 Dir 90 0 ALL Inc Postresp SESAM A 26 15 DEC 2007 Program versio
21. DNY SESAM USER MANUAL Postresp p Postprocessor for Statistical Response Calculations DET NORSKE VERITAS SESAM User Manual Postresp Postprocessor for Statistical Response Calculations December 15th 2007 Valid from program version 6 2 Developed and marketed by DET NORSKE VERITAS DNV Software Report No 86 3315 Revision 8 December 15th 2007 Copyright 2007 Det Norske Veritas All rights reserved No part of this book may be reproduced in any form or by any means without permission in writing from the publisher Published by Det Norske Veritas Veritasveien 1 N 1322 Hovik Norway Telephone 47 67 57 99 00 Facsimile 47 67 57 72 72 E mail sales software sesam dnv com E mail support software support dnv com Website www dnvsoftware com If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas then Det Norske Veritas shall pay compensation to such person for his proved direct loss or damage However the compensation shall not exceed an amount equal to ten times the fee charged for the service in question provided that the maximum compensation shall never exceed USD 2 millions In this provision Det Norske Veritas shall mean the Foundation Det Norske Veritas as well as all its subsidiaries directors officers employees agents and any other acting on behalf of Det Norske Veritas 1 1 1 2 1 3
22. File Project Model Load Analysis Result Utility Options Help 2 gt elol 5 P ees Opened existing project R5Big SESAM Program version 6 2 Figure 4 4 Command line mode dialogue of Manager 4 2 4 Starting Postresp in Graphics Mode When started from Manager the main Postresp will be as shown in Figure 4 5 Mi POSTRESP 6 2 04 File Assign Change Create Define Delete B 7 y A Print Run EXESESIFAESCS NEW journal file created Please proceed as follows Alternative 1 Read a Hydrodynamic Response Use the command FILE Alternative 2 Define frequency range Use the command DEFINE Total probability of the scatter diagram is Total probability of the scatter diagram is Current Graphics Device WINDOWS Select Set Help Figure 4 5 The main Postresp window SESAM Postresp Program version 6 2 15 DEC 2007 4 7 When started from outside Manager with no input command file the Postresp startup window will be as shown in Figure 4 6 MM POSTRESP 6 2 04 2 Hi tele Figure 4 6 Postresp startup in graphics mode Postresp can now be operated as described in section 3 1 and 3 2 To exit the program choose the Exit option under the File menu Postresp will then close all open files and exit SESAM Program version 6 2 Postresp 4 8 15 DEC 2007 4 2 5 Starting Postresp in Line Mode on Unix A line mode session will not give access to the graphics mode capabilities The program runs
23. Postresp SESAM B 20 15 DEC 2007 Program version 6 2 We eU pe D Hy T _ D HH Tz dH dT ETE MC E qu The number of response maxima not exceeding the level x is obtained from the product of the expected number of response maxima in the sea state and the cumulative probability DSU TEA T NGHE ES N HysTJFSQ H T E T H T x SIOZ dH dT B 85 The number of response cycles not exceeding the level x in the long term is obtained by integrating the short term result over the range of sea states that may be experienced TF HS TD He N x D f UH THT dH dT B 86 Finally the long term probability of not exceeding the level x is given by dividing the number of response maxima that do not exceed this level by the total number of response maxima TF H T Ru 7 RES anar z B 87 where the total number of response maxima are simply the number of response maxima which is never exceeded N oo and the long term mean response period is obtained by dividing the long term duration by the total number of response cycles HT ap sra 1 em Rr 4s Bee A Weibull distribution may then be fitted to the numerical long term response distribution cel y e B 89 where a is referred to as the scale parameter of the distribution and m is referred to as the slope parameter of the distribution The probability of exceeding the response level x is given by OG 1 Fix B 90 The response predictio
24. Apply Cancel Figure C 30 DEFINE LONG TERM PROBABILITY PRESENTATION OPTION SPEED REDUCTION STRUCTURE ORIENTATION Postresp C 28 C7 DELETE Menu ME POSTRESP 6 2 04 File Assign Change Create Define RN Display Print Run Select Set Help 2 gt x sje SESAM 15 DEC 2007 Program version 6 2 Long Term Response b Long Term Fatigue Response Co Spectrum Response Spectrum Response Variable Short Term Response SN curve Specific Point Speed reduction Data Wave Spectrum Wave Spreading Function Wave Statistics Workability Analysis Figure C 31 DELETE pulldown menu ME Delete L T R for Response Variable x L Delete L T F Response Variable Response Variable Apply Cancel Figure C 32 DELETE LONG TERM RESPONSE RESPONSE VARIABLE LONG TERM FATIGUE SESAM Postresp Program version 6 2 15 DEC 20074 C 29 ME Delete Response Co Spectrum x Delete Response Spectrum Response Co Spectrum Response Spectrum Cancel R E Delete Speed reduction Data 8 Speed reduction curve Apply Cancel Apply Cancel Figure C 33 DELETE RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE SHORT TERM RESPONSE SPECIFIC POINT SPEED REDUCTION DATA Postresp SESAM C 30 15 DEC 2007 Program version 6 2 ME Delete SN curve L3 L Delete Wave Statistics x ME Delete Wave Spreading R SN curve Name Wave Statistics Name Wave Spreading Functi
25. INS E SEA 13 000 11 730E107 18 301 30 015 NS F SEA 3 000 1 467E 07 18 301 29 800 INS F2 SE 3 000 1 2918 07 18 301 29 534 NS G SEA 3 000 1 074E 07 18 301 29 394 INS T SEA 3 000 1 939E 07 18 301 130 164 NS W SEA 3 000 9 233E106 8 301 29 197 where Name Name of the SN curve m Inverse slope of the first and second branch of the curve S Stress range at intersection with next branch units N m LogN Logarithm of number of cycles at branch intersection LogA Logarithm of number of cycles for stress range 1 0 The SN curve is converted from SI base units to the current set of consistent units based on the assumption that the Young s modulus of material corresponds to steel with E 2 1 x 10 N m The user defined SN curve requires the definition of slopes and intersection points A maximum of three slopes and two intersection points may be specified A consistent set of units must be used Postresp SESAM 2 12 15 DEC 2007 Program version 6 2 SN curve 1 0E 09 Stress 1 0E 08 T T T T T 1 DE 04 1 0E 05 1 0E 66 1 GE G7 1 DE 08 1 0E 03 1 0E 10 1 Number of cycles a DNV X Parameter values 1 50 3 4E 07 LagNO 8 301 LogAC 39 18 Figure 2 7 S N Curve DNV X 2 13 Stochastic Fatigue Calculations A stochastic fatigue analysis requires that a linearised frequency domain analysis is executed first This will genera
26. ME Create Response Co Spectrum ME Create Response Spectrum Figure C 18 CREATE RESPONSE CO SPECTRUM RESPONSE SPECTRUM SESAM Program version 6 2 Wl Create Response Variable Description Fatigue at midship f Response Type First Derivated Response Variable Name Apply Cancel Postresp 15 DEC 20074 C 17 x EE Create Response Variable Desi Response Type General Combination Combination Fat Include f Dvenwite Insert before Clear Help OK Apply Cancel Figure C 19 CREATE RESPONSE VARIABLE First Derivated General Combination Postresp SESAM C 18 15 DEC 2007 Program version 6 2 ME Create Response Variable Name FAT29 Description Fatigue at midship Response Type C nerf Water Depth Variable Contents Wave Direction Wave Frequency Real Imaginary Include Exclude Overwrite Insert before Clear Help Apply Cancel Forward speed or not Zero speed C Speed included Figure C 20 CREATE RESPONSE VARIABLE User Specified SESAM Postresp Program version 6 2 15 DEC 20074 C 19 ME Create Short Term Response Response Variable Wave Direction Wave Spreading Function Wave spectrum Prefix Minimum Sequence No Maximum Sequence No Apply Cancel ME Create SN curve SN curve name en Type of curve User Slope of first segment M0 Stress level at end first segment SO Log cycles at end first segment logNO Seco
27. Menus come in four different types Toggle buttons Radio boxes Option menus and Scrollable lists Selecting in a menu may cause changes in the layout of the dialogue box This will depend on the dialogue box in use A toggle button is a button that has two states On and Off Two examples are given in the Set Drawing box where the Frame button is Off and the Grid button is On Click on the button or on the corresponding label to switch the status of the button A radio box is a collection of toggle buttons where only one of the buttons can be active at any one time All buttons are visible on the screen simultaneously Click on a button or on the corresponding label to select that button An option menu is similar to a radio box in that it presents a number of alternatives of which only one is active at any one time It is however operated differently Click on the menu not the corresponding label to bring up the list of alternatives Then click on an alternative to select it Alternatively click on the menu and hold the button down then move the mouse pointer through the menu to the selected value and then release the mouse button The Spectrum Type menu in the Create Wave Spectrum box is an example of an option menu A scrollable list is a list of alternatives that is presented in a scrollable box Such a menu is used in order to preserve space or because the items in the list cannot be predicted before the menu is used Use the scroll
28. POSTRESP Database File Status OLD N 1322 Hovik Norway If opening an existing database file OLD Postresp will in addition give some information about the con tents of the database or if opening a new database file NEW give some guidelines on how to proceed This startup has opened a new database file called POSTRESP MOD and a new journal file called Pos tresp JNL this session is running on a VAX If the file specification is somehow incorrect Postresp will reissue the prompt for the database file prefix SESAM Postresp Program version 6 2 15 DEC 2007 4 9 Typing a double dot during the startup phase will abort the program The facilities that are available in line mode are described in Section 4 6 To exit the program type the EXIT command This will close all files and exit the program 4 2 6 Starting Postresp in a Batch Run Postresp must be run in line mode during a batch run It is recommended to prepare an input file first The batch command file can look like this prompt postresp status new interface line command filename forced exit This command will start Postresp and establish a new database status new run the program in line mode Anterface line use command input defined on file filename command filename and exit the pro gram after executing the input commands forced exit The referred input file must be a text ASCII file with file ex
29. PURPOSE The command is used for direct input of new transfer functions Maximum number of frequencies is 200 and they may be given in random order The forward speed may be given as a Froude number and will be taken into account in calculation of the statistical moments PARAMETERS name Name of the response variable txt Descriptive text of the response variable depth Water depth dir Wave direction 0 360 degrees freq Angular frequency real Real part of the transfer function value imag Imaginary part of the transfer function value froude Froude number EXAMPLES CREATE RESPONSE VARIABLE STRESS STRESS USER SPECIFIED 1000 ONLY 0 0 161 6 13E 05 2 90E 04 0 Oa LLS 5 64E 05 3 29E 04 0 01 9 4 32E 05 3 42E 04 SESAM Postresp Program version 6 2 15 DEC 2007 5 39 CREATE SHORT TERM RESPONSE sprea SHORT TERM RESPONSE resp dirt prfx mins maxs NONE PURPOSE To create short term response for a set of Tz values The wave spectra to be used have to be generated by the FULL RANGE alternative These spectra are named as a combination of the user given prefix and a sequence number i e prfx1 prfx2 prfx3 etc If the user wishes to know what sequence numbers available this might be done by use of the PRINT OVERVIEW WAVE SPECTRUM command The value calculated for each zero upcrossing period Tz is significant response pr Hs i e
30. SESAM 15 DEC 2007 Program version 6 2 CREATE WAVE SPECTRUM PIERSON MOSKOWITZ WAVE SPECTRUM name txt PIERSON MOSKOWITZ FULL RANGE tz min tz max incr SCATTER DIAGRAM SINGLE hs tz PURPOSE To create wave spectra based on a Pierson Moskowitz spectrum type PARAMETERS name txt FULL RANGE tzmin tzmax incr SCATTER DIAGRAM SINGLE hs tz EXAMPLES Name of the spectrum Descriptive text of the spectrum If FULL RANGE the 20 first letters will be used in addition to the internal text generation e g Tz 10 0 Full range calculation of PIERSON MOSKOWITZ spectra I e wave spectra with Hs equal to 1 0 and different Tz values given as a range will be generated This al ternative will create internal names which will be prfx where prfx is the first 4 letters of the name given and is an integer number in increasing order see Section 3 3 Minimum value of Tz for full range calculation Maximum value of Tz for full range calculation Increment between tzmin and tzmax Total number of generated spectra will be maximum minimum increment I A set of wave spectra are generated based on the Tz values with Hs values equal to 1 for the wave scatter diagram assigned to the corresponding wave spectrum shape A single wave spectrum is generated Significant wave height Hs Zero upcrossing wave period Tz CREATE WAVE SPECTRUM P
31. SESAM Program version 6 2 Second segment continues with m1 2 m0 1 Second segment continues with m1 m0 Second segment is horizontal Second segment is arbitrary Slope of second segment Third segment continues with m2 ml Third segment is horizontal Log cycles to failure at end second segment Slope of third segment SESAM Postresp Program version 6 2 15 DEC 2007 5 19 EXAMPLES CHANGE SN CURVE USE X USER NONE 3 0 3 4 7 0 ARBITRARY TAIL 5 HORISONTAL TAIL 8 301 CHANGE SN CURVE USE Y USER NONE 3 0 3 4e 006 7 0 ALIGNED WITH FIRST Postresp SESAM 5 20 15 DEC 2007 Program version 6 2 CHANGE SPECIFIC POINT SPECIFIC POINT name txt x coor y coor z coor PURPOSE To change the coordinates for a specific point PARAMETERS name Name of the point txt Descriptive text of the point X coor X coordinate in the global coordinate system y coor Y coordinate in the global coordinate system Z COOr Z coordinate in the global coordinate system NOTE When using results from Wadam or Waveship the global coordinate system has the origin in the mean free surface EXAMPLE CHANGE SPECIFIC POINT Pl MYPOINT 8 301 5 2 17 35 SESAM Postresp Program version 6 2 15 DEC 2007 5 21 CHANGE WAVE SPECTRUM WAVE SPECTRUM name tx o several parameters PURPOSE To change an existing wave
32. SS HDD t2cAujuj Aj ua B 124 Using the moment property E u 3 2n 1 for standard normal variables we find that u l uu 0 and uj 2 Substituting these values into Equation B 124 gives KIOO Q 0 Q c 2207 B 125 das A pr Higher central moments Qo are found similarly Explicit results for Qo and Qo are 3 NE 3 3 Do 2 2 33 OO Ot Xy cpu 36 Au us 3c uu hj Un B 126 4 24 4 4 3 3 272 2 3 3 44 OO O t x cju Acj Aqu uy 6c Muun Aci uu hug B 127 Again using the Gaussian moment property the only non zero quantities in these expressions are found to be uy 2 uy 8 uj 3 uU 10 and uj 60 Substituting into Equation B 126 and Equation B 127 we find the cumulant values 3 KOA 6c A 85 B 128 217 13 K4 Q 484 c TA B 129 The total cumulants of x t follow by summing Equation B 122 Equation B 125 Equation B 128 and Equation B 129 in accordance with Equation B 121 The moments of x t are then found to be y 2N x M2 B 130 2 cal 2 2 9 7 Y e t2X B 131 k 1 aN 2 3 3 Q4 dy GA SA G B 132 k 1 2N Q4 Y 484 D o 3 B 133 Postresp SESAM B 28 15 DEC 2007 Program version 6 2 In these equations the s represent pure second order effects the c s represent pure first order effects and terms with products of s and c s represent interaction of first and second order
33. bar to manoeuvre through the list and select a value by clicking on it Only one value can be selected at any one time The Scatter Diagram list in the Create Wave Spectrum box is an example of a scrollable list A push button is a button that causes an action to happen when it is clicked on OK Apply and Cancel but tons are represented in the two boxes shown above All dialogue boxes have a standard set of buttons at the bottom of the box These buttons are described in the Section 4 5 4 If the label of a pushbutton is followed by three dots the button will open a new dialogue box SESAM Postresp Program version 6 2 15 DEC 2007 4 17 In addition to these items there are a few more complex input items that are described in Section 4 5 5 and Section 4 5 6 All relevant dialogue boxes are shown in Appendix C 4 5 4 The standard Buttons in a Dialogue Box A dialogue box will contain one or more of these standard buttons placed at the bottom of the box OK Accept the contents of the box and close the box The box will not be closed if there is an error in the information inside the box Apply Accept the contents of the box The box is not closed Cancel Close the box without accepting the contents or after having clicked Apply All dialogue boxes have a default push button that is activated by typing Return when the dialogue box is active This push button is the OK or the Apply button The default button will be highlighted or framed
34. des MR Nu DISPLAY RESPONSE SPECTRUM 10 11 12 SET TITLE Short term resp for HEAVE long crested sea v ES n DISPLAY SHORT TERM RESPONSE BI xg X Postresp SESAM A 6 15 DEC 2007 Program version 6 2 SET TITLE Short term resp for HEAVE short crested sea 1 p DISPLAY SHORT TERM RESPONSI 789 rj CJ SET TITLE Short term resp for PITCH long crested sea 74 E va DISPLAY SHORT TERM RESPONSE 456 SET TITLE Short term resp for PITCH short crested sea EA font D DISPLAY SHORT TERM RESPONSE 10 11 12 SET TITLE Long term response for HEAVE Wow Wo DISPLAY LONG TERM RESPONSE RESPONSE VARIABLE HEAVE LOG 0 45 90 DISPLAY LONG TERM RESPONSE RESPONSE VARIABLE HEAVE WAVE DIR 6 SET TITLE Long term response for PITCH MORA T DISPLAY LONG TERM RESPONSE RESPONSE VARIABL DISPLAY LONG TERM RESPONSE RESPONSE VARIABL PITCH LOG 0 45 90 PITCH WAVE DIR 6 El El Exit from Postresp o oP oe FILE EXIT SESAM Postresp Program version 6 2 15 DEC 2007 A 7 SESAM POSTRESP 8 1 01 26 NOV 1993 Wave spectrum used in response spectra Wave Spectrum 0 N 2 E RE a cC o ho 2 o s o C ul 1 0 1 2 Angular Frequency rad s AX FRPM11
35. g Where g is the acceleration due to gravity H Tp M N and y are dependent of a set of semi empiric parameters The functional relations are different for the swell part and the wind part and are different according to whether the total sea state is regarded as wind dominated or swell dominated Postresp SESAM B 8 15 DEC 2007 Program version 6 2 B 1 7 1 Basic Constants The following set of constants is basic to all the others AF 6 6 AE 2 0 AU 25 0 A10 0 7 Al 0 5 RG 35 0 KG0 3 5 KG1 1 0 R 0 857 K0 0 5 K00 3 2 M0 4 0 B1 2 0 A20 0 6 A2 0 3 A3 6 0 S0 0 08 S1 3 0 B2 0 7 B3 3 0 B 1 7 2 Definition of sea state type The seastate is defined as wind dominated or swell dominated according to whether the primary peak period is below or above a value TF given by 1 TF AF Hs BI Based on this lower and upper period fractions are defined TF TP _ TF TP B 33 Eq Ey TF AENHs TF AU SESAM Program version 6 2 15 DEC 2007 B 1 7 3 Wind dominated sea Primary peak Significant wave height EL 2 Hs Hs L A10 e A10 Spectral period Ipp Tp Peak enhancement factor y KG 1 KGO e High frequency exponent N KOVHs K00 Spectral width exponent M M0 P Secondary peak Significant wave height Spectral period Hs 27 Hs g Ip y Hs dicam A10 2 Postresp
36. real standard normal processes x t x 0 x t B 119 2N where x t cut AG DI j l The statistics of x t can now be computed in terms of the c s and Ms and the moments of the u f proc esses From Equation B 119 2N x t Q0 B 120 j l where O t cu DO Xu 1 Note that at fixed time f the quadratic random variables Q t are independent Computations are therefore simplified by considering not the ordinary moments of x f but rather its I cumulants x because cumulants of independent components can be directly summed amp x 3 90 B 121 We focus here on the first four cumulants x m K x 76 K3 x a30 and Ka4 x 7 04 3 6 Note that K gt x p and k3 x us in terms of the central moments u E x m while 4 x 14 305 Because E u 0 and Flu 1 the first cumulant mean value is K Q0 Q 4 B 122 For notational simplicity we shall use the overbar as an alternative symbol for ensemble expectation For general central moments of the form Q t o it is useful to subtract Equation B 122 from Equa tion B 120 before averaging Q t O D Q cut Jc usi B 123 SESAM Postresp Program version 6 2 15 DEC 2007 B 27 Here uu 1 is the second Hermite polynomial which has zero mean and is uncorrelated with u The var iance of Q 1 follows by squaring Equation B 123 and taking averages ler m u 22 K O t Q 0 0 Gu
37. 0 Postresp SESAM 5 12 15 DEC 2007 Program version 6 2 ASSIGN WAVE STATISTICS WAVE STATISTICS dir name PURPOSE To assign a wave statistics model to a wave direction The assignment will override the previous assign ment PARAMETERS dir Wave direction name Name of the wave statistics model EXAMPLES ASSIGN WAVE STATISTICS 180 DNV NA ASSIGN WAVE STATISTICS 210 DNV NA ASSIGN WAVE STATISTICS 240 DNV NA ASSIGN WAVE STATISTICS 270 DNV NA ASSIGN WAVE STATISTICS 300 DNV NA ASSIGN WAVE STATISTICS 330 DNV NA SESAM Postresp Program version 6 2 15 DEC 2007 5 13 CHANGE LONG TERM FATIGUE LONG TERM RESPONSE MATRIX RESPONSE VARIABLE SPECIFIC POINT WAVE SPECTRUM WAVE SPREADING FUNCTION WAVE STATISTICS CHANGE PURPOSE This is used to change previously created responses and wave statistic tools The options and subcommands are mainly the same as for the corresponding CREATE command The pro gram will ask for the name of the object and the default values of the different subcommands will be as given before Postresp SESAM 5 14 15 DEC 2007 Program version 6 2 CHANGE LONG TERM FATIGUE LONG TERM FATIGUE resp dir sn curve PURPOSE To change long term fatigue for a selected set of response variables and a set of global wave directions PARAMETERS resp Name of the response variables for
38. 1 4 1 5 2 1 2 2 2 3 2 4 2 5 2 6 21 2 8 2 9 2 10 2 11 2 12 2 13 3 1 3 2 Table of Contents INTRODUCTION Prec rp M 1 1 Postresp Postprocessor for Statistical Response Calculations sesseeeeeeee 1 1 Postresp 1n the Sesam System ice aei eee rrt ete etre epe pe ena Ire eine e ep ct ce egeta 1 2 How to read this Manual ertet ee eee tege ete e eig te eee te ne eet egets 1 3 Status List Aasta 1 3 Postresp extensiornis 5 iots stats ede p buie iati OG metet 1 4 FEATURES OF POS ERESP iyscsccusestsassspexsesossacssoonsteonsesoavessontostessespunoesesssccsesspucccsedeatereks 2 1 Response Variables iine era eaten i Papua recede tuc ee c heile tenis 2 1 Wave Spetta dose eter am cadesodecont ante a AAA 2 2 Wave Energy Spreading FUnctions ccccccecccessesssesseceseceeceeseeesecsaecssenecseeeeseecsecaeceeseneseseesaeenseenes 2 3 WAVE Statistics enitn petet dst equtuimetuiiemetu merid 2 4 Response Spectra tert e cde wands nee ete eee atenerne fetter 2 6 Short Term Response epe repite ett er et RR McRae deceit does dca ette edd 2 7 Short Terra StatistlCs uran at Fer e OO ege EIS ere eta OQ IER I RO EET TUTO ia 2 8 Long Term Response ied ae RR TR Ur EUER eT mantenia Re genae 2 8 Equation of Motion 5 n ei E EH e He tetigere ti edet cate ce e e dvd des 2 9 W orkability2Anal ysis 5 ecce e er eoe eate e e E ete e deve le ia ege 2 10 Second Order Statist Cs 2 soc er o e eee DD Ue er su
39. B3 1 Basic Transfer FUnctions ccsccesscssssesseeseconececcsesceesesssesasesseceneseneecseceaeceaeeescsatesaneensens B 15 B3 2 Standard Combinations esses enne entren nennen enne B 15 B33 Special Combinations ssen eet metere ie b e festere B 16 B4 SHORT TERM RESPONSE spa B 16 B AT Spectral Moments o bert pe repetere etae ade obe a sets eis B 16 B42 Response Variances etate tese tectae cte SA HUN e a bedere 2E eS Sad T ER B 17 B4 3 Response Covariance cccceseeseessesseescesecsecsceeseeceseesecaaeeaeeaeseeceeceaecaeeaeeeeeeaeeaecaecaeeaeentes B 18 B44 Response Maxima secin nthe htni hier nn Anis oen eE E Eai B 18 BS gt CONG TERM RESPONSE sessmscom ts sl mo al B 19 B5 1 Derivation of Long Term Distribution essere enne nennen B 19 B6 Theoretical Background for Second Order Statistics sse B 21 B 6 1 Introduction wo cc cccceccssccccsssesssceccccecscseescsccusesseeseccsesesessssceesessnsssesesseessaseseccssessasees B 21 B7 B 6 2 Problem Transformation ccccccc cc cccccecccccecscsssssccceccesssseeesecesessssececescessstssssesseesessseseesees B 21 B 6 3 Response Statistics cccceccccssecsseeseceseeesceeseceseceseeeeeeeseesaeceaeceecseeeessecsaenseeeeseseeeseeeseeeaeees B 26 Frequency Domain Fatigue sere ger eie ste a e euet ine t deer eere ated B 28 B 7 1 Basic Assumption n reco teer det deii e e patte iie que B 28 BA 2 lBaSICIeSUltS eere
40. C 3 C2 FILE Menu Figure C 2 FILE pulldown menu ME Read Hydrodynamic Response File iJ Figure C 3 FILE READ Postresp SESAM C 4 15 DEC 2007 Program version 6 2 Print Setup Figure C 4 FILE SELECT PRINTER C3 ASSIGN Menu Ei POSTRESP 6 2 04 Figure C 5 ASSIGN pulldown menu SESAM Postresp Program version 6 2 15 DEC 20074 C 5 ll Assign Wave Spectrum Shape ME Assign Probability Wave Statistics Spectrum Type Wave Direction DNV NA Pierson Moskowitz DNV WW C Jonswap C General Gamma C ISSC Sea States Probability pes DK Cancel ME Assign Statistics Cancel Wave Direction Wave Statistics DNV NA Il Assign Spreading Function Wave Statistics Wave Spreading Sea States COS2 v All DNV WW cos4 NONE C Part OK Apply Cancel Wave Direction Speed Curve Name SRC1 Cancel Figure C 6 ASSIGN WAVE SPECTRUM SHAPE WAVE SPREADING FUNCTION WAVE DIRECTION PROBABILITY WAVE STATISTICS SPEED REDUCTION CURVE WAV E DIRECTION Postresp SESAM C 6 15 DEC 2007 Program version 6 2 C4 CHANGE Menu L POSTRESP 6 2 04 File Assign Keii Create Define Delete Display Print Run Select Set Help 21 El Long Term Fatigue Long Term Response Matrix Response Variable SN curve Specific Point Wave Spectrum Wave Spreading Function Wave Statistics Figure C 7 CHANGE pulldown menu ME Change Long Term Fatigue x Change Long Te
41. COS2 ALL ASSIGN WAVE SPECTRUM NOR1 PIERSON MOSKOWITZ ALL Create a long term response for the response variables HEAVE and PITCH for the main wave directions 0 45 90 degrees CI o oP oe CREATE LONG TERM RESPONSE RESPONSE VARIABLI J HEAVE PITCH Change print unit from default screen to a file named APP A o oP oe En d PRINT DESTINATION FILE PRINT PAGE ORIENTATION LANDSCAPI PRINT FILE A Es d Gl EEE 3 El HJ Du ou oo Postresp SESAM A 4 15 DEC 2007 Program version 6 2 Set common text in the heading of each plot do oe SET TITLE Turtorial example for Postresp Users Manual Ten ter ey 2 Print sequence total overview all wave spectra defined wave spreading function named COS2 spacing 45 degrees wave statistics named NORL response variable HEAVE with all headings response spectra created a short term responses created short term statistics for all response spectra created with a Rayleigh distribution and for 3 given sea state durations long term response for HEAVE motion with 5 return periods de o AP AP o AP o AP AP o AP I PRINT OVERVIEW ALL PRINT WAVE SPECTRUM PRINT WAVE SPREADING FUNCTION COS2 45 PRINT WAVE STATISTICS NORLI PRINT RESPONS VARIABLI HEAVE PRINT RESPONSE SPECTRUM
42. Create Wave Spectrum El ME Create Wave Spectrum Name Name Description Description 0 Spectrum Type Spectrum Type Torsethaugen v Single or Full Range Single or Full Range FulRange gt Minimum Tp Maximum Tp L Parameter Increment N Parameter Apply Cancel Apply Cancel Figure C 24 CREATE WAVE SPECTRUM General Gamma Torsethaugen SESAM Program version 6 2 15 DEC 20074 Postresp C 23 lll Create Wave Statistics Es ll Create Wave Statistics Type Scatter Diagram Input Specifiation Probability Diagram Hs Tz Probability Include Exclude Overwrite Insert before Clear Help Apply Cancel Type ISSC Scatter Diagram vi Input Specifiation Occurence m Diagram Hs T1 mean Occurence Include Exclude Overwrite Insert before Clear Help Apply Cancel Figure C 25 CREATE WAVE STATISTICS Scatter Diagram Postresp SESAM C 24 15 DEC 2007 Program version 6 2 ME Create Wave Statistics Name Weather Data Description Type Nordenstrom v TZ Distribution Normal Number of SD AT parameter Wave Period Ty Probability Tv BT parameter HC HO Tz Coefficient Gamma Number of Hs Include Exclude Overwrite Maximum Hs Insert before Clear Help AH parameter BH parameter Steepness Figure C 26 CREATE WAVE STATISTICS Nordenstrom SESAM Postresp Program version 6 2 15 DEC
43. LONG TERM RESPONSE RESPONSE VARIABLE respt SLAMMING point LONG TERM RESPONSE PURPOSE To print long term response for a selected response variable or long term slamming in a specific point PARAMETERS RESPONSE VARIABLE Long term response for a selected response variable is printed SLAMMING Long term slamming is printed resp Response variable s for which the long term response s is printed point Specific point where long term slamming has been calculated Postresp SESAM 5 112 15 DEC 2007 Program version 6 2 PRINT MATRIX FULL MATRIX freq ADDED MASS body SINGLE ELEMENT elem BODY MASS FULL MATRIX freq POTENTIAL DAMPING body MATRIX SINGLE ELEMENT elem RESTORING FULL MATRIX freq TOTAL DAMPING body SINGLE ELEMENT elem VISCOUS DAMPING PURPOSE To print global matrices either added mass and damping matrix as a function of the frequencies or the total matrix for a selected frequency or print of the inertia coefficient body mass and restoring matrix PARAMETERS ADDED MASS POTENTIAL DAMPING TOTAL DAMPING VISCOUS DAMPING RESTORING BODY MASS FULL MATRIX SINGLE ELEMENT body freq elem Added mass matrix Potential damping matrix Total damping matrix Viscous part of the damping matrix Hydrostatic restoring matrix Inertia coefficient body mass matrix A 6x6 matrix for a given frequency wi
44. Line Mode gt Expressions Built In Variables Figure C 63 HELP PROGRAMMING MODE pulldown menu SESAM Postresp Program version 6 2 15 DEC 2007 REFERENCES 1 REFERENCES 1 Nordenstrom N 1971 Methods for Predicting Long Term Distributions of Wave Loads and Probability of Failure for Ships Part 1 Environmental Conditions and Short Term Response Det norske Veritas report no 71 2 S 2 Jorgensen D Korbijn F McHenry G Mathisen J 1985 Wave Load Manual Progress Report No 2 Vertical Plane Loads Det norske Veritas report no 85 2036 3 Mathisen J 1986 Slamming Calculations in NV1473 Det norske Veritas report no 86 2003 4 Ochi M K 1964 Extreme Behaviour of a Ship in Rough Seas Slamming and Shipping of Green Water Trans SNAME Vol 72 5 Ochi M K 1964 Prediction of Occurrence and Severity of Ship Slamming at Sea 5th ONR symposium on Naval Hydrodynamics Bergen 6 Kim and Yue 1988 The nonlinear sum frequency wave excitation and response of a tension leg platform Proc of the 5th BOSS conference Trondheim 7 Marthinsen T and Winterstein S R 1992 Second order load and response statistics for tension leg platforms Rpt RMS 9 Reliability of Marine Structures Program Stanford University 8 Molin B and Chen X B 1990 Vertical resonant motions of tension leg platforms Second order sum frequency loads on one TLP col umn FNS Proj No 24841 Division Exploitation En Mer Institut
45. POINT SHORT TERM RESPONSE SESAM Postresp Program version 6 2 15 DEC 20074 C 35 ME Display Wave Spectrum E t8 EE E E Spectrum Name E Display Sectional Force Diagram Degree of freedom Lower sequence No Upper sequence No Wave Direction Frequency W1 W2 W3 OK Apply Cancel incide _Exclude Overwrite ME Display Wave Spreading Function El Insert before Clear Help E em Function Name cosz2 cos4 OK Apply Cancel ME Display Wave Statistics Apply Cancel ME Display Speed reduction Curve x Speed reduction Curve Apply Cancel Figure C 41 DISPLAY SECTIONAL FORCE DIAGRAM SPEED REDUCTION CURVE WAVE SPECTRUM WAVE SPREADING FUNCTION WAVE STATISTICS Postresp SESAM C 36 15 DEC 2007 Program version 6 2 C9 PRINT Menu ME POSTRESP 6 2 Data Set 2 leli tee sept Long Term Response Long Term Fatigue Matrix Overview Response Variable Second Order Statistics Short Term Response Short Term Statistics Short Term Fatigue Specific Point Wave Spectrum Wave Spreading Function Wave Statistics Workability Analysis Figure C 42 PRINT pull down menu SESAM Postresp Program version 6 2 15 DEC 20074 C 37 Response Variable Second Order Statistics Short Term Response Short Term Statistics Short Term Fatigue Specific Point Wave Spectrum
46. REDUCT ION PRINT WAVE SPECTRU PRINT WAVE SPREADING FUNCTION PRINT WAVE STATISTICS PRINT WORKABILITY ANALYSIS mH E U AJ H Z 5 3 NANNNANNAND DD a O AJ 5 3 I E E Program version 6 2 SESAM Program version 6 2 15 DEC 2007 EQUATION SOLV ELECT DATA SET Lt C ra El uU 3 d E l COMPANY NAM l DISPLAY l DRAWING GRAPH PLOT PRINT TITLE 3 3 3 3 3 Gl DANNANANANAUNAN uc E Ed Dd Ed Ed Dd bd Dd E d Postresp 5 5 Postresp SESAM 5 6 15 DEC 2007 Program version 6 2 ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION WAVE DIRECTION PROBABILITY ASSIGN WAVE SPECTRUM SHAPE WAVE SPREADING FUNCTION WAVE STATISTICS PURPOSE The assign command is used to assign wave spectra and wave energy spreading functions to wave statistics models or to assign speed reduction data probabilities and wave statistics models to existing wave direc tions SESAM Postresp Program version 6 2 15 DEC 2007 5 7 ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION SPEED REDUCTION CURVE WAVE DIRECTION dir name PURPOSE To assign a speed reduction curve to an existing wave direction for later use in calculating long term statis tics and long term fatigue calculations The assignment will override the previous assignment PARAMETERS dir Wave direction name Name of speed reducti
47. Solver Figure C 54 RUN EQUATION SOLVER Original Frequencies C11 SELECT Menu ME POSTRESP 6 2 04 Figure C 55 SELECT pulldown menu Postresp SESAM C 48 15 DEC 2007 Program version 6 2 ME Select Data Set Figure C 56 SELECT DATA SET C12 SET Menu ME POSTRESP 6 2 04 2 He tee Figure C 57 SET pulldown menu SESAM Program version 6 2 ME Company Name Company Name Apply Cancel ME Drawing Options IV Grid Frame Character Type Software m Font Type Font Size Relative v Apply Cancel Size factor Graph Line Options IV Marker Marker Size Line Type Line Number El Type Default Marker Type Line Number El Type Defaut soy Cancel 15 DEC 20074 Postresp C 49 El ME Display Options Device WINDOWS Destination Screen Y Workstation Window Left Border Right Border Bottom Border Top Border OK Cancel ME Pie Chart Options Exploded Segment C Segment Name Off Filling Solid m Label Visibility Show v Horizontal m Automatic v Value On v OK Apply Cancel Orientation Position Figure C 58 SET COMPANY NAME DISPLAY DRAWING GRAPH LINE OPTIONS GRAPH PIE CHART Postresp SESAM C 50 15 DEC 2007 Program version 6 2 ME Graph XAxis Attributes x ME Graph YAxis Attributes Limits Free C Fixed Spacing Linear Y Decimal Format General v T
48. Variable o U 3 E a E lt 1000 Wove length m ALHEAVE Dir 0 0 t HEAVE Oir 45 0 D HEAVE Dirz90 0 SESAM Program version 6 2 Postresp A 14 15 DEC 2007 SESAM POSTRESP 6 1 01 26 NOV 1995 Transfer function for first order motion Amplitude of Response Variable o ue 2 E mr Q El lt Wave length m A PITCH Dir 0 0 PITCH Dir 45 0 DE PITCH Dir 90 0 SESAM Postresp Program version 6 2 15 DEC 2007 A 15 SESAM POSTRESP 6 1 01 26 NOV 1993 Transfer function for first order motion Amplitude of Response Variable o Es 2 ET nO m a lt 20 25 Wave period seconds A HEAVE Dir 0 0 F HEAVE Dir 45 0 O HEAVE Dir 90 0 SESAM 15 DEC 2007 Program version 6 2 Postresp A 16 SESAM POSTRESP 6 1 01 26 NOV 1993 Transfer Function for first order motton Amplitude of Response Variable o 0 2 v a E x Wove period seconds PITCH Dir G 0 F PITCH Dir 45 0 El PITCH Dir 90 0 SESAM Postresp Program version 6 2 15 DEC 2007 A 17 SESAM POSTRESP 8 1 01 26 NOV 1993 Response spectra for HEAVE long crested sea Response Spectrum 0 N gt a E n a c o D 2 o t o c ul 1 0 Angular Frequency rad s 2 1 HEAVE Dir 0 0 FRPM11 Identical parameters 2 HEAVE Dir 45 0 FRPM1 Depth 250 0 0 3 HEAVE Dir 90 0 FRPMII Postresp SESAM A 18 15 DEC 2007 Program version 6 2 SESAM
49. WAVE SPECTRUM Postresp SESAM C 12 15 DEC 2007 ME Change Wave Statistics Description Type Scatter Diagram x Hs z Probability Include Exclude Overwrite Insert before Clear Help OK Apply Cancel Program version 6 2 x ME Change Wave Statistics Description Type fan Param Scatter v Spectrum Ochi Hubble S Diagram 5 75 10 25 10 0 1 75 12 25 9 75 152 25 141 0 Hs swell Tp swell Shape swell Hs wind Tp wind Shape wind Probability Include Exclude Overwrite Insert before Clear Help Apply Cancel Figure C 14 CHANGE WAVE STATISTICS Scatter Diagram All Param Scatter SESAM Postresp Program version 6 2 15 DEC 20074 C 13 Create Wave Statistics Name Weather Data Description Nordenstreom Type Nordenstrom v Number of Tz TZ Distribution Number of SD AT parameter BT parameter HC HO Tz Coefficient G amma Number of Hs Include Exclude Overwrite Maximum Hs Insert before Clear Help AH parameter BH parameter Steepness Figure C 15 CHANGE WAVE STATISTICS Nordenstrom Postresp SESAM C 14 15 DEC 2007 Program version 6 2 C5 CREATE Menu E POSTRESP 6 2 04 Figure C 16 CREATE pulldown menu SESAM Postresp Program version 6 2 15 DEC 20074 C 15 NE Create Long Term Fatigue Figure C 17 CREATE LONG TERM FATIGUE LONG TERM RESPONSE Postresp SESAM C 16 15 DEC 2007 Program version 6 2
50. a RYE n temo eee he B 28 B 7 3 Short Term Fatigue Linear Model sese B 29 B7 4 Long Term Fatigue Sum over Seastates cccceccesssesssesseceseeeeeeesecaecsseseeeeeeeeseeeseeeaeens B 29 B7 5 Long Term Fatigue from Long Term Distribution eese B 29 APPENDIX C PULLDOWN MENUS AND DIALOGUE WINDOWS OF POSTRESPC 1 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C 13 POSTRESP dialogue window and commands sse eee C 2 FILE Menu C C 3 ASSIGN Menu edo en ea cai ets eccl etecte ec bete dee ner nasa C 4 CHANGE MEDI ota C 6 CREATE MENM ie in ett E Rer etel testet ir e on feto leidet C 14 DEFINE Menu nn nee iaa IE Pa ELS C 26 DELETE MENU sit pac ee Betis ES C 28 DISPLAY Menu etie tem Lm ii Gi o ue pae te e tdi te e C 31 PRINJI MenU s get ccs ve detect siden dem oet te Eten o e ee e i nee ete Toe C 36 RUN MOnU circiter d e Fe a Ee e sie een C 46 SBELEGT MO6nBU dio Ec dra inn NV re ER bo RET OLo Ba E fori eom d eco oe ota emat C 47 SET Mn Us H C 48 HELP Merni neni ume ido E EE C 51 SESAM Postresp Program version 6 2 15 DEC 2007 1 1 1 INTRODUCTION 1 1 Postresp Postprocessor for Statistical Response Calculations Postresp is a general interactive graphic postprocessor for postprocessing of general responses given as transfer functions in the frequency domain or postprocessin
51. as a single sum 2N x t 7 X Awe B 111 j 1 SESAM Postresp Program version 6 2 15 DEC 2007 B 25 In Equation B 111 the second order response x gt t has been written as a sum of standard normal processes u t squared Returning now to the first order response x t the summation in Equation B 96 can also be written in matrix form as x 0 5 H7 ut El B 112 where a is as before and H is the vector of first order transfer function values H o H B 113 H op Again the vector of Gaussian processes is standardized by factoring the variances o into the transfer func tion values m EE YF B 114 HE sa he with the following definition of y Ya Toy 0 k LN B 115 Equation B 109 however provides the definition z Qu B 116 which can be substituted into Equation B 114 to give 2N x 6 you S cu B 117 j 1 Equation B 117 imply the definition of the c s 2N C j 2j H 0 0 0 Hi oo dv el B 118 k 1 Postresp SESAM B 26 15 DEC 2007 Program version 6 2 The c s are real by virtue of the conjugate symmetry in the scaled eigenvectors In Equation B 117 the first order response x f has been written as a sum of the same standard normal processes u 1 that appear in the second order response expression B6 3 Response statistics Thus the total combined response to the N frequency components of input has been restated in terms of 2N
52. do not relate to any given Froude number PARAMETERS ON OFF Switch speed reduction on or off off is default SESAM Postresp Program version 6 2 15 DEC 2007 5 71 DEFINE STRUCTURE ORIENTATION STRUCTURE ORIENTATION angle PURPOSE To define the global orientation of the structure The orientation will be used when reading in external scat ter diagrams from a file PARAMETERS angle Angle relative to global X axis in degrees The angle is given positive anti clockwise Postresp SESAM 5 72 15 DEC 2007 Program version 6 2 DELETE LONG TERM FATIGUE LONG TERM RESPONSE RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE SHORT TERM RESPONSE DELETE SN CURVE SPECIFIC POINT SPEED REDUCTION DATA WAVE SPECTRUM WAVE SPREADING FUNCTION WAVE STATISTICS WORKABILITY ANALYSIS PURPOSE This is used to delete response types previously created The subcommands are mainly the same as for the corresponding CREATE commands The program will ask for the name of a the response and delete all data stored under this name SESAM Postresp Program version 6 2 15 DEC 2007 5 73 DELETE LONG TERM FATIGUE LONG TERM FATIGUE respt PURPOSE To delete long term fatigue for a given response variable PARAMETERS resp Name of the response variable for which the long term fatigue shall be deleted Postresp SESAM 5 74 15 D
53. energy of such a system may be described by a directional wave spectrum S c o of the form S a S o f a B 1 where S is the unidirectional wave spectrum with energy distributed according to wave frequency The function f a represents the directional distribution of energy in the waves and is defined in the follow ing way Loe ens B 2 where a represents the angle of the elementary waves relative to the main direction B of the short crested wave system and 6 is the wave direction spacing See Figure B 1 The larger the value of n the more sharp is the distribution function and the more concentrated is the direc tional energy distribution SESAM 15 DEC 2007 Program version 6 2 Postresp B 2 Furthermore the denominator of Equation B 2 is to satisfy the requirement n 2 f flajda 1 B 3 n 2 The cosine n directional distribution is then a 8 2 f cos xdx 8 2 fto A t 2 lt a lt n 2 eT B 4 f cos xdx B 4 n 2 0 otherwise X m E Main direcLion c EM of irregular Sd E wave system Directions of elementary sinusoidal waves xa mis Figure B 1 Definition of heading angles between ship and waves SESAM Postresp Program version 6 2 15 DEC 2007 B 3 B 1 2 Pierson Moskowitz Spectrum The Pierson Moskowitz spectrum may be written as 2 2 pi 4 S o ag ae 2 B 5 where a is a slope parameter set equal to 0 0081 Phillip s Constant g is the acceleration due to gr
54. file Instead the selected value is logged as it is presented in the list 4 6 8 Selecting several Alternatives from a List In some cases a list of items is presented from which one or more items can be selected An example is the PRINT RESPONSE VARIABLE command where a number of response variables may be selected for print In this selection both wildcards and abbreviation may be used but not inside the same text The syntax for the selection allows for more flexibility then in the single selection case because it may be of interest to keep modifying the selection for some time before accepting it The selection process consists of one or more selection operations each of which follow the syntax described below If more than one opera tion is required to complete the selection the selection must be enclosed in parenthesis The syntax for a single selection operation is INCLUDE text Include the item s matching text in the selection Set the default status to IN CLUDE Any items specified after this will be included in the selection until the status is changed ONLY text Set the current selection to only the item s matching text Any previous selection is deselected first Set the default status to INCLUDE Any items specified after this vvill be included in the selection until the status is changed EXCLUDE text Exclude the item s matching text from the selection Set the default status to EX CLUDE Any items specified
55. is identical to the PLOT command except that it accesses the screen device SESAM Postresp Program version 6 2 15 DEC 2007 5 91 DISPLAY RESPONSE CO SPECTRUM RESPONSE CO SPECTRUM body number PURPOSE To display one or several response spectra of type cross spectrum created by the program Note that response spectra calculated by using general gamma spectrum are not available for display PARAMETERS body Optional body identification Only available if DEFINE PRESENTATION OPTION SI MULTANEOUS BODIES is set to ALL number Reference number of the response cross spectrum Postresp SESAM 5 92 15 DEC 2007 Program version 6 2 DISPLAY RESPONSE SPECTRUM RESPONSE SPECTRUM body numbert PURPOSE To display one or several response spectra of type auto spectrum created by the program Note that response spectra calculated by using general gamma spectrum are not available for display 7 response spec tra can be displayed together PARAMETERS body Optional body identification Only available if DEFINE PRESENTATION OPTION SI MULTANEOUS BODIES is set to ALL number Reference number of the response spectrum SESAM Program version 6 2 15 DEC 2007 DISPLAY RESPONSE VARIABLE Postresp 5 93 naml dir Froude RESPONSE VARIABLE body SECOND ORDER SURFACE nam2 dirl dir2 CONTOUR nam2 dirl dir2 G
56. load spectrum PARAMETERS name Name of the spectrum txt Descriptive text for the spectrum several parameters Wave spectrum parameters These are dependent of the spectrum type previously given See below GENERAL GAMMA hs Significant wave height Hs tz Zero upcrossing wave period Tz Isp l parameter in the general gamma spectrum nsp n parameter in the general gamma spectrum JONSWAP hs Significant wave height Hs tz Zero upcrossing period Tz alpha Slope parameter o p freq Peak angular frequency op gamma Enhancement factor y sigmaa Left width sigmab Right width oj OCHI HUBBLE HsS Significant wave height for the swell part TpS Peak period for swell part Gams Shape parameter for swell part Postresp 5 22 HsW TpW GamW SESAM 15 DEC 2007 Program version 6 2 Significant wave height for the wind part Peak period for wind part Shape parameter for wind part PIERSON MOSKOWITZ hs tz ISSC hs tl Significant vvave height Hs Zero upcrossing wave period Tz Significant wave height Hs Mean wave period T1 USER SPECIFIED freq dens EXAMPLES CHANGI E WAV E SP Input angular frequency Specified energy density for input frequency ECTRUM OCHIHUB Ochi Hubble spectrum 2 0 20 0 1 5 6 0 10 0 3 0 0 SESAM Postresp Program version 6 2 15 DEC 2007 5 23 CHANGE WAVE SPREADING FUNCTION COSINE POWER USER SPECIFIED
57. more and if the spacing is constant If the program does not find a direction it will use the direction for or 180 degrees Note that this is only correct if the vessel does not have any forward speed and is doubly symmetric Example Wave directions available 0 45 90 135 180 degrees Main wave direction 45 degrees and short crested sea Which results in The relative directions 90 45 0 45 90 degrees and available directions 135 0 45 90 135 degrees The wave energy spreading function may be a cos 0 where n is an integer value i e cos 0 cos 0 etc The function value is not directly the cos 0 value but the integral of the function from 0 A0 2 to 6 A6 2 Postresp SESAM 2 4 15 DEC 2007 Program version 6 2 Wave spreading used for short crested seo Wove Spreading Function CCS2 Cos 2 Veight ZZ WG ie so 00 150 Relative vove airection Deg Figure 2 3 Wave spreading function based on cos2 8 A user specified spreading function is typed in with the relative directions and the corresponding weights When a wave spreading function based on a cosine function is printed displayed or plotted the program will ask for which relative spacing to use in the presentation 2 4 Wave Statistics The wave statistics model describes the sea state conditions during a long term period and consists of mainly zero upcrossing periods T and significant wave heights H and
58. na e RR RE UT IRI EUN GERNE dee UE sae aset edle edet aie 4 1 Starting Posiresp c ni ens eorr mm ep E ie ii o e REED gal 4 2 4 2 1 Starting Postresp from Manager with Result Menu seorernnrnnrnrrnnrerrvrrernnrnnennrnrerrnrrnrneenn 4 3 4 2 2 Starting Postresp from Manager with Utility Run Menu seen 4 5 4 2 3 Starting Postresp from Manager Command Line or Journal File 4 5 4 2 4 Starting Postresp in Graphics Mode sse ene 4 6 4 2 5 Starting Postresp in Line Mode on Unix essere enne 4 8 4 2 6 Starting Postresp in a Batch Run ener erret 4 9 ADD Files and Data Safety iae eet iet eee tds Feed tens deese dad 4 9 Program Requirements cis ciet ete e Er e RE e e eb Eee to e aee Pose eee 4 10 43 1 Execution Dime oce gp REPRE nea eie ne nit 4 10 2 3 2 SStokage SDACe stent idee te ette eto pei ie E E 4 11 Program Lamitations aee tete eee ete t idee nepote eta deste sedi tonii e eet 4 11 Details on Graphics Mode sssssssssseeseeee eene enne enne enne ener n rne nennen enne 4 12 4 5 Graphics Environments doenn ertet e e ove T EE Pe Pede ies 4 12 4 52 Howito gethelpespssstoriagufsstestessnsteusdemueegtsedlsestkturnl 4 15 4 5 3 Dialogue Boxes and their Contents sss ene 4 15 4 5 4 The standard Buttons in a Dialogue Box 4 17 4 5 5 Selecting several Alternatives from a List sss eene 4 17 4 5 6 Entering a Vector o
59. of shown on the screen No other changes need be made Another possibility is to set the device to DUMMY which will make all display commands execute without generating displays The DESTINATION is always set to SCREEN when Postresp starts up regardless of the status it may have been set to in a previous run EXAMPLES The following options are default when Postresp starts up with a new database SET DISPLAY COLOUR ON SET DISPLAY DESTINATION SCREEN SET DISPLAY DEVICE TX4014 15 16 54 if running in line mode SET DISPLAY DEVICE X WINDOW if running in graphics mode SET DISPLAY WORKSTATION WINDOW 60 120 40 100 SESAM Program version 6 2 SET DRAWING 15 DEC 2007 CHARACTER TYPE HARDWARE SOFTWARE FONT SIZE ABSOLUTE width RELATIVE factor DRAWING FONT TYPE SIMPLE GROTESQUE ROMAN NORMAL ROMAN ITALIC ROMAN BOLD FRAME ON OFF PURPOSE GRID Set attributes of drawings PARAMETERS ON OFF Postresp 5 137 CHARACTER TYPE The character type can be either SOFTWARE i e scalable or HARDWARE i e FONT SIZE width factor FONT TYPE FRAME GRID fixed Select the font size Set font width Set scaling factor Select the font to be used The list of fonts may be machine dependent Turn the frame of the display and plot on off The framed plot is roughly A4 size on
60. of the plot file depends on the plot format used Several formats are available including Post script It is possible to use more than one plot file during the same Postresp session but only one can be open at a time Postresp has been designed to protect the user against loss of valuable data Thus for some of the errors that may occur Postresp will close the database file before exiting the program It is however not always possi ble to catch a program crash and close the database file properly when it happens If the database file has been corrupted the information may be reconstructed by use of the journal file It is therefore recommended to take good care of the journal files include comments etc It can also be a good idea to take backup copies of the journal and database file at regular intervals 4 5 Program Requirements 4 3 1 Execution Time The execution time depends on which commands the user gives and cannot be generalized The Create Long Term Response command is the most time consuming and the user should be careful about requesting long term responses calculated for all responses at the same time SESAM Postresp Program version 6 2 15 DEC 2007 4 11 4 3 2 Storage Space The initial size of the database ahead of any definitions or reading a Results Interface File is about 250 Kil obytes For a small to a medium size run the database may grow to Mbyte Huge runs can require up to 3 Mbyte storage space 4 4 P
61. printing the spectrum or when short term statistics is calculated The internal numbering system is given in Section 3 11 In addition to the reference number the program offers a descriptive text for identification of the spectrum and for information of what basic variables the spectrum is created from To generate a spectrum the user must input the name of the response variable for which the spectrum shall be created Further input is for which main wave direction and which wave spectrum the response spectrum is to be calculated The user also has to input whether long crested sea or short crested sea with a given wave spreading function shall be used SESAM Postresp Program version 6 2 15 DEC 2007 3 5 The program offers a wildcard alternative on each level in the command structure so the user may for instance have the response spectra calculated for all response variables all wave directions and for all wave spectra If short crested sea is used and the user has a large number of response variables or wave direc tions please be aware of the CPU consumption which may be high If the number of response variables is ng the number of wave directions m and the number of wave spectra sea the total number of response spectra generated will be Not ng Myd A Esea Two examples are given below One with long crested sea and one with short crested sea and a wave spread ing function called COS2 The response spectra are requested for HE
62. response spectrum based on three different inputs e Given a response level the probability of exceedance will be printed e Given a sea state duration the number of zero upcrossings the probability of exceedance and an estimate of the most probable largest response level will be printed Given a probability of exceedance the corresponding response level will be printed The short term statistics 1s given as a single amplitude response 2 8 Long Term Response The long term response calculation offered includes long term calculation with either Nordenstrom s model or a scatter diagram Speed reduction can be taken into account in long term response calculations The print from the long term calculation includes response levels for given probability levels the Weibull parameters estimated when fitting the short term parameters to a Weibull distribution and the response lev els for up to 5 return periods All of these are printed for each wave direction calculated and if requested with all wave directions included The display or plot offered is either a function of the probability level or a function of the wave direction If long term responses have been calculated for a set of sectional forces and these section numbers increase continuously from 1 to n Postresp also offers a long term sectional force diagram similar to the option in DISPLAY SECTIONAL FORCE DIAGRAM The long term response is given as a single amplitude re
63. sequence number on the sectional forces Froude Optional Froude number Only if several forward speeds is available Postresp SESAM 5 96 15 DEC 2007 Program version 6 2 DISPLAY SHORT TERM RESPONSE SHORT TERM RESPONSE _ body number PURPOSE To display one or several short term responses created by the program A maximum of 7 short term responses can be displayed together PARAMETERS body Optional body identification Only available if DEFINE PRESENTATION OPTION SI MULTANEOUS BODIES is set to ALL number Reference number of the short term response SESAM Program version 6 2 15 DEC 2007 DISPLAY SN CURVE SN CURVE name PURPOSE To display one or several SN curves PARAMETERS name Name of the SN curve Postresp 5 97 Postresp 5 98 15 DEC 2007 DISPLAY SPECIFIC POINT XY PLANE SPECIFIC POINT name XZ PLANE YZ PLANE PURPOSE To display one or several specific points in a given plane PARAMETERS name Name of the point XY PLANE _ The points are displayed in the xy plane XZ PLANE The points are displayed in the xz plane YZ PLANE The points are displayed in the yz plane SESAM Program version 6 2 SESAM Program version 6 2 15 DEC 2007 DISPLAY SPEED REDUCTION CURVE SPEED RECUTION CURVE name PURPOSE To display one or several speed reduction curves PARAMETERS name N
64. shape A single wave spectrum is generated SESAM Postresp Program version 6 2 15 DEC 2007 5 49 CREATE WAVE SPECTRUM OCHI HUBBLE WAVE SPECTRUM name txt OCHI HUBBLE SINGLE ec HsS TpS GamS HsW TpW GamW PURPOSE To create wave spectra based on a Ochi Hubble spectrum type The Ochi Hubble wave spectrum is a two peak spectrum divided in two parts each reminiscent of the Gen eral Gamma spectrum modelling one contribution from swell and one for wind generated sea PARAMETERS name Name of the spectrum txt Descriptive text of the spectrum HsS Significant wave height for the swell part TpS Peak period for swell part GamS Shape parameter for swell part HsW Significant wave height for the wind part TpW Peak period for wind part GamW Shape parameter for wind part NOTES The application of this spectrum is restricted to creating response spectrum and computation of short term statistics along with print and display of the spectrum Long term statistical processing involv ing this spectrum is not offered in Postresp Fatigue calculations based on this spectrum can be done in Framework The main purpose in Postresp in this case is to supply Framework with some display and print functionality EXAMPLES CREATE WAVE SPECTRUM OCHIHUB Ochi Hubble spectrum OCHI HUBBLE SINGLE 2 20 1 5 6 10 3 OCHI HUBBLE Postresp 5 50
65. shape to a wave scatter diagram The assignment may be to the total scatter dia gram or to a selected part of the diagram The assignments will override the previous assignments It is only possible to assign a wave spectrum shape to the total sea state area if the wave statistics is described through a Nordenstr m model PARAMETERS name PIERSON MOSKOWITZ JONSWAP GENERAL GAMMA gam sma smb lsp nsp ALL PART hsl hsu Name of the wave statistics model Wave spectrum of type Pierson Moskowitz default Wave spectrum of type JONSWAP Wave spectrum of type general gamma Enhancement factor y of JONSWAP spectrum Left width oa of JONSWAP spectrum Right width ob of JONSWAP spectrum l parameter in the general gamma spectrum n parameter in the general gamma spectrum Wave spectrum shape will be assigned to the total area of the wave statistics model Wave spectrum shape will be assigned to an area of the scatter diagram limited by the square made of the parameters HSjywer HS jpper and Tsjawer TS upper Lower limit of the significant wave height Hs Upper limit of the significant wave height Hs Postresp SESAM 5 10 15 DEC 2007 Program version 6 2 tzl Lower limit of the zero upcrossing wave period Tz Lower lim it of the mean period T1 when ISSC spectrum tzu Upper limit of the zero upcrossing wave period Tz Upper limit of the mean period T1 when ISSC spectrum NOTES If the command is not
66. their probability of occurrence These values may be given through an approach based on Nordenstram s theory or by specifying a scatter diagram directly The wave statistic models are given names and may be assigned to correct wave direction independently of each other The Nordenstrom model is formulated and based on the fact that data for stationary sea state is usually given in terms of visually estimated periods T and visually estimated wave heights H A further description of the theory supporting the model and the different parameters involved is presented in Appendix B The scatter diagram type offered is a H T diagram where the probability of each non zero box in the dia gram must be specified The diagram may be identical for all wave directions omnidirectional or it may be wave direction dependent Scatter diagrams may be read from an external file provided that the file is given in the Results Interface File format The ISSC scatter diagram offered is a H T diagram and is required for the ISSC wave spectrum Two standard scatter diagrams are now automatically generated in Postresp SESAM Postresp Program version 6 2 15 DEC 2007 2 5 DNV NA DNV North Atlantic e DNV WW DNV World Wide trade The wave statistics may be printed Neither display nor plot capabilities are available Postresp SESAM 2 6 15 DEC 2007 Program version 6 2 2 5 Response Spectra A response spectrum may be either an auto spectrum
67. tion dir Main wave direction Wild card specification is available spec Name of the wave spectrum to be used in the calculation Wild card specification is available sprea Name of the wave spreading function to be used in the calculation when short crest ed sea NONE Long crested sea no wave spreading function Postresp SESAM 5 32 15 DEC 2007 Program version 6 2 CREATE RESPONSE SPECTRUM sprea RESPONSE SPECTRUM resp dir spect NONE PURPOSE To create response spectra of type auto spectra For each response variable for each global wave direction and wave spectrum a new response spectrum is created The user may select several response variables sev eral wave directions wave spectra and one wave spreading function if short crested sea is assumed The program will generate internal numbers on each response spectrum which will be used as reference later The different numbers and a descriptive text for each response spectrum may be achieved by using the overview alternative under the PRINT RESPONSE SPECTRUM command PARAMETERS resp Name of the response variable for which the response spectrum is to be calculated Wild card specification is available dir Main wave direction Wild card specification is available spec Name of the wave spectrum to be used in the calculation Wild card specification is available sprea Name of the wave spreading function to be used in the calcula
68. user wants to calculate a new long term response for a previously used response variable he either has to use the CHANGE command or to delete the existing results Before generating the long term response the user must assign wave statistics models and probability of occurrence to each wave direction to be included If the sum of probabilities is equal to 1 Postresp will automatically calculate long term probability for all wave directions included The wave spectrum shapes and wave spreading function used within the wave statistics models are to be assign on beforehand to each wave statistics model A Pierson Moskowitz spectrum will be assumed if not specified otherwise To generate a long term response the user only has to input the name of the response variable and the main wave directions for which the long term response shall be created The program offers a wildcard for selecting the response variables and for the main wave directions The necessary computing time in Postresp is normally short but the long term calculations are the most CPU consuming parts of Postresp so the user should use the wildcard with care One example is given below a short crested sea condition with a wave shape as Pierson Moskowitz by default and spreading function called COS2 The long term responses are requested for HEAVE and PITCH motion all wave directions are taken into account and a Nordenstrem wave statistics model called NORI is used SESAM Postre
69. user also may combine any transfer functions The program DOES NOT check what type of responses the user combines Figure 3 2 shows a sectional force combination where the transfer function for the total split force in point A of section number 3 is established Postresp SESAM 3 4 15 DEC 2007 Program version 6 2 SWL Figure 3 2 Sectional force in point A of section number 3 The equation used is TRA py TRCpy z TRC yy 3 2 where TRA the resulting transfer function in point A TRC the transfer functions at the origin of the global coordinate system in the free surface SWL Z the moment arm about the y axis The combined transfer functions may be used as any other transfer function in short or long term statistical calculations The command for the force combination given above is CREATE RESPONSE VARIABLE SPLITSP Split force in section A GENERAL COMBINATION SECL31 1 SECL35 1 5 3 3 Calculation of Response Spectra A response spectrum is generated by multiplying the square of the transfer function with a given wave spec trum The calculation may take into account short crested sea by giving each wave direction included a specified weight The weight is generated through a wave spreading function usually a cosine function The response spectra are given as double amplitude response Each response spectrum is given a reference number This reference number will be used when plotting or
70. 20074 C 25 ME Create Workability Figure C 27 CREATE WORKABILITY Postresp SESAM C 26 15 DEC 2007 Program version 6 2 C6 DEFINE Menu ME POSTRESP 6 2 04 File Assign Change Create eSa Delete Display Print Run Select Set Help Constants 2 slele ak Range Long Term Probability Presentation Option Return Period Speed Reduction Structure Orientation Figure C 28 DEFINE pulldown menu ME Define Constant x Define Return Period Gravity 9 8 Periods in Years Water Density Hs Tolerance Tz Tolerance Frequency Tolerance Periods in Years eee os Are Cancel Include Exclude Overwrite Insert before Clear Help ME Define Frequency Range Lower Frequency 13962 OK Appl Cancel Upper Frequency pply ance Figure C 29 DEFINE CONSTANTS FREQUENCY RANGE RETURN PERIOD SESAM Postresp Program version 6 2 15 DEC 20074 C 27 ME Define Long Term Probability x Define Speed Reduction Probability Exponent Probability Exponent Cancel Include Exclude Overwrite Insert before Clear Help ME Define Structure Orientation Orientation R ep ane OK Apply Cancel ME Define Presentation Option Simultaneous Bodies Abscissa Axis Angular Frequency v Response Variable Ordinate Values Amplitude Ordinate Units R adians Second Order Graph Direction to be fixed First Direction z Contour Levels Low High Step OK
71. 3 POSTRESP 6 1 10 mix File Assign Change Create ETE Delete Display Print Run Select Set Help Constants 2 ele Frequency Range Long Term Probability Presentation Option Return Period M REAWAWK s Speed Reduction tr ma Structure Orientation xx dn n n ttt tk ee FEE dee c t em eee xt n xtxhx x t t t t t t t t t det n nn dtt em tttrxw x ctt nk tr t t t rer dtt en ttttx x ttt t hn k t t t tt tt tt t tt t tt t r tt ott tt te t t t Ek x tk ttt x xt ttt tty t t uk de e t treer ttt Re t t Wt kd kd dd Rd dd dd Rd EERE EERE EA A EE EE EE EE EE EE EE EE EE EE EEA POSTRES P OF o 5 o9 Postprocessor for General Response Statistics dodo Rd UR UE UE UU EE EE EA AA Marketing and Support by DNV Software Figure 4 7 The Postresp graphics environment If the main window is iconised all the open dialogue boxes disappear into the icon They pop up again when the main window is popped up In addition to this the graphics environment consists of Pull down menus These are pulled down from the items in the main menu They are activated by clicking on an item in the main menu with the left mouse button or by holding the left mouse button down on an item in the main menu Similarly some of the items in a pulld
72. 6 Ochi Hubble Spectrum The six parameter Ochi Hubble spectrum consists of essentially two parts one for the lower frequency com ponents of the wave energy and the other covering the higher frequency components Each component is expressed in terms of three parameters and the total spectrum is written as a linear combination of the two Thus double peaks present in a wave energy density can be modelled with this formulation e g a low fre quency swell along with the high frequency wind generated waves The spectrum m be expressed by 2 A e os HL Sa 0 ly TO eer B 25 j 1 Postresp SESAM B 6 15 DEC 2007 Program version 6 2 where a B 26 4 and where index j 1 corresponds to the lower frequency components and j 2 to the higher frequency components H Ogj A are significant wave height modal frequency of the spectral peak and shape factor of component j respectively The spectrum is illustrated in Figure B 3 If in either spectral component the values of the parameters Hj and mg are held constant controls the shape or in particular the sharpness of the spectral peak Thus is called the spectral shape parameter If A I and A 0 we obtain the Pierson Moskowitz spectrum model In the general formulation of Equation B 25 the equivalent significant height H is obtained from 2 H JH Hp B 27 on the assumption of narrowbandedness of the entire spectrum Generally the value of 4 i
73. AVE and PITCH motion wave direc tions 0 45 and 90 degrees and for a wave spectrum named FRPM11 with H 1 0 and T 10 0 CREATE RESPONSE SPECTRUM CREATE RESPONSE SPECTRUM EAVE PITCH 0 45 90 FRPM11 NONE EAVE PITCH 0 45 90 FRPM11 COS2 Hi Hi This will generate a total of 12 response spectra Spectrum number 1 3 HEAVE 0 45 and 90 degrees and short crested sea Spectrum number 4 6 PITCH 0 45 and 90 degrees and short crested sea Spectrum number 7 9 HEAVE 0 45 and 90 degrees and wave spreading function COS2 Spectrum number 10 12 PITCH 0 45 and 90 degrees and wave spreading function COS2 3 4 Calculation of Short Term Response The short term response is calculated for a given response spectra The response spectra are generated by multiplying the square of the transfer function with given wave spectra for a set of zero upcrossing periods The calculation may take into account short crested sea by giving each wave direction included a specified weight The weight is generated through a wave spreading function usually a cosine function The short term response is given as the double amplitude response per significant wave height Each short term response is given a reference number This reference number will be used when plotting or printing the spectrum The internal numbering system is given in Section 3 11 In addition to the reference number the program offers a desc
74. B 9 B 34 B 35 B 36 B 37 B 38 B 39 Postresp SESAM B 10 15 DEC 2007 Program version 6 2 B 40 Tps S TF Bl Peak enhancement factor B 41 c High frequency exponent B 42 N N Spectral width exponent B 43 M M B 1 7 4 Swell dominated sea Primary peak Significant wave height B 44 Eu 2 Hs Hs 1 420 e 4420 Spectral period SESAM Program version 6 2 Peak enhancement factor High frequency exponent Spectral width exponent Secondary peak Significant wave height Spectral period Postresp 15 DEC 2007 B 11 B 45 Tpp Tp B 46 Hs 27 Hs A Seas ey KOCEK I a B 47 N KOVHs K00 B 48 M M0 B 49 2 Hs Hs je 420 e 4 420 Postresp SESAM B 12 15 DEC 2007 Program version 6 2 B 50 Hs 16 S0 1 e 5 0 4 rps 16 80 0 e 9 04 G0 Hs e Peak enhancement factor B 51 KI High frequency exponent B 52 N N Spectral width exponent B 53 Hs M 2 M0 1 B2 e P B 1 7 5 The combined spectrum for wind and swell Thus the total doubly peaked spectrum is the sum of the generalized Jonswap spectrum for the primary peak and the generalized Jonswap spectrum for the secondary peak each dependent on the parameters Hs Tp M N and y or Hs Tp M N and y These constants are in turn functions of the basic parameters Hs and Tp for the total spectrum Hs is the significant wa
75. CH motion wave directions 0 45 and 90 degrees and for a Pierson Moskowitz spectrum with a T range from 5 0 seconds to 15 0 seconds with an increment of 0 5 seconds CREATE SHORT TERM RESPONSE HEAVE PITCH 0 45 90 PIERSON MOSKOWITZ 1 21 NONE CREATE SHORT TERM RESPONSE HEAVE PITCH 0 45 90 PIERSON MOSKOWITZ 1 21 COS2 This will generate a total of 12 short term responses Short term response number 1 3 HEAVE 0 45 and 90 degrees and short crested sea Short term response number 4 6 PITCH 0 45 and 90 degrees and short crested sea Short term response number 7 9 HEAVE 0 45 and 90 degrees and wave spreading function COS2 Short term response number 10 12 PITCH 0 45 and 90 degrees and wave spreading function COS2 3 5 Calculation of Long Term Responses The long term response is calculated based on a long term description of the sea either through a scatter dia gram or through an analytic model based on Nordenstrem s theory The long term response calculation uses the short term parameters calculated for each response spectrum with a given H and T value Short crested sea may also be taken into account The long term response is given as the single amplitude response Each long term response calculated is referred to through the original response variable used No internal numbering system is introduced This also influences the storage of the long term responses If the
76. COSINE POWER ec power PURPOSE To create energy spreading for elementary wave directions by a cosine of power n PARAMETERS name txt power Name of the spreading function Descriptive text of the spreading function Power of the cosine function given as an integer value Default is 2 EXAMPLES CRI EATI E WAV E SPRI EADING FUNCTION COS2 Cosine squared COSINI E POW I ER 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 55 CREATE WAVE SPREADING FUNCTION USER SPECIFIED WAVE SPREADING FUNCTION name tx USER SPECIFIED dir fact PURPOSE To create energy spreading for elementary wave directions with user defined weights on each direction The sum does not need to be equal to 1 since the program will normalize the weights when using the spreading function PARAMETERS name Name ofthe spreading function txt Descriptive text of the spreading function dir Relative direction to the main wave direction in use The range is if spanning over 180 de grees from 90 degrees to 90 degrees fact Weight for each elementary wave direction relative to the main wave direction Postresp SESAM 5 56 15 DEC 2007 Program version 6 2 CREATE WAVE STATISTICS ISSC SCATTER DIAGRAM WAVE STATISTICS name NORDENSTROM SCATTER DIAGRAM PURPOSE To create long term description of di
77. CTRU Ei ESPONSE VARIABLE Es a zi HORT TERM RESPONSE N CURVE PECIFIC POINT CI YUULUUUUULU goggoggo go ANANAAARAAARAAAARAAAAARAAARAAAAAAAAAAAAaAAaAAA a zi Don o IJ DW PEED REDUCTION DATA Postresp 5 3 Postresp SESAM 5 4 15 DEC 2007 DELETE WAVE SPECTRUM DELETE WAVE SPREADING FUNCTION DELETE WAVE STATISTICS DELETE WORKABILITY ANALYSIS Ij DISPLAY DISPLAY LONG TERM RESPONSE DISPLAY MATRIX DISPLAY REFRESH DISPLAY RESPONSE CO SPECTRUM DISPLAY RESPONSE SPECTRU DISPLAY RESPONSE VARIABLE DISPLAY SECTIONAL FORCE DIAGRAM DISPLAY SHORT TERM RESPONSE DISPLAY SN CURVE DISPLAY SPECIFIC POINT DISPLAY SPEED REDUCTION CURVE DISPLAY WAVE SPECTRU DISPLAY WAVE SPREADING FUNCTION tj H E ij EH EXIT PLOT READ Hi H El ij pH Hi Li FA ra PU COMMAND INPUT FIL LINE MODE PROGRAMMING MOD STATUS LIST SUPPORT HE D Es U Gl El Ut pi rot Gl H Ed Dd El U p Hj t PRINT DATASET PRINT LIMITATIONS PRINT LONG TERM FATIGUE ERM RESPONS Lr PRINT MATRIX ESPONSE CO SPECTRUM ESPONSE SPECTRU ESPONSE VARIABLE ECOND ORDER STATISTICS l ERM FATIGUE HORT TERM RESPONSE HORT TERM STATISTICS CIFIC POINT ED
78. EC 2007 Program version 6 2 DELETE LONG TERM RESPONSE RESPONSE VARIABLE respt SLAMMING point LONG TERM RESPONSE PURPOSE To delete long term response for a given response variable or long term slamming at a specific point PARAMETERS RESPONSE VARIABLE s a term response for a given response variable will be delet ed resp Name of the response variable for which the long term response shall be deleted SLAMMING Long term slamming calculation will be deleted point Name of the specific point where long term slamming shall be deleted SESAM Postresp Program version 6 2 15 DEC 2007 5 75 DELETE RESPONSE CO SPECTRUM RESPONSE CO SPECTRUM number PURPOSE To delete a generated response cross spectrum PARAMETERS number Reference number of the response cross spectrum This reference number is generated by the program and may be examined by the PRINT OVERVIEW RESPONSE CO SPECTRUM command Postresp SESAM 5 76 15 DEC 2007 Program version 6 2 DELETE RESPONSE SPECTRUM RESPONSE SPECTRUM number PURPOSE To delete a generated response spectrum PARAMETERS number Reference number of the response spectrum This reference number is generated by the pro gram and may be examined by the PRINT OVERVIEW RESPONSE SPECTRUM com mand SESAM Postresp Program version 6 2 15 DEC 2007 5 77 DELETE RESPONSE VARIABLE RESPONSE VARIABLE name
79. ESAM Program version 6 2 SESAM Program version 6 2 PRINT SPECIFIC POINT SPECIFIC POINT namet PURPOSE 15 DEC 2007 Postresp 5 125 To print specific points defined in Postresp or read from the Hydrodynamic Results Interface File G file PARAMETERS name Name of the point Postresp 5 126 15 DEC 2007 PRINT SPEED REDUCTION SPEED REDUCTION namet PURPOSE To print speed reduction curves PARAMETERS name Name of the curve SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 127 PRINT WAVE SPECTRUM name DUMP SPECTRUM name WAVE SPECTRUM PURPOSE To print defined and calculated wave spectra Only the spectrum characteristics such as the spectrum period and moments will be printed unless the user asks for a dump Note that for a general gamma spectrum only the user input are available due to the fact that the wave spec trum it self will not be calculated PARAMETERS name Name of the spectrum ALL All wave spectra are printed DUMP SPECTRUM The selected wave spectrum name will be dumped i e spectrum ordinates for 201 frequencies will be printed Postresp 5 128 PRINT WAVE SPREADING FUNCTION 15 DEC 2007 WAVE SPREADING FUNCTION name space PURPOSE To print energy spreading for elementary wave directions SESAM Program version 6 2 PARAMETE
80. Francais Du Petrole 9 Naess A and Ness GM Second order sum frequency response statistics of tethered platforms in random waves Accepted for publication in Applied Ocean Research Department of Civil Engineering The Norwegian Institute of Technology Postresp SESAM REFERENCES 2 15 DEC 2007 Program version 6 2 10 Winterstein S R 1988 Nonlinear vibration models for extremes and fatigue J Engrg Mech ASCE 114 10 1772 1790 11 Model for a doubly peaked wave spectrum Report STF22 A96204 SINTEF Civil and Environmental Engineering Trondheim Norway February 1996
81. INDOWS PRINTER HPGL 2 CGM BINARY FORMAT PURPOSE Set the plot format The actual list of available devices depend on the installation Some but not necessarily all of these could be available PARAMETERS SESAM NEUTRAL Sesam Neutral format This is the default format POSTSCRIPT PostScript format PostScript is a trademark of Adobe Systems Incorporated Note that this requires access to a printer that accepts PostScript files HPGL 7550 HP 7550 plotter file format WINDOWS PRINTER Send plot directly to the default printer defined in Windows HPGL 2 HP GL 2 plotter file format CGM BINARY CGM binary plot file format can be imported into word processors EXAMPLES The following option 1s default when Postresp starts up with a new database SET PLOT FORMAT SESAM NEUTRAL Postresp SESAM 5 146 15 DEC 2007 Program version 6 2 SET PRINT CSV FILE DESTINATION FILE SCREEN PRINT FILE prefix name SCREEN HEIGHT _ nlines LANDSCAPE PAGE ORIENTATION PORTRAIT PURPOSE Set options that affect print PARAMETERS DESTINATION CSV FILE FILE SCREEN FILE prefix name SCREEN HEIGHT nlines PAGE ORIENTATION LANDSCAPE PORTRAIT NOTES To set the print destination to screen or print file ordinary text file or comma separated values file Direct print to the comma separated values print file Direct print
82. IONS ON OFF MARKER CROSS DEFAULT DELTA DIAMOND NABLA PLUS SQUARE MARKER TYPE line MARKER SIZE size PURPOSE Set options controlling how lines are drawn and marked PARAMETERS LINE TYPE line MARKER MARKER TYPE MARKER SIZE size Controls how lines are drawn Only six lines can be controlled A line number from 1 to 6 Turn usage of markers on off Control the marker type for up to six lines Set the size of the markers The size of the markers SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 141 SET GRAPH XAXIS ATTRIBUTES EXPONENTIAL FIXED DECIMAL FORMAT GENERAL INTEGER FREE XAXIS ATTRIBUTES LIMITS FIXED xmin xmax LINEAR SPACING LOGARITHMIC DEFAULT TITLE SPECIFIED xtitle PURPOSE Set options controlling the attributes of the x axis in a graph PARAMETERS DECIMAL FORMAT LIMITS SPACING TITLE EXAMPLES Controls the presentation of numbers labelling the x axis The numbers can be pre sented in EXPONENTIAL format in FIXED format as INTEGERs or in GENER AL free format Controls the limits of the x axis These can either be FREE i e determined by the data that are being presented or FIXED to the min value lt xmin gt and the max val ue lt xmax gt Controls the spacing of numbers along the axis The axis can have a LINEAR sp
83. M USER SPECIFIED TESTSPEC 0 1 1 0 2 1 0 3 1 0 4 1 0 5 1 0 6 1 0 7 1 0 8 1 0 9 1 1 0 1 Creates a constant wave spectrum defined in the angular frequency area of 0 1 to 1 0 Postresp SESAM 4 28 15 DEC 2007 Program version 6 2 4 6 10 Setting and clearing Loops in a Command When a command is completed Postresp will by default go back to the main prompt If a command is to be repeated many times in slightly different versions it can be desirable to go back to an intermediate level instead of to the main prompt This is accomplished by typing the text LOOP at the point where the com mand is to be repeated The loop is removed by typing END at the loop point or by aborting the command using the double dot An obvious example in Postresp is in the CREATE RESPONSE SPECTRUM command Often many spec tra are created in sequence in order to get control of the identification numbers It then makes sense to set a loop just after CREATE RESPONSE SPECTRUM In the example below 3 response variables 3 wave directions and all wave spectra is selected The n first response spectra will be for long crested sea and the n to 2 n for short crested sea using a wave energy spreading function named COS2 CREATE RESPONSE SPECTRUM LOOP SURGE 045 90 NONE SURGE 045 90 COS2 SWAY 0 4590 NONE SWAY 04590 COS2 HEAVE 045 90 NONE HEAVE 045 90 COS2 END 4 6 11 Inserting a Comma
84. MSINGLE Hs 8m Tz 10s PIERSON MOSKOWITZ SINGLE 8 10 CREATE WAVE SPECTRUM PM Tz 10 to Tz 20 PIERSON MOSKOWITZ FULL RANGE 10 20 0 5 SESAM Postresp Program version 6 2 15 DEC 2007 5 51 CREATE WAVE SPECTRUM TORSETHAUGEN WAVE SPECTRUM name txt TORSETHAUGEN FULL RANGE tp min tp max incr SINGLE hs tp PURPOSE To create wave spectra based on a Torsethaugen spectrum type The Torsethaugen spectrum is a two peak wave spectrum which can be applied for short term statistics The spectrum can also be printed and displayed PARAMETERS name Name of the spectrum txt Descriptive text of the spectrum FULL RANGE Full range calculation of TORSETHAUGEN spectra Le wave spectra with Hs equal to 1 0 and different Tp values given as a range will be generated This alter native will create internal names which will be prfx where prfx is the first 4 letters of the name given and is an integer number in increasing order see Section 3 3 tp min Minimum value of Tp for full range calculation tp max Maximum value of Tp for full range calculation incr Increment between tpmin and tpmax Total number of generated spectra will be maximum minimum increment 1 SINGLE A single wave spectrum is generated hs Significant wave height Hs tp Peak period Tp NOTES This spectrum is not included in the long term statistics T
85. Ni irm es 8 DR K m m a b Vo ry y bt 2 ale b UT B 140 in which y is the incomplete Gamma function B7 3 Short Term Fatigue Linear Model In this case the stress range is assumed to have Rayleigh distribution with parameters based on the spectral moments My and M M defined as in Equation B 69 In this case the parameters a b and vg are as fol lows 1 M b 2 a BM vo F a B 141 0 B7 4 Long Term Fatigue Sum over Seastates A long term fatigue analysis focuses on the total damage D contributed by all seastates and all headings The preferred calculation method is to evaluate the foregoing short term results over all such seastate head ing cases i 1 N and weight by the relative frequencies pj of these various cases Dios Y piDi Ta Y p DR K m a b Voi B 142 1 1 Thus the same damage rate function DR should be calculated for all seastate heading cases As Equation B 142 indicates each of these will typically have different parameters a b and vg These should be eval uated from Equation B 141 It may also be useful to consider some output that reflects not only the total damage D but the relative contributions from the different seastates as well B7 5 Long Term Fatigue from Long Term Distribution Finally as an alternative to Equation B 142 the long term fatigue damage can be estimated directly from the long term Weibull stress distribution already fitted 1n P
86. ON reco esee nahe p ta eoru n RESP Se xp rn peru nihes opone De pix a pre REN Aene a 5 1 5 Commands for Postresp 5 aU T EAT YT CIE P a Erg rS EM tha 5 2 5 2 Frequency domains ian en t endi tes e e Mead en n Er PER De EP Ee nae 5 2 APPENDIX A TUTORIAL EXAMPLES eere esee eee eene eee seen se eee eo ses teen aee eee aa see A 1 AT BLOATING BARGE vette A 1 APPENDIX B THEORY AND FORMULATION esssssssservsvssssssvseenssvvnsessnnsnssssnsnssseessnseeeee B 1 B1 SHORT TERM DESCRIPTION OE SEA gassenes melsa B 1 B 1 1 Wave Energy Spreading FUnction cccccescccsseesecessceeeeseeeseceseceeeeseecsecsaeceseseeeeeeeeaeenaees B 1 B1 Pierson Moskowitz Spectrum sannan E a E T Ee B 3 B3 JONSWAP Spectr a cent eenen n edes E E Ee ede agp es EE AATAS B 3 B 14 Gamma Spectrum iege one eap ecd a a a ERR e aia iai aia tes B 4 B L5 SSE Spect tarn n Ro D Ae AOE SENET S Aaaa E tees aa aeg EER EE a a Uis cante B 5 B 1 6 Ochi Hubble Spectrum eee eceeccsseesceseesecececesseeseeseceeceaecaeeaeeeeeesecaecaaeeaeeaeeeeeeeaeeateas B 5 B 1 7 Torsethaugen Spectrum sssssssssseeseeseeen eene enne enne nennen innen nennen nnne B 6 B2 LONG TERM DESCRIPTION OF SEA cionis ame elena B 13 B2 1 Statistical Model inen ee er e EP Ier ra ee teme B 13 B2 2 Distribution of Wave Height sese enne eene enne nnne B 13 B2 Transformation Parameters essen ener eene B 13 B3 TRANSFER FUNCTIONS peto cota oa B 15
87. ON MOSKOWITZ FULL 5 15 0 5 Create a point named SP on the barge where an absolute combined motion response will be created The point is located on the section number 3 used by the analysis program Wadam CREATE SPECIFIC POINT SP 12 0 0 1 5 Create a wave statistics model for describing the long term condition of the sea The wave statistics model is based on Nordenstrom s theory and named NORI CREATE WAVE STAT NORLI NORDENSTROM MODEL FOR WAVE STATISTICS I NORDENSTROM duo 4119 1 0 25 0 63 6 5 3455 1 35 0 85 0 85 8 5 35986 1 1 2 05 1 13 1055 1385 0X 75 343 1 56 12 5 029 0 35 5 0 1 82 14 5 005 0 2 6 15 2 02 16 5 001 0 0 6 3 1 86 18 5 0028 0 35 2 0 0 85 20 LOG NORMAL 3 2 83 0 44 0 12 11 21 0 1 68 0 75 0 1429 Create a global combined motion response in the predefined point SP and a general force load combination in section 3 The new response variables are called ADISZSP and SPLITSP de do de do oe CREATE RESPONS VARIABLE ADISZSP COMBINED MOTION SP DISPLACEMENT ABSOLUTE Z CREATE RESPONS VARIABLE SPLITSP GENERAL COMB SECL31 1 SECL35 1 5 Create a response spectrum for the response variables HEAVE and PITCH for the main wave directions 0 45 and 90 degrees and for both long and short crested sea The wave spectrum used is SESAM Postresp
88. ONG TERM FATIGUE LONG TERM FATIGUE resp dirt sn curve PURPOSE To create long term fatigue for a selected set of response variables and a set of global wave directions The long term fatigue calculations will be based on a scatter diagram using a Rayleigh distribution for each cell and a named SN curve Both the partial damage from each cell and total damage are calculated The wave spectra and spreading functions used will be those assigned to the wave scatter diagram PARAMETERS resp Name of the response variables for which the long term fatigue is to be calculated Wild card specification is available dir Main wave direction Wild card specification is available sn curve Name of the SN curve to be used EXAMPLES CREATE LONG TERM FATIGUE ONLY STRESS ONLY 0 0 30 60 90 0 120 0 150 180 0 210 0 240 0 270 0 300 0 330 DNVC I Postresp SESAM 5 30 15 DEC 2007 Program version 6 2 CREATE LONG TERM RESPONSE LONG TERM RESPONSE RESPONSE VARIABLE respt dirt PURPOSE To create long term responses for either a selected set of response variables or through slamming calcula tions for standard motions in a specified point both for a selected set of global wave directions The wave statistics model may be of type a Nordenstram model or a scatter diagram which is assigned to each wave direction selected The wave spectra and spreading functi
89. POSTRESP 6 1 01 26 NOV 1993 Response spectra for HEAVE short crested sea Response Spectrum 0 N Pi m gt ved c o D 2 Q c o c Lu 1 0 Angulor Frequency rad s A 7 HEAVE Dir 0 0 FRPMii COS2 Identical parameters 8 HEAVE Dir 45 0 FRPM1 COS2 Depth 250 0 0 9 HEAVE Dir 90 0 FRPM COS2 SESAM Postresp Program version 6 2 15 DEC 2007 A 19 SESAM POSTRESP 6 1 01 26 NOV 1993 Response spectra for PITCH long crested sea Response Spectrum o N 2 E pr a c g v 2 o c o c Lu 1 0 1 2 Angulor Frequency rad s PITCH Dir 0 0 FRPM11 Identical parameters PITCH Dir 45 0 FRPMI1 Depth 250 0 PITCH Dirz90 0 FRPMII Postresp SESAM A 20 15 DEC 2007 Program version 6 2 SESAM POSTRESP 6 1 01 26 NOV 1993 Response spectro for PITCH short crested sea Response Spectrum 0 N gt z 2 E pr o c o D 2 o Q o c m 1 0 1 2 Angulor Frequency rod s 4 10 PITCH Dir 0 0 FRPMIiI COS2 Identical parameters at 44 PITCH Dir 45 0 FRPMi1 COS2 Depth 250 0 El 42 PITCH Dir 90 0 FRPM 1 COS2 SESAM Postresp Program version 6 2 15 DEC 2007 A 21 SESAM POSTRESP 6 1 01 26 NOV 1993 Short term resp for HEAVE long crested sea Short Term Response 0 A N de 2 E pr Q c o D 2 o c o c ui 14 16 Zero upcrossing period s HEAVE DirzO 0 FRPM1 FRPM2 I HEAVE Dir 45 0 FRPMI FRPM2 I HEAVE Dir 90 0 FRPM1 FRPM2 1 Postresp SESAM
90. Parameter values 1 0 0 0 Omega P 0 44611 SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 A 9 Transfer function for first order motion Amplitude of Response Variable Amp Litude eS a 0 8 1 0 1 2 Angulor Frequency rad s A HEAVE Dir 0 0 HEAVE Dir 45 0 B HEAVE Dir 90 0 SESAM Program version 6 2 Postresp A 10 15 DEC 2007 SESAM POSTRESP 6 1 01 26 NOV 1993 Transfer function for first order motion Amplitude of Response Variable o o 2 a a E lt 1 0 1 2 Angutor Frequency rad s A PITCH Dir 0 0 PITCH Dir 45 0 PITCH Dir 90 0 SESAM Postresp Program version 6 2 15 DEC 2007 A 11 SESAM POSTRESP 6 1 01 26 NOV 1993 Transfer function for first order motion Amplitude of Response Vor iab le o ge 3 E a t x 1 0 1 2 Angular Frequency rad s ADISZSP Dir 0 0 ADISZSP Dir 45 0 El ADISZSP Dir 90 0 SESAM Program version 6 2 Postresp A 12 15 DEC 2007 SESAM POSTRESP 6 1 01 26 NOV 1993 Transfer function for first order motion Amplitude of Response Variable o0 p 2 A n lt T ll 1 0 1 2 Angular Frequency rad s ALSPLITSP Dir 0 0 SPLITSP Dir 45 0 Dl SPLITSP Dir 90 0 Postresp A 13 SESAM Program version 6 2 15 DEC 2007 SESAM POSTRESP 6 1 04 26 NOV 1993 Transfer Function for First order motion Amplitude of Response
91. Point Wave Spectrum Wave Spreading Function Refresh Figure C 37 DISPLAY MATRIX pulldown menu ME Display L T R for Response Variable x Display L T R for Response Variable x Response Variable Response Variable HEAVE HEAVE SURGE SURGE SWAY SWAY Abscissa Wave Direction Abscissa Probability Level Log 2 C Log C Wave Direction Wave Direction Cancel DK Apply Cancel Cares eb Canea Figure C 38 DISPLAY LONG TERM RESPONSE RESPONSE VARIABLE SESAM Postresp Program version 6 2 15 DEC 20074 C 33 ME Display L T R Sectional Force Diagram El ME Display Matrix Added Mass Wave Direction Element ij Degree of freedom Probability Level Lower Sequence No Upper Sequence No Cancel ME Display SN curve re STBBBBLE SN curve Name Figure C 39 DISPLAY LONG TERM RESPONSE SECTIONAL FORCE DIAGRAM MATRIX ADDED MASS MATRIX POTENTIAL DAMPING MATRIX TOTAL DAMPING SN CURVE Postresp C 34 SESAM 15 DEC 2007 Program version 6 2 ME Display Response Variable El Wil Display Response Spectrum Order First Order Response Spectrum Variable Name Wave Direction E Display Response Co Spectrum El Response Co Spectrum HE Display Specific Point Cancel Specific Point Plane Bonnen XY Plane x USERPNT2 C xZ Plane C YZ Plane Apply Cancel Cancel Figure C 40 DISPLAY RESPONSE VARIABLE RESPONSE SPECTRUM RESPONSE CO SPECTRUM SPECIFIC
92. RAPH nam2 dirl dir2 freq PURPOSE To display one or several first order response variables or second order response variables in specified type of graph First order response variables are presented as a function of frequency for a given wave direction Second order response variables are presented as a function of two frequencies for two given wave direc tions or as a linear cut in this function If the ordinate value of the first order response variable has been set to the real imaginary part or the ampli tude phase only the first body response variable wave direction and Froude number will be used See DEFINE PRESENTATION OPTION RESPONSE VARIABLE ORDINATE PARAMETERS body SECOND ORDER naml dir Froude SURFACE CONTOUR GRAPH nam2 Optional body identification Only available if DEFINE PRESENTATION OP TION SIMULTANEOUS BODIES is set to ALL Second order response variables will be presented against sum or difference fre quency Name of first order response variable Wave direction for first order response variable Optional Froude number Only if several forward speeds are available Display the functional representation of one second order response variable as a 3D surface Display the functional representation of one second order response variable as a contour plot Display the functional representation of one or more second order response varia ble as a linear cut in the two dimensional funct
93. RS name Name of the function space User input space between each wave direction angle for which the energy spreading function will be printed This space is independent of what the program will use in calculating the re sponse spectra Only asked for if one of the names selected corresponds to a cosine power function SESAM Program version 6 2 15 DEC 2007 PRINT WAVE STATISTICS WAVE STATISTICS name PURPOSE To print wave statistics defined PARAMETERS name Name of the wave statistics Postresp 5 129 Postresp 5 130 15 DEC 2007 PRINT WORKABILITY ANALYSIS WORKABILITY ANALYSIS namet PURPOSE To print workability analysis created PARAMETERS name Name of the workability analysis SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 131 RUN fregt ORIGINAL FREQUENCIES RUN EQUATION SOLVER dirt PURPOSE The command is used to solve the equation of motion for selected frequencies or for the original frequencies for which the matrices are given Note that the frequencies have to be given within the range of frequencies for the matrices i e Postresp will not perform extrapolations PARAMETERS EQUATION SOLVER The motion of equation will be solved dir Wave direction to be included in the solution ORIGINAL FREQUENCIES The motion of equation will be solved for all frequencies for which the matrices a
94. SHORT TERM STATISTICS RAYLEIGH EASTATE DURATION 3600 10800 1 2 3 naw wy DH 3 7 Solving Equation of Motion Solving the equation of motion will be done by the command freq RUN EQUATION SOLVER dir ORIGINAL FREQUENCIES where dir and freq are a subgroup of the original directions and specification of additional frequencies each assumed to be located between pairs of original frequencies extrapolation is not allowed for which the solution of equation of motion will be done It is not possible to specify additional directions ORIGINAL FREQUENCIES is an option for solving the equation of motion for the specified directions and all the original frequencies Running additional frequencies Postresp will interpolate the matrices for the current body if it is a SINGLE body For a MULTI body system the matrices for each of the bodies auto coupling matrices and the matrices for the interaction between bodies cross coupling matrices will be interpolated Postresp SESAM 3 8 15 DEC 2007 Program version 6 2 The following matrices are treated as independent of both frequency and direction BODY MASS AND INERTIA HYDROSTATIC RESTORING COEFFICIENTS ANCHORING RESTORING VISCOUS DAMPING The following are treated as dependent only on frequency ADDED MASS POTENTIAL DAMPING None of the matrices are treated as dependent only on direction The excitation forces and the response var iables for the mot
95. STANT GRAVITY default 0 5 because the default does not exist when the command line is interpreted This will work DEFINE CONSTANT GRAVITY default 0 5 Everything typed in programming mode will be logged as a comment If the program produces a numerical value that is used in a command the numerical value will be logged as part of the command after the pro gramming expression has been logged as a comment 4 6 4 Accessing default Values Postresp will in many cases supply a default value when input is requested The default will be presented in An example DEFINE CONSTANT GRAVITY Gravity 9 81 The default may be accepted using one of the following methods Type lt Return gt i e an empty input line to accept the current default Type colon to accept the current default The colon must be preceded by a blank space if it is not the first item on the command line However several colons may follow each other without intervening spaces Type semicolon to keep accepting defaults as long as they are presented or until the command is complete The semicolon must be preceded by a blank space if it is not the first item Postresp SESAM 4 24 15 DEC 2007 Program version 6 2 on the command line However several semicolons may follow each other without intervening spaces Please note that an empty line in a command input file will not be interpreted as a default The colon and semicolon may be written into a co
96. T BE FORE Until the status is changed rows will be keep being in serted before rowl immediately after the last row entered Wildcards may be used to specify row1 provided that one row is matched uniquely Overwrite row1 with row2 Set the default status to OVER WRITE The next row s that are entered will continue over writing until the default status is changed scrolling down as they do so When the last row has been overwritten the default status is changed to INCLUDE Wildcards may be used to spec ify row1 provided that one row is matched uniquely List the contents of the matrix Insert Exclude or overwrite using row depending on the de fault status The initial default status is INCLUDE In the case of a one dimensional vector containing numerical values or names which can be integer values row or row2 can be substituted with the interval expression GROUP from to step which expands to the values from from step from 2 step up to but not exceeding to When a default vector matrix 1s being presented or if the left parenthesis has been typed as input Postresp presents the right parenthesis as default A single question mark will show the possible alternatives in the matrix Use LIST to see the rows in the matrix Examples DEFINE RETURN PERIOD GROUP 10 50 10 will define return periods to be used in long term response calculation as 10 20 30 40 and 50 CREATE WAVE SPECTRU
97. TERS DIFFERENCE SUM ALL SECOND ORDER ONLY FIRST ORDER INCLUDE option spec sprea Use only difference frequency QTF to represent second order response Use only sum frequency QTF to represent second order re sponse Use both sum and difference frequency QTFs to represent sec ond order response Exclude first order effects from reported statistics Include the first order and mixed first and second order contri butions to the reported statistics Specifies for what the second order statistics are to be calculat ed For the time being only the excitation forces are available The options for forces are EXCITATIONFORCE 1 EXCITATIONFORCE 2 EXCITA TIONFORCE 3 EXCITATIONFORCE 4 EXCITATIONFORCE 5 EXCITA TIONFORCE 6 If first order effects are to be included the corresponding first order force is selected automatically from FORCEI FORCE2 FORCE3 FORCE4 FORCES FORCE6 Name of the wave spectrum to be used in the calculations Name of the wave spreading function to be used Must be given as NONE if short crested sea is required SESAM Postresp Program version 6 2 15 DEC 2007 5 119 dir Main wave direction prob Probabilities of exceedance for which the maximum and mini mum response levels are requested EXAMPLES PRINT SECOND ORDER STATISTICS ALL FIRST ORDER INCLUDED EXCITATIONFORCE 1 PM1 NONE 0 0 0 001 0 0001 Postresp SESAM 5 120 15 DEC 2007 Program ve
98. a line Examples DEFINE PRESENTATION OPTION ABSCISSA AXIS PERIOD change to period This is a comment SESAM Postresp Program version 6 2 15 DEC 2007 5 1 5 COMMAND DESCRIPTION The hierarchical structure of the line mode commands and numerical data is documented in this chapter by use of tables How to interpret these tables is explained below Examples are used to illustrate how the com mand structure may diverge into multiple choices and converge to a single choice In the example below command A is followed by either of the commands B and C Thereafter command D is given Legal alternatives are therefore A B D and A C D RIEN In the example below command A is followed by three selections of either of commands B and C as indi cated by 3 For example A B B B or ABB C or AC BC etc B Ale In the example below the three dots in the left most column indicate that the command sequence is a contin uation of a preceding command sequence The single asterisk indicate that B and C may be given any number of times Conclude this sequence by the command END The three dots in the right most column indicate that the command sequence is to be continued by another command sequence In the example below command A is followed by any number of repetitions of either of the sequences B D and C D Note that a pair of braces is used here merely to define a sequence that may be repeated The braces are not commands t
99. ac ing or be LOGARITHMIC with base 10 The title at the x axis can be specified by Postresp DEFAULT or overridden with a SPECIFIED text lt xtitle gt The following options are default when Postresp starts up with a new database SET SE SET SET GRAPH GRAPH l GRAPH GRAPH XAXIS ATT XAXIS ATT XAXIS ATT XAXIS ATT RIBUTES DECIMAL FORMAT GENERAL RIBUTES LIMITS FREE RIBUTES SPACING LINEAR RIBUTES TITLE DEFAULT Postresp 5 142 SESAM 15 DEC 2007 Program version 6 2 SET GRAPH YAXIS ATTRIBUTES YAXIS ATTRIBUTES LIMITS EXPONENTIAL FIXED GENERAL INTEGER FREE DECIMAL FORMAT FIXED ymin ymax LINEAR LOGARITHMIC DEFAULT SPECIFIED ytitle SPACING TITLE PURPOSE Set options controlling the attributes of the y axis in a graph PARAMETERS DECIMAL FORMAT LIMITS SPACING TITLE EXAMPLES Controls the presentation of numbers labelling the y axis The numbers can be pre sented in EXPONENTIAL format in FLXED format as INTEGERs or in GENER AL free format Controls the limits of the y axis These can either be FREE i e determined by the data that are being presented or FIXED to the min value lt ymin gt and the max val ue lt ymax gt Controls the spacing of numbers along the axis The axis can have a LINEAR spac ing or be LOGARITHMIC with base 10 The tit
100. after this will be excluded from the selection until the status is changed text Include or exclude the items matching text depending on the default status The initial default status is INCLUDE In the case of a selection of numerical values or of a selection between names which can be integer val ues the text can be substituted with the interval expression Postresp SESAM 4 26 15 DEC 2007 Program version 6 2 GROUP from to step which expands to the values from from step from 2 step up to but not exceeding to When a default selection is being presented or if the left parenthesis has been typed as input Postresp presents the right parenthesis as default A single question mark will show all items in the list listing the selected items in parenthesis Prefixing the question mark with a text text will show all items in the list matching text Examples PRINT RESPONSE VARIABLE will print all response variables PRINT RESPONSE VARIABLE EXCLUDE SECL will print all response variables except sectional loads named SECLnn 4 6 9 Entering a Vector or Matrix of Values The syntax for entering a vector or matrix of values is an extension of the syntax for selecting values from a list In this case there is no fixed list to select from Instead the items are inserted and manipulated as the vector matrix is entered The term vector is used for the case where the input is one dimensional An exa
101. alues of the two response components tend to be both large or small at the same time whereas if p is large and negative 1 e approaching 1 the value of one response component tends to be large when the other is small If p is small or zero there tends to be little or no relationship between the two response components B4 4 Response Maxima The distribution of response maxima in a short term seastate is described using the Rice distribution func tion s 2 F x o gt E LS Ox x B 77 where is the normal probability integral o is the standard deviation of the response and e is the spec tral width parameter given by 1 Mo P 2 M A B 78 In the case of 0 the general Rice distribution reduces to the Rayleigh distribution Feo 20 B 79 SESAM Postresp Program version 6 2 15 DEC 2007 B 19 The most probable largest response Xmax occurring within a time interval of N response maxima is approx imately given by X max J20 ln V I EN JJ B 80 In the case of a narrow banded spectrum i e 0 the most probable largest response is given by Xnax 7 420 AN B 81 where N represents the number of zero upcrossings in the short term sea state Under narrow band condi tions the number of zero upcrossings N equals the number of response maxima N The number of zero upcrossings N may be determined from the duration of the short term seastate D and the mean zero upcrossing respons
102. ame of the curve Postresp 5 99 Postresp 5 100 15 DEC 2007 DISPLAY WAVE SPECTRUM WAVE SPECTRUM name PURPOSE To display wave spectra created by the user PARAMETERS name Name of the spectrum SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 101 DISPLAY WAVE SPREADING FUNCTION WAVE SPREADING FUNCTION name space PURPOSE To display energy spreading for elementary wave directions created by the user PARAMETERS name User given name of the function space User input space between each wave direction angle for which the energy spreading function will be displayed This space is independent of what the program will use in calculating the response spectra Only asked for if the name of the function corresponds to a cosine power function Postresp SESAM 5 102 15 DEC 2007 Program version 6 2 FILE EXIT FILE PLOT READ PURPOSE This command is used for file handling control or to terminate the program execution SESAM Postresp Program version 6 2 15 DEC 2007 5 103 FILE EXIT EXIT PURPOSE To exit from Postresp The termination of Postresp is also available as the main command EXIT in line mode Note that EXIT can not be abbreviated Postresp SESAM 5 104 15 DEC 2007 Program version 6 2 FILE PLOT PLOT PURPOSE Plot last display on hard copy devic
103. an drift forces HDRFTI horizontal force in x direction HDRFT2 horizontal force in y direction SESAM Postresp Program version 6 2 15 DEC 2007 3 11 HDRFT6 horizontal moment about z axis SECL amp amp amp Sectional loads forces and moments amp amp amp is the section number and the degree of freedom SECL amp amp amp 1 force in x direction SECL amp amp amp 2 force in y direction SECL amp amp amp 3 force in z direction SECL amp amp amp 4 moment about x axis SECL amp amp amp 5 moment about y axis SECL amp amp amp 6 moment about z axis PS amp P Panel pressure alt 1 for panel indexes less than 1000 amp is the section or symmetry plane number and the internal panel index or pressure point number P amp P Panel pressure alt 2 for panel indexes larger than 999 amp is the section or symmetry plane number and the internal panel index GRES General response number This response is stored on the Results Interface File with dimension so this could be any kind of transfer function The descriptive text connected to a response variable may give a full description of the origin of the response For instance for stresses forces or displacements taken from a Sesam results interface file ELEV sea surface elevation in point number PRES pressure calculated in point number PVEL amp amp amp particle velocity in point nu
104. and Section 4 6 All relevant dialogue boxes are shown in Appendix C 4 1 Program Environment Postresp is available in the following hardware environments Unix computers of various vendors Windows 2000 NT and XP often referred to as PC Postresp may be run in three different modes In interactive graphics mode with menus and dialogue boxes where input may be given using a mouse as well as the keyboard Graphics mode usage also gives access to the line mode facilities In interactive line mode Unix only using only character based input In batch mode which uses the line mode syntax and facilities How to start the program in the different modes is described below Postresp SESAM 4 2 15 DEC 2007 Program version 6 2 4 2 Starting Postresp Start Postresp in graphics mode from the Sesam Manager by one of the commands Result Response POSTRESP Utility Run POSTRESP If running from the operating system command prompt window simply type the program name to start the program prompt gt postresp Postresp responds by opening the main window and overlaying it with a dialogue box requesting the data base file prefix name and status Note that the default status is Old even when Postresp suggests a new database file Type in the file prefix and name and select the proper status then press the OK button or type lt Return gt Pressing the Cancel button will abort the session If the file specification i
105. avity and o is the frequency corresponding to the peak of the spectrum o 27 T A more convenient form of the Pierson Moskowitz spectrum has been developed in terms of the seastate parameters H and T and is referred to as the Modified Pierson Moskowitz spectrum This form is of more direct use for engineering purposes and may be written as ToT SES so EO AG 87 27 B 6 The significant wave height H is determined from the zero order moment mg of the wave spectrum H 4 m B 7 The mean zero up crossing period is determined from the zero order moment m and the second order moment m of the wave spectrum T 2n jmg m B 8 B1 3 JONSWAP Spectrum The Jonswap spectrum can be described as a function of the four parameters a O Y 6 or alternatively by the four parameters H T y In the first form the spectrum can be written as S Q Op Y o ag o ep nes Ay B 9 where a F y B 10 P We now want to establish a relation between 0 0 and H T We do this by computing my and my From the spectrum definition above we see that the moments can be written as 2 4 mg ag o Foy o B 11 Postresp B 4 15 DEC 2007 m ago Faly 0 Now we can easily compute Hs and T z as H a o 4 mo 4go Ja Fo y 6 T a 0 27 mg m 270 Fo Fr T Fo FP and the inverse relations as Fo Hn a H T pA pA 2 1 1 o s T 2noT Fy F B 1 4 Gamma Spectru
106. be up to 12 characters long and may contain any alphanumeric character as well as the under score _ and the hyphen A name must begin with an alphanumeric character The input case of a name is preserved but it is not of significance when comparing names at a later stage e g the name Span is considered to be identical to the name span Text must be protected in single quotes if it contains blank space s and or special characters SESAM Postresp Program version 6 2 15 DEC 2007 4 25 4 6 7 Selecting a single Alternative from a List In many cases Postresp will require a selection of a single alternative from a list An example is at the main prompt where the main commands are presented for selection The selection needs not be between com mands it could also be between named objects or between numerical values In selection of a single value abbreviation is allowed see Section 4 6 5 but wildcards cannot be used An exact match is always preferred Thus it is possible to select an item that is an abbreviation of another item in the list by typing the item exactly A single question mark will show all items in the list Prefixing the question mark with a a text text will show all items in the list matching text The input text may be typed in upper or lower case as desired Postresp disregards the case of the text when it does the comparison The input text used to make the selection is not logged on the journal
107. be used to get information Type symbol to get the syntax of a function or procedure or to see the value of a variable or a predefined constant symbol is the name of the function procedure variable or constant SESAM Postresp Program version 6 2 15 DEC 2007 4 21 Type expression to see the value of expression a calculated numerical expression Note that it is necessary to type the question mark before the expression in order to see the value otherwise the value is just passed on to the current command The keyword show may be used in programming mode instead of the question mark with the same effect 4 6 2 Command Input Files Line mode commands may be read from a file as well as typed directly into Postresp Such a file may con tain any syntax that is allowed in line mode including reading another command input file To read in a command input file type an followed by the filename To read parts of the file specify the number of lines to read after the filename If the filename does not have an extension i e a dot and the fol lowing part Postresp adds jnl to the name Postresp may have more than one command input file open at one time It will always read the files sequen tially finishing the last opened file first To get a list of the currently open files type The last opened command input file may be closed explicitly by typing the followed by two dots When a command input file is being read the
108. box SESAM Program version 6 2 The graphics mode input of this is quite flexible The values are presented in columns in a scrollable box Under the box is one input field for each column in the matrix one field if it is a vector Under the input field s are two rows of buttons that are used to manipulate the contents of the box Type values into the input fields and hit Return in the last bottom field The values are then inserted at the bottom or before the selected row or will over write the selected row depending on the default status The initial status is Include which inserts values at the bottom The input fields are cleared after the inser tion is complete Instead of pressing Return a button may be pressed The effect of this is Include Exclude Overwrite Insert before Include the values in the input field s at the bottom then clear the input fields Set the default status to Include Exclude all selected rows from the matrix vector The selection process is identical to the se lection described in Section 4 5 5 Set the default status to Include Overwrite the selected row with the contents ofthe input fields Only one row can be selected in the scrollable box The next row if any will then be selected and the default status will be set to Overwrite The input fields will be cleared Insert the contents of the input fields before the selected row Only one row can be selected in the scrol
109. c Lower sequence number on the sectional forces This requires a sequence numbering from the Global Response Interface File usec Upper sequence number on the sectional forces SESAM Postresp Program version 6 2 15 DEC 2007 5 89 DISPLAY MATRIX ADDED MASS MATRIX POTENTIAL DAMPING body elem TOTAL DAMPING PURPOSE To display the frequency dependent matrices element in a 6x6 matrix PARAMETERS ADDED MASS POTENTIAL DAMPING TOTAL DAMPING body elem added mass potential damping or total damping for a selected Added mass matrix Potential damping matrix Total damping matrix Optional body identification if a multiple body solution is exe cuted or several single body solutions exist Both the body ma trix and the coupling matrices will be available Only available if DEFINE PRESENTATION OPTION SIMULTANE OUS BODIES is set to ALL Element number in the matrix The number must be specified as 2 digits giving the row and column number in a 6x6 matrix For instance the heave heave element will be referred as 33 in the current body Postresp SESAM 5 90 15 DEC 2007 Program version 6 2 DISPLAY REFRESH REFRESH PURPOSE To refresh the display on screen The previous commands and selection are used in the refreshing The user may change some presentation options like the x axis required colour setting grid on off etc The DIS PLAY REFRESH command
110. cies SESAM Postresp Program version 6 2 15 DEC 2007 3 3 a Standard motion combinations are rigid body combinations in a given specific point on the structure The motions may be displacements or derived values i e velocities or accelerations and they are available for the three translation components Some or all of the six degrees of freedom may be included and each component contributing is added together with a multiplied weight arm Figure 3 1 shows a standard abso lute combination where the motion in the z direction is wanted in point SP Figure 3 1 Standard absolute combination in point SP The equation used is TRSP TRCygayg t y TRCrorr X TRCprrcu 3 1 where TRSP the resulting transfer function in point SP TRC the transfer functions at the origin of the global coordinate system in the free surface SWL X the local x coordinate y the local y coordinate The command for the standard motion combination given above is CREATE RESPONSE VARIABLE ADISZSP Abs displacement in SP COMBINED MOTION SP DISPLACEMENT ABSOLUTE Z b Force combinations are mainly appointed to offer the user an option to combine sectional force compo nents to obtain resulting forces in a specified point in a section of the structure This is very often used in connection with ship analysis Each component is added together with a scaling factor The user may add as many components as wanted By this the
111. city exceeds this val ue when the vessel re enters the water The value is given as the Froude number gL v velocity g gravity L characteristic length EXAMPLES CHANGE LONG TERM RESPONSE RESPONSE VARIABLE ONLY PITCH ROLL ONLY 0 0 22 5 45 0 67 5 90 0 135 0 180 0 CHANGE LONG TERM RESPONSE RESPONSE VARIABLE ROLL 90 0 CHANGE LONG TERM RESPONSE SLAMMING FKPT1 1 0 0 15 90 0 CHANGE LONG TERM RESPONSE SLAMMING FKPT1 1 0 0 15 ONLY 0 0 22 5 45 0 67 5 90 0 Postresp SESAM 5 16 15 DEC 2007 Program version 6 2 CHANGE MATRIX RESTORING MATRIX elem val BODY MATRIX PURPOSE To change the contents of a global matrix PARAMETERS RESTORING Frequency independent hydrostatic restoring matrix BODY MATRIX Frequency independent inertia coefficient matrix elem Element number in the matrix The number must be specified as 2 digits separated by a dot giving the row and column number in a 6x6 matrix e g 11 or 34 val Matrix value EXAMPLES CHANGE MATRIX RESTORING 33 5 11237e 006 El P P CHANGE MATRIX BODY MATRIX 11 2 41367e 007 SESAM Postresp Program version 6 2 15 DEC 2007 5 17 CHANGE RESPONSE VARIABLE name txt dir freq real imag MIRROR respt RESPONSE VARIABLE PURPOSE To change the contents of a response variable PARAMETERS name Name of the response variable txt Descriptive
112. created Overview of the response spectra created Overview of the response variables created Overview of the short term responses created Overview of the specific points created Overview of the wave spectra created Overview of the wave energy spreading functions created Postresp SESAM 5 114 15 DEC 2007 Program version 6 2 WAVE STATISTICS Overview of the wave statistics models created WORKABILITY ANALYSIS Overview of the workability analysis created SESAM Postresp Program version 6 2 15 DEC 2007 5 115 PRINT RESPONSE CO SPECTRUM numbert DUMP SPECTRUM number RESPONSE CO SPECTRUM PURPOSE To print calculated response cross spectra Only the spectrum characteristics such as the spectrum period and moments will be printed unless the user asks for a dump The dump is not available for a response spectrum calculated with a general gamma spectrum PARAMETERS number Reference number of the response cross spectrum DUMP SPECTRUM A response spectrum for given reference number will be dumped i e spectrum or dinates for 201 frequencies will be printed Postresp SESAM 5 116 15 DEC 2007 Program version 6 2 PRINT RESPONSE SPECTRUM number DUMP SPECTRUM number RESPONSE SPECTRUM PURPOSE To print calculated auto response spectra Only the spectrum characteristics such as the spectrum period and moments will be printed unless the user asks for a dump
113. d except for one case If it is used after an inserted command has been completed The reason is that the completion of the inserted command causes the first part of the command to be logged before the inserted command It is therefore necessary to log the double dot in this case so that the log file will have a correct syntax To abort parts of a command going back to the last LOOP or to the point of a left parenthesis in a multiple selection or a vector or a matrix type lt lt lt CtrIC may also be used to abort a command hold the Control key while typing C Usage of CtrlC will throw away all of the input of the command line as well as abort the command Unlike the double dot the input before the CtrlC is not processed CtrIC may also be used to abort a running analysis 4 6 13 Access to the Operating system It is possible to issue a command to the operating system at any point in a Postresp command not from pro gramming mode This is done by typing an exclamation mark followed by the operating system com mand Everything on the input line after the exclamation mark is sent to the operating system This example taking from a run on a VAX computer will list all files matching postresp Idir postresp This facility is very useful for obtaining directory listings editing files eg input files spawning into the operating system to do more complicated tasks etc This facility is also available from the command in
114. d order output can be individually included or excluded from the calculation It should be noted that when first order effects are included the reported moments and extremes will account for the interaction of first and second order effects This type of model and analysis have been applied for example to study the high frequency springing response of tension leg platforms Similarly the slow drift analysis of moored vessels has been conducted using the difference frequency part of the Volterra model SESAM Postresp Program version 6 2 15 DEC 2007 2 11 2 12 SN curves This is used to define the fatigue characteristics of a material subjected to repeated cycle of stress of con stant magnitude The SN curve delivers the number of cycles required to produce failure for a given magni tude of stress The SN curve may be calculated by the program or it may be user defined The program generates the following SN curves Name m S LogN LogA API X 4 380 3 500E 07 18 301 41 344 API XP 3 740 2 300E 07 8 301 35 834 DNV X 4 100 3 400E 07 18 301 39 180 DNVC I 3 000 7 644E 07 17 000 30 650 DNVC Ib 3 000 8 318E 07 17 000 30 650 DNVC II 3 000 6 213E 07 7 000 30 380 DNVC III 13 000 9 190E 07 17 000 30 890 DNVC IIIb 3 000 1 000E 08 7 000 31 000 DNVC IV 3 000 7 470E 07 17 000 30 620 NS B SEA 14 000 4 744E 07 8 301 39 006 INS C SEA 3 500 3 322E 07 18 301 34 626 NS D SEA 3 000 1 966E 07 18 301 30 182
115. dan gang rei tikker bekk edge tees 2 10 SNECUIVES EIER 2 11 Stochastic Fatigue Calculations eese estet enne thea te nenne tatnen e ron tns na 2 12 USER S GUIDE TO POSTRES P vesccssscescsaxcscciacsescsccenpssctaacscauceccens0scsasesecdecsesaccoesoswsecadsess 3 1 Short Introduction to how to use Postresp cccccesseesseeseestecetecesceeeeeeeecaecseseeeseeeeseeessececeeeeeeeeesees 3 1 Generation of Combined Responses enne nennen nennen eren enn 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 3 10 3 11 4 1 4 2 4 3 4 4 4 5 4 6 Calculation of Response Spectra 2 ener cte n e n e vet er en enel ro 3 4 Calculation of Short Term Response sse ener entrer eterne nnne 3 5 Calculation of Long Term Responses sse eene ener nennen enne innen enne nn 3 6 Calculation of Short Term Statistics ssooneronorrnrnvrnnenrrernrrnrnnrnnennrersennennnsneeneensernnrnnenesnrenssersensensenne 3 7 Solving Equation of M tiOh sennoina eene nnne en tenente enr enne enne enne 3 7 Workability Analysis 5 so RR RU da tie ee E V BENE 3 8 Calculation of Second Order Statistics sse entente rentrer nennen 3 9 Calculation of Stochastic Fatigue sss enne enne nennen nen 3 9 Internal Name COnvehtlOns za tine t Ctt ears nente tege e te ette ueste eer tota 3 10 EXECUTION OF POSTRESP a ioscss ees ck treetan eoo ve Vau Cor eERe naue RE ER So PNE so ena a Ya RE CP PEN LES 4 1 Program Enyiuonment 5nd
116. dy point WAVE DIRECTION prob SECTIONAL FORCE DIAGRAM body dof prob dir Isec usec PURPOSE To display long term response for a selected response variable long term slamming in a specific point or a sectional force diagram as a function of the section numbers PARAMETERS RESPONSE VARIABLE SLAMMING SECTIONAL FORCE DIAGRAM body resp point dir LOG Q WAVE DIRECTION prob Long term response for a selected response variable is dis played Long term slamming is displayed A long term sectional force diagram will be displayed as force moments against the section number For a ship vessel this will give the long term moment diagram over the ship length Optional body identification Only if the presentation option is specified as several bodies in the same plot Only available if DEFINE PRESENTATION OPTION SIMULTANEOUS BODIES is set to ALL Response variable for which the long term response is to be dis played Specific point where long term slamming is calculated Wave direction The abscissa axis will be the logarithm of the probability level used in the calculation The abscissa axis will be the wave directions used in the calcu lation Probability level for which the long term response has been cal culated Postresp SESAM 5 88 15 DEC 2007 Program version 6 2 dof Degree of freedom for which the sectional force diagram will be displayed Ise
117. e This command is also available as the main command PLOT in line mode SESAM Program version 6 2 FILE READ Postresp 15 DEC 2007 5 105 SIF FORMATTED READ SIN NORSAM prefix name SIU UNFORMATTED VVAMIT RESULTS PURPOSE This command is used in the frequency domain part It opens and reads the Hydrodynamic Results Interface File G file containing a single or multiple body solution or a set of WAMIT results files When complete the opened files will be closed The command may also be used to read external scatter diagrams from a file on Hydrodynamic Results Interface File format The scatter diagrams can be directional or wave direction independent PARAMETERS SIF FORMATTED SIN NORSAM SIU UNFORMATTED VVAMIT RESULTS prefix name Hydrodynamic Results Interface File on formatted ASCII format Hydrodynamic Results Interface File on direct access format Hydrodynamic Results Interface File on unformatted sequential format A standard set of VVAMIT results files can be read All files vvill have the same name but different suffix corresponding to the VAMIT definitions Postresp requires that the file containing the excitation forces lt name gt 2 or lt name gt 3 is present In addition the gravity and characteristic length should be fetched from the lt name gt GDF file Do also remember to define the water density if it is not 1025 as the default in Pos tresp
118. e period T i e NF B 82 When viewed within extreme value statistics the most probable largest value has a 63 chance of being exceeded i e out of a large number of identical floating structures present in the same ocean area 63 will experience a higher maximum value than the most probable largest B5 LONG TERM RESPONSE In Postresp the long term marginal distribution of response is derived using the short term Rayleigh distri butions F x H I of response maxima the short term mean zero up crossing period of the response T H T and the joint probability density of the wave parameters AH T Ref 2 The joint probability density may be based on a statistical model of wave data or taken directly from a wave scatter diagram However in connection with extreme response prediction the use of a statistical model is preferred since it provides a means of including the steep infrequent seastates that may in some cases be absent from a wave scatter diagram based on observations of limited duration B5 1 Derivation of Long Term Distribution It is required to determine the long term marginal distribution F x for response variable x The total dura tion to be considered is denoted Dz The infinitesimal duration of any sea state may be expressed by D GI T D fUT T dH dT B 83 The expected number of response maxima in the sea state is given by the duration of the sea state divided by the mean response period
119. ead in global matrices and first order excitation forces FATG used to perform fatigue analysis in the frequency domain 2ORD used to operate on second order sum and difference results TIME used to perform statistical postprocessing on any time series stored on the Results Interface File Note The extension TIME is available as a separate executable named Postresp_TIME Table 1 1 gives an overview of the different features that are applicable to the extensions The commands applicable to the extension TIME are given in a separate user manual Table 1 1 EXTENSION CHARTER SOLVER FATUR ANALYSIS S ORDER 2 9 Equation of Motion X 2 11 Second Order Statistics X 2 12 SN curves x 2 13 Stochastic Fatigue Calculations x 3 9 Solving Equation of Motion X 311 Calculation of Second Order Statistics 5 COMMAND DESCRIPTION X X x SESAM Postresp Program version 6 2 15 DEC 2007 2 1 2 FEATURES OF POSTRESP 2 1 Response Variables The transfer functions are called response variables in Postresp They are addressed by a character name consisting of up to eight letters The user may allocate any name to new response variables generated by the CREATE command except those already defined by the internal name convention ref Chapter 3 The transfer functions are usually read from a Results Interface File but they may also be typed in directly The transfer functions may be combined either a
120. effects B7 Frequency Domain Fatigue B 7 1 Basic Assumption There are two basic assumptions First stress cycles are assumed to occur with mean rate vo and an arbi trary stress range S is assumed to have Weibull distribution with scale parameter a and shape parameter b F x P S lt x 1 exp 2 B 134 This can include both linear as well as linear response provided appropriate choices of a and b are made based on the non linearity ref Winterstein Ref 10 Secondly we assume a single slope S N curve N S KS B 135 or for a bilinear SN curve NOSES SSS se NGS RS SG B 136 In this case the user inputs m as well as m and K The parameter K is given by m m K KS B 137 to ensure continuity between the two curves B 7 2 Basic results The basic result calculated by Postresp is the damage rate DR per unit time This is given by Vo Vo DR K m a b Vo ES aa eae a B 138 K E S x r 1 m b in which I is the standard Gamma function The corresponding total damage in period 7 is Dor T4 DR K m a b vo B 139 The parameters K m and 7 should be input by the user of the fatigue analysis while the parameters a b and vg is calculated internally by Postresp This is described in the following chapters for the various cases of interest For the bilinear SN curve the damage rate in Equation B 138 is replaced by SESAM Postresp Program version 6 2 15 DEC 2007 B 29 SNO of xe
121. en in Appendix A The HELP command is not described here It is intended purely to serve as on line help Usage of the HELP command is not logged When in doubt how to do things try the HELP command or take a look at Section 4 5 2 and Section 4 6 1 5 1 Commands for Postresp The following chapter shows the syntax for the line mode commands in the frequency domain The com mands specific for the time domain are described in a separate user manual The description of the com mands is naturally valid for the commands in the graphic mode as well 5 2 Frequency domain ASSIGN ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION ASSIGN WAVE DIRECTION PROBABILITY ASSIGN WAVE SPECTRUM SHAPE ASSIGN WAVE SPREADING FUNCTION ASSIGN WAVE STATISTICS CHANGE CHANGE LONG TERM FATIGUE CHANGE LONG TERM RESPONSE CHANGE MATRIX CHANGE RESPONSE VARIABLE CHANGE SN CURVE CHANGE SPECIFIC POINT CHANGE WAVE SPECTRUM CHANGE WAVE SPREADING FUNCTION CHANGE WAVE SPREADING FUNCTION COSINE POWER CHANGE WAVE SPREADING FUNCTION USER SPECIFIED SESAM a WAVE S PREADIN UNCTION GE WAVE SPREADING FUNCTION COSINE POWER
122. ency EXAMPLES CREATE WAVE SPECTRUM User2d 2D USER SPECIFIED ONLY 0 1 1 0 1 0 2 45 1 3 45 1 4 SESAM Postresp Program version 6 2 15 DEC 2007 5 45 CREATE WAVE SPECTRUM GENERAL GAMMA WAVE SPECTRUM name txt GENERAL GAMMA FULL RANGE tzmin tzmax incr Isp nsp SCATTER DIAGRAM Isp nsp SINGLE hs tz Isp nsp PURPOSE To create a single or full range set of wave spectra based on a general gamma spectrum type If the option FULL RANGE is used the first 4 letters of the name will be used as prefix for the automatic name genera tion Note that a general gamma spectrum cannot be displayed or plotted PARAMETERS name Name of the spectrum or prefix of the full range generated spectra txt Descriptive text of the spectrum If FULL RANGE the 20 first letters will be used in addition to the internal text generation e g Tz 10 0 FULL RANGE Full range calculation of general gamma spectra I e wave spectra with Hs equal to 1 0 and different Tz values given as a range will be generated This alternative will create internal names which will be prfx where prfx is the first 4 letters of the name given and is an integer number in increasing order see Section 3 3 lsp l parameter in the general gamma spectrum nsp n parameter in the general gamma spectrum tzmin Minimum value of Tz for full range calculation tzmax Maximum value of Tz for full ra
123. ere C is a constant factor for each response variable x involved in the combination of the transfer func tions H B4 SHORT TERM RESPONSE The responses of a structure to an irregular short crested stationary seastate may be calculated from a wave energy spectrum and the transfer functions of the various responses by means of the linear superposition technique B4 1 Spectral Moments The c order spectral moment M is given by SESAM Postresp Program version 6 2 15 DEC 2007 B 17 m 2 o 2 MS f f o H 0 2 S f a doda B 69 n 2 0 The significant response X double amplitude for the response variable x is defined as the mean of the one third largest responses in the response spectrum This is related to the zero moment Mq by X 4 M B 70 The mean zero up crossing period T of the response is related to the zero order and the second order moments of the response spectrum and is given by T 2n M M B 71 B 4 2 Response Variance The variance o of the response due to short crested waves is given by 2 T 2 qo 2 o B f A o S fla doda M B 72 m 2 0 where B is the heading angle between the direction of the main wave system and the ship B a is the heading angle between the elementary sinusoidal waves and the ship and o is the angle of the elementary waves relative to the main direction of the irregular wave system See Figure B 1 The individual response spectra are defined by Sp o
124. estion mark may be used to examine any one of these The predefined constants include PI and E The list of functions is extensive Examples of programming mode usage CREATE SPECIFIC POINT SP1 text 10 0 20 3 0 log log x natural logarithm x log 10 y 2 x sin 0 44 mi exp x 1 54 show y y 0 9968869507 is a variable normaldist SESAM Postresp Program version 6 2 15 DEC 2007 4 23 normaldist x mean stdv Distribution function for Normal distribution show normaldist 2 0 1 0 977249938 There are two special cases that deserve attention Do not use a variable immediately after it is assigned This will not work x exp 3 2 y x 2 The reason is that Postresp interprets the complete programming expression before the value is assigned to x thus x has no value when it is being used The solution is to either insert two dollars between the assignment and the usage leaving and entering programming mode or go to a new input line after the assignment e Postresp puts any default numerical value into a variable called default so that it may be modified and reused However when using this value the usage of the value must be the first item on the input line The reason for this is that Postresp interprets the complete input line when it is read and the default var iable is not assigned its value until at the point where the default is becoming active This will not work DEFINE CON
125. etailed description of the available input commands Appendix A contains input and output for tutorial examples Appendix B includes additional theory description for Postresp Appendix C includes pulldown menus and dialogue windows Additional literature is listed in the References part 1 4 Status List There exists for Postresp as for all other Sesam programs a Status List providing additional information This may be Reasons for update new version e New features Errors found and corrected Fte Use the program Status for looking up information in the Status List In Manager click 2 Then give File Read Status List and select Postresp In the Status List Browser window narrow the number of entries listed Entries relevant to a specific version only Entries of a specific type e g Reasons for Update Entries containing a given text string Click the appropriate entry and read the information in a Print window To look up information in the most updated version of the Status List go to our website www dnvsoft ware com click the Support shortcut and then the Sesam Status Lists link and log into this service Contact us for log in information Postresp SESAM 1 4 15 DEC 2007 Program version 6 2 1 5 Postresp extensions There are four extensions to Postresp denoted Ext EQUA FATG 2ORD and TIME EQUA used to solve the equation of motion for user specified vvave frequencies given that Postresp has r
126. fferent sea states SESAM Postresp Program version 6 2 15 DEC 2007 5 57 CREATE WAVE STATISTICS ISSC SCATTER DIAGRAM WAVE STATISTICS name txt ISSC SCATTER DIAGRAM PROBABILITY hs tl prob OCCURENCE hs tl occ PURPOSE To create wave statistics model for use in the long term response calculation The current wave statistics model describes the sea state conditions during a long term period and consists of T1 and Hs values and their probability of occurrence By this command the wave statistics model is given through a ISSC scatter diagram PARAMETERS name Name of the wave statistics txt Descriptive text for the model PROBABILITY Each sea state i e cell in the diagram will be given a probability of occurrence OCCURENCE Each sea state i e cell in the diagram will be given as number occurrences during the long term period hs Significant wave height Hs tl Mean period T1 prob Probability for given zero upcrossing period T 1 and significant wave height Hs occ Occurrence of the seastate given the zero upcrossing period T1 and significant wave height Hs EXAMPLES CREATE WAVE STATISTICS WISSC ISSC Scatter diagram for SESAM field ISSC SCATTER DIAGRAM PROBABILITY 3 50 6 0 0 1 6 3 Ta 5 8 1 Oo 00 6 6 53 ou oO 0 0 0 Postresp SESAM 5 58 15 DEC 2007 Program version 6 2 CREATE WAVE STATISTICS NORDENSTROM
127. fied by Postresp DEFAULT or overridden with a SPECIFIED text lt ztitle gt The following options are default when Postresp starts up with a new database SET SE SET SET GRAPH GRAPH l GRAPH GRAPH ZAXIS ATT ZAXIS ATT ZAXIS ATT ZAXIS ATT RIBUTES DECIMAL FORMAT GENERAL RIBUTES LIMITS FREE RIBUTES SPACING LINEAR RIBUTES TITLE DEFAULT Postresp SESAM 5 144 15 DEC 2007 Program version 6 2 SET PLOT ON COLOUR OFF FILE prefix name FORMAT PLOT Al A2 PAGE SIZE A3 A4 AS PURPOSE Set options that affect the writing of plot to file PARAMETERS COLOUR Turn colour on off in the plot Note that display and plot colour options may be dif ferent FILE prefix name Set the plot file name and prefix The total file name is the concatenation of lt pre fix gt and lt name gt and an extension determined by the plot format FORMAT format Set the plot format PAGE SIZE Set the size of the plot EXAMPLES The following options are default when Postresp starts up with a new database SET PLOT COLOUR ON SET PLOT FILE the prefix and name of the database and journal file are defaults SET PLOT FORMAT SESAM NEUTRAL SET PLOT PAGE SIZE A4 E E Lr El Fl b 3 3 SESAM Postresp Program version 6 2 15 DEC 2007 5 145 SET PLOT FORMAT SESAM NEUTRAL POSTSCRIPT HPGL 7550 W
128. finitions for the components of the I matrix D and S Postresp SESAM B 24 15 DEC 2007 Program version 6 2 Dy Zo 6H oj o Sy Too Hy Op 0 B 103 The standardized vector z is now composed of independent standard normal process such that the covari ance matrix IS H 2 Elz I B 104 However calculation of the statistics of x gt f based on z t is still complicated by the non zero off diagonal elements in the I matrix The solution is to factor I into a product of rotation matrices and a diagonal matrix via an eigenvalue analysis A conventional eigenvalue analysis of the Hermitian I matrix provides the eigenvalues Aj and the eigenvectors dj ro Ab 3 j 1 2N B 105 The eigenvectors are normalized to have unit length 2 H loi 7 6 6 71 B 106 The eigenvectors can also be scaled rotated such that the top half is the conjugate of the bottom half pro viding symmetry similar to that observed in the z vector 1 e 9j N 1 j B 107 On SN j The I matrix can then be decomposed into H r GAQ B 108 using the 2N x 2N matrix of eigenvectors and the diagonal matrix of eigenvalues A Substituting Equation B 108 into Equation B 102 leads to x t z oAo z u Au B 109 This equation implies the definition of u H u Qz B 110 Due to the normalization and rotation of discussed above u is now a vector of real standard Gaussian processes in time This allows the writing of Equation B 109
129. for wanted transfer functions and a given T range The short term response is given as a function of the T values used Example for HEAVE PITCH 3 wave directions Pierson Moskowitz spectra with sequence number through 21 and short crested sea CREATE SHORT TERM RESPONSE HEAVE PITCH 0 45 90 FRPM 1 21 COS2 g Use the PRINT or DISPLAY commands to examine the response spectra and the short term responses generated Examples N CO DISPLAY RESPONSE SPECTRU 1 DISPLAY SHORT TERM RESPONSE PRINT RESPONSE SPECTRUM PRINT SHORT TERM RESPONSE RN wr h If short term extreme statistics are required this is available through the PRINT command The statistics operates on generated response spectra An example working against the response spectra generated on HEAVE and PITCH and with a Rayleigh distribution and short term sea state duration as input PRINT SHORT TERM STATISTICS RAYLEIGH SEASTATE DURATION 3600 10800 1 2 3 4 5 6 3 2 Generation of Combined Responses Combined responses may be either standard combinations of motions as absolute motions or relative to the sea surface elevation or special force combinations where the user in principal is free to combine any transfer functions not only forces The only requirement to the transfer functions in a combination is that they must contain the same wave directions and angular frequen
130. four times the square root of the zero moment PARAMETERS resp Name of the response variable for which the short term response is to be calculated Wild card specification is available dir Main wave direction Wild card specification is available prfx Prefix of the full range wave spectra to be used mins Minimum sequence number of the full range wave spectra to be used maxs Maximum sequence number of the full range wave spectra to be used sprea Name of the wave spreading function to be used in the calculation when short crested sea NONE Long crested sea no wave spreading function EXAMPLES CREATE SHORT TERM RESPONSE ONLY AG2 SUB2 FY ONLY 90 0 PM 1 21 NONE Postresp 5 40 CREATE SN CURVE 15 DEC 2007 SN CURVE name txt m0 s0 logNO DEFAULT TAIL ALIGNED WITH FIRST HORISONTAL TAIL ALIGNED WITH SECOND ARBITRARY TAIL ml HORISONTAL TAIL logN1 ARBITRARY TAIL logN1 m2 PURPOSE To create an SN curve with up to 3 segments PARAMETERS name USER txt m0 m0 log NO DEFAULT TAIL ALIGNED WITH FIRST HORISONTAL TAIL ARBITRARY TAIL ml ALIGNED WITH SECOND HORISONTAL TAIL logN1 m2 Name of the SN curve Only user defined option available Descriptive text of the SN curve Slope of first segment Stress level at end first segment Log cycles to failure at end first
131. g of time series in the time domain The transfer functions in the frequency domain part are usually generated by one of the hydrodynamic programs in the Sesam suite but they may as well be transfer functions for any kind of response Postresp is a part of the Sesam program suite but can also be used to postprocess frequency dependent results from other external programs writing their results on a standard Sesam Results Interface File Postresp may in the frequency domain be used as a stand alone program without reading a Hydrodynamic Results Interface File The user may enter transfer functions interactively or by running an edited command input file Using Postresp in time domain time series are also read from the Results Interface File The Results Inter face File may be generated by Sestra or any other analysis program with the ability to create time series and geometry records on a standard Sesam Results Interface File Note Postresp for the extension TIME is delivered as a separate executable program and is docu mented in a separate user manual Postresp 1 2 15 DEC 2007 1 2 Postresp in the Sesam System Brix Explorer Sesam Config PREPROCESSING ASSOCIATED Prefem general structures Presel super element assembly Submod sub modelling Proban probabilistic risk and sensitivity INTEGRATED PROGRAM PACKAGES Wadam wave loads on general structures Waveship wave loads on ships I
132. ght for each wave period fe m KH ye Se B 56 where f H is the probability that the significant wave height does not exceed H The parameters Hy Ho Hy and m describe the threshold scale and slope of the distribution respectively B2 3 Transformation Parameters The given Weibull distribution function is written in a form suitable for direct application to instrumental data However much of the data available is based on visual observations of wave height H and wave period 7 Relationships have been developed Ref 1 to transform the visual data to equivalent instrumen tal values The relationship between wave heights is given in form Postresp SESAM B 14 15 DEC 2007 Program version 6 2 H ApH B 57 This relationship has been determined such that the probability to exceed H equals the probability to exceed H Recommended values of the transformation parameters for wave heights are Ay 1 68 and By 0 75 Similarly the relationship for wave periods is given in the form Br T ArT B 58 Recommended values of the transformation parameters for wave periods are A7 2 83 and Br 0 44 Parameters of the Weibull distributions of visual wave height for the North Atlantic and North Sea are given in table B 1 and table B 2 Parameters of the Weibull distributions of visual wave height at weather stations A B C D E I J Kand M on the North Atlantic T in secs Hg and H in meters Ref 1
133. given a Pierson Moskowitz spectrum will be assumed EXAMPLES ASSIGN WAVE SPECTRUM SHAPE ASSIGN WAVE SPECTRUM SHAPE ASSIGN WAVE SPECTRUM SHAPE ASSIGN WAVE SPECTRUM SHAPE BMT GENERAL GAMMA 5 0 4 0 ALL DNV NA JONSWAP 3 3 0 07 0 09 ALL DNV WW PIERSON MOSKOWITZ ALL ISSC1 ISSC ALL El El El El SESAM Postresp Program version 6 2 15 DEC 2007 5 11 ASSIGN WAVE SPREADING FUNCTION WAVE SPREADING FUNCTION name sprnam ALL NONE PART hsl hsu tzl tzu PURPOSE To assign a wave energy spreading function to a wave statistics model The assignment will override the previous assignment PARAMETERS name sprnam ALL NONE PART hsl hsu tzl tzu EXAMPLES Name of the wave statistics model Name of the wave spreading function Wave spreading function will be assigned to the total area of the wave statistics model Long crested sea no wave spreading function Wave spreading function will be assigned to an area of the scatter diagram limited by the square made of Hsjywer HSupper and TSjower TS upper Lower limit of the significant wave height Hs Upper limit of the significant wave height Hs Lower limit of the zero upcrossing wave period Tz Upper limit of the zero upcrossing wave period Tz ASSIGN WAVE SPREADING FUNCTION NRD USER1 ALL ASSIGN WAVE SPREADING FUNCTION DNV NA COS2 PART 1 0 5 0 2 0 6
134. hases 0 to be uniformly distributed random varia bles on the range 0 27 mutually independent of each other and the amplitudes aj To ensure that n f has a Gaussian distribution for any number of frequencies the Fourier amplitudes a are taken as Rayleigh dis tributed random variables The contribution to the total mean square power E mO from frequency 0o is Postresp SESAM B 22 15 DEC 2007 Program version 6 2 then El a 7cos t 0 which reduces simply to E aj V2 Setting this result equal to c Ao in terms of the one sided power spectrum Sn m of n t we find E a 2S Ao 0 B 95 Equation B 95 provides the definition of the one parameter in the Rayleigh distribution for the Fourier wave amplitudes The total response x t of a second order Volterra system to input f equation G7 1 can be written as a sum of individual first and second order responses x 0 and x gt f The response may in general be a wave force or a structural response quantity The transformation from wave to response is defined by the first and second order transfer functions H m and H gt 01 03 Hi o is defined by i t 0 N x 0 Re Y ae H B 96 k 1 The sum and difference frequency second order transfer functions H gt 1 7 and H 01 03 are defined by N N x t qRe y by a aje k 11 1 i 0 t 0 9 i t 0 9 k L k 1 k l k I H 0 07 a aje H op 0 B 97 Int
135. he parameter is Tp peak period and not Tz Zero upcrossing period Postresp SESAM 5 52 15 DEC 2007 Program version 6 2 CREATE WAVE SPECTRUM USER SPECIFIED WAVE SPECTRUM name txt USER SPECIFIED freq dens PURPOSE To create a user specified spectrum where the user may give the energy density for selected frequencies These frequencies does not have to correspond to the frequencies given for the response variables For use in the statistical calculations note that the area of angular frequencies has to be the same area as given for the response variable it shall be combined with Maximum number of frequencies is 201 and they may be given in random order PARAMETERS name Name of the spectrum txt Descriptive text of the spectrum freq Input angular frequency dens Specified energy density for input frequency EXAMPLES CREATE WAVE SPECTRUM TESTSPEC USER SPECIFIED 0 1 1 0 2 1 0 3 1 0 4 1 0 5 digs 10060 Us OS 068 1089 LO e SESAM Program version 6 2 15 DEC 2007 CREATE WAVE SPREADING FUNCTION COSINE POWER WAVE SPREADING FUNCTION name txt USER SPECIFIED PURPOSE To create wave energy spreading for elementary wave directions Postresp 5 53 Postresp 5 54 15 DEC 2007 SESAM Program version 6 2 CREATE WAVE SPREADING FUNCTION COSINE POWER WAVE SPREADING FUNCTION name tx
136. he short term response option calculates the response of the structure based on an energy spectrum for a stationary sea state and the transfer function for the structure It is defined as the mean of one third of the largest responses in the response spectrum and it is divided by the significant wave height Note that the short term response for the second order drift forces is the expected value non harmonic The short term response is given as a function of T values full range calculation of wave spectra and it is determined by 4 Jmo 2 1 H S X173 where mg is the zero moment of the response spectrum for each T value and H is the significant wave height From this it follows that the short term response is given as the double amplitude response per signif icant wave height Note Itis not possible to calculate the short term response from a set of user defined wave spectra The short term response may be printed plotted or displayed as a function of the T values SESAM POSTRESP 6 2 01 15 APR 2004 Zero uperossing period s MEME Dw 0 0 PMI PH2I E HEME Dium45 0 PMI PM2I E MEAYE DiuecxBO 0 PMi PMZi Figure2 5 Short term response for HEAVE motion Postresp SESAM 2 8 15 DEC 2007 Program version 6 2 2 7 Short Term Statistics The short term statistics are available only through the PRINT command Two distribution methods are implemented Rayleigh and Rice Short term statistics are calculated for a given
137. hemselves AP The characters A B C and D in the examples above represent parameters being line mode COMMANDS written in upper case and numbers written in lower case All numbers may be entered as real or integer values Brackets are used to enclose optional parameters Postresp SESAM 5 2 15 DEC 2007 Program version 6 2 A parameter followed by a signifies a selection of one or more numerical values names or texts from a list of items In line mode this selection must be enclosed by parentheses Note Line mode commands are in this chapter presented in upper case including hyphens In graphics mode the commands appear in mixed case and without hyphens Note Graphics mode commands that are irrelevant at a given time are masked out shown grey in graphics mode Note The command END is generally used to end repetitive entering of data Using double dot rather than END to terminate a command will depending on at which level in the command it is given save or discard the data entered Generally if the data entered up to the double dot is complete and self contained the double dot will save the data If in doubt it is always safest to leave a command by entering the required number of END commands Use of Postresp in graphics mode is described in Section 4 5 Pull down menus and dialogue boxes of the graphic mode are shown in Appendix C Tutorial examples of line mode command input are giv
138. ile Assign Change Create Define Delete Display EE A he he he AE a he he he AA EE he he he de AE he he de r EE a he he he a he he de LAS RR E vede ode de he he he he hd EE de he he he he he EE he he he he he r r EE EE he he he he he he he he he he de he he he A he he hr EE he he he hr o EE EE he he hr eh he he he he he he he he de de de o AE he he he de dr EE he he he he dr o EE EE he he he hr EE w Print Run Select Set Help oo doo HE EE EE he he he he he he o A A A A A DELE A de de de de de de de de de de de de de de de de de de de de de de de de de de de de de de de de de de Program id Releese dete Access time User id POSTRESP Postprocessor for General Response Statistics r Marketing and Support by DNV Software 6 2 04 5 DEC 2007 14 DEC 2007 aarn Computer Impl update Operating system CPU id Installation P HH EH EE A HH HS HE EE EE EE he he he he he he he he he he hr 586 Win NI 5 1 2600 1981837515 DNVS OSLDP4242 Copyright DET NORSKE VERITAS AS P 0 Box 300 N 1322 Hovik Norway Figure C 1 POSTRESP dialogue window and commands SESAM Postresp Program version 6 2 15 DEC 20074
139. ility analysis and how to solve the equa tion of motion for a defined set of frequencies Section 3 11 contains the internal name convention For a quick introduction read Section 3 1 first 3 1 Short Introduction to how to use Postresp The most used commands in Postresp are CREATE PRINT DISPLAY and PLOT The CREATE command contains both subcommands for creating tools such as wave spectra and wave energy spreading functions and subcommands for creating response spectra and short or long term responses To give an illustration on a simple but very often used way of running Postresp the next items will show how to examine and make statistics on two response variables HEAVE and PITCH The numerical values used are taken from the example in Appendix A 1 FLOATING BARGE More detailed descriptions of some of the items are given in the following sub chapters We assume that the user has started Postresp with a new database file and that the prompt is offered a Read ina Global Response Results Interface File G file containing the transfer functions using the FILE READ command b Use the PRINT or DISPLAY commands to verify the data read from the G file Print or plot to file is ob tained by using the SET PRINT DESTINATION FILE or SET DISPLAY DESTINATION FILE com mand respectively Plots may also be obtained if the PLOT command is used after a display has been created The PLOT command directs the last display to a file or a connected p
140. in the terminal window and commands are typed on the input line There are two ways to start Postresp in line mode The Motif version can be run in line mode by adding 1 or line or L or LINE after the program name prompt gt postresp l VVhen Postresp starts it vvill give a heading first then prompt for a database file prefix name and status This is how it appears with a new database KKKKKK KKKKKK KKKKKK KKKKKK Kk KKK KkKKK KKKKKKKK KKKKKKKK KKKKKKKK KKKKKKKK KKKKKKKKKKKKK RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX KKKKKKK KKKKKKKKKK KkKKKKKK KKKKKKKKK RX RX RX KKKKKKK KKKKKKKKK KKKKKKK KKKKKKKKKK RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX RX KKKKKKKK KKKKKKKK KKKKKK KK KKKKKKKKK RX RX RX KkKKKKK KkKKKKK KKKKKK KkKKKKK KK RX RX RX KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK PO START En n HJ Postprocessor for General Response Statistics X KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK Marketing and Support by DNV Sesam Program id V N XY Computer DXXXXXX Release date DD MMM YYYY Impl update None Access time DD MMM YYYY HH MM SS Operating system XXXXXX User id XXXXX CPU id XXXXXX Account XXXXX Installation XXXXXX Special notes for this program version Graphics for VAXSTATION UIS and X WINDOW included Copyright DET NORSKE VERITAS SESAM AS P O Box 300 Database File Prefix Database File Name
141. ion The command DEFINE PRES ENTATION OPTION RESPONSE VARIABLE SECOND ORDER GRAPH is used to determine how the cut in the function is done See this command for a com plete description of the available options A maximum of 7 graphs can be presented together Name of second order response variable Postresp 5 94 dirl dir2 freq 15 DEC 2007 First wave direction for second order response variable Second wave direction for second order response variable Fixed frequency value SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 95 DISPLAY SECTIONAL FORCE DIAGRAM SECTIONAL FORCE DIAGRAM body dof dir freq Isec usec Froude PURPOSE Tp display a sectional force diagram as force moments against the section number For a ship vessel this will give the moment diagram over the ship length This is mainly used for ship models If several bodies selected only the first frequency or Froude number will be used PARAMETERS body Optional body identification Only available if DEFINE PRESENTATION OPTION SI MULTANEOUS BODIES is set to ALL dof Degree of freedom for which the sectional force diagram will be displayed dir Wave direction for the transfer function freq Selected angular frequencies Isec Lower sequence number on the sectional forces This requires a sequence numbering from the Global Response Interface File usec Upper
142. ion are dependent on both frequency and direction Running the equation of motion the motion response variables will be updated while the matrices them selves will NOT be affected The purpose is to enable the user to introduce additional frequencies when ana lysing the transfer functions Two examples are given below In the first example it is assumed that the response variables are given for wave directions 0 45 and 90 degrees and a calculation of response variables for two additional frequencies 0 299 and 0 4 is requested RUN EQUATION SOLVER 0 45 90 0 299 0 4 In the second example the equation of motion is solved for all original directions and frequencies This option is used typically when some of the coefficient matrices are changed by the CHANGE MATRIX com mand In the example below the body mass is set to 1000 and the response variables are re calculated for the new body mass for all wave directions CHANGE MATRIX BODY MATRIX 11 1000 22 1000 33 1000 RUN EQUATION SOLVER ORIGINAL FREQUENCIES 3 8 Workability Analysis Workability analysis 1s done by giving the command CREATE WORKABILITY ANALYSIS name descr resp rmsall dir where rmsall is the allowable double amplitude level for response variable resp Before running the workability analysis the user must assign wave statistics models only scatter diagrams to each wave direction to be used The wave spectrum shapes and wave s
143. ion of this spectrum is re stricted to creation of response spectrum generation of short term statistics and print and display of the spectrum GENERAL GAMMA with input of the significant wave height H the zero upcross ing period T and the parameters I and n When 155 and n 4 the general gamma spectrum will correspond to a Pierson Moskowitz spectrum SESAM Postresp Program version 6 2 15 DEC 2007 2 3 Wove spectrum used in response soeciro Wove Spectrum as 0 20 o 0 15 Energy density llee2 eel 1 0 E Angulor Frequency trod e Poroneter value 1 0 Hs Tz 10 0 P 0 44651 Figure 2 2 Pierson Moskowitz spectrum for Hz 1 0 m and Ts 10 sec If another spectrum type is required the user has to type in each angular frequency and the corresponding ordinate value Linear interpolation will be applied between the spectral ordinates specified The print of a wave spectrum contains the spectrum parameters It is possible to dump out the spectrum val ues for a given spectrum name A wave spectrum may also be displayed or plotted except the general gamma spectrum 2 3 Wave Energy Spreading Functions The wave energy spreading functions are used when statistical calculations are required for short crested sea i e if the user wants to take into account other directions than the current main wave direction The wave spreading functions may only be used if the available wave directions cover 180 degrees or
144. itle Default C Specified Limits Free C Fixed Spacing Linear Decimal Format General v Title Default C Specified Apply Cancel OK Apply Cancel Ill Graph ZAxis Attributes X m Print Options Limits Free Destination Screen Fixed Page Orientation Portrait gt Spacing Linear Page Height Decimal Format General v Screen Height Title Default File Prefix Specified Name ETS OR Apply Cancel ME Histogram Options x ME Set Title Filling Sold gt Columns soy Cancel Figure C 59 SET GRAPH XAXIS ATTRIBUTES GRAPH YAXIS ATTRIBUTES GRAPH ZAXIS ATTRIBUTES GRAPH HISTOGRAM TITLE SESAM Postresp Program version 6 2 15 DEC 20074 C 51 NE Plot Options LI n Figure C 60 SET PLOT C13 HELP Menu ME POSTRESP 6 2 04 Figure C 61 HELP pulldown menu Postresp SESAM C 52 15 DEC 2007 Program version 6 2 MM POSTRESP 6 2 04 File Assign Change Create Define Delete Display Print Run Select Set Ma pos sesan Support User Manuals on web Status Lists on web Status List program Command Input File Defaults Programming Mode Selecting Other facilities Figure C 62 HELP LINE MODE pulldown menu ME POSTRESP 6 2 04 Fie Assign Change Create Define Delete Display Print Run Select Set Ea About SESAM About Help Support User Manuals on web Status Lists on web Status List program Command Input File
145. lable box The default status will be set to Insert before The input fields will be SESAM Postresp Program version 6 2 15 DEC 2007 4 19 Clear Clear the contents of the matrix Note that there is no way to get the cleared contents back other than perhaps cancelling the dialogue box and opening it again Help Pressing this is equivalent to pressing the help button while the scrollable box has the input focus It provides on line access to a description of how to use the matrix vector 4 5 7 Journalling from Graphics Mode All commands that are accepted from the graphics mode are logged on the journal file The commands are logged in a format that can be read into the corresponding line mode command There is one case that deserves attention Some dialogue boxes contain many line mode commands An example is the Define Presentation Option dialogue box Since all the visible contents of a dialogue box are selected when the OK or Apply button is pressed even if only parts of the box has been changed all possible commands in the box will be logged Define Presentation Option x Simultaneous Bodies Singe v Abscissa Axis Period v Response Variable Ordinate Values f mpitude v Ordinate Units Radians he Second Order Graph Direction to be fixed First Direction v Contour Levels Low Figure 4 13 The Define Presentation Option dialogue box Pressing the OK or Apply button in this box will generate the foll
146. le at the y axis can be specified by Postresp DEFAULT or overridden with a SPECIFIED text lt ytitle gt The following options are default when Postresp starts up with a new database SET SET GRAPH SET SET GRAPH E p pd pd 3 3 El HJ GRAPH GRAPH YAXIS ATT YAXIS ATT YAXIS ATT YAXIS ATT RIBUTES DECIMAL FORMAT GENERAL RIBUTES LIMITS FREE RIBUTES SPACING LINEAR RIBUTES TITLE DEFAULT SESAM Program version 6 2 Postresp 15 DEC 2007 5 143 SET GRAPH ZAXIS ATTRIBUTES ZAXIS ATTRIBUTES LIMITS EXPONENTIAL FIXED GENERAL INTEGER FREE FIXED zmin zmax LINEAR LOGARITHMIC DEFAULT SPECIFIED ztitle DECIMAL FORMAT SPACING TITLE PURPOSE Set options controlling the attributes of the z axis in a graph PARAMETERS DECIMAL FORMAT LIMITS SPACING TITLE EXAMPLES Controls the presentation of numbers labelling the z axis The numbers can be pre sented in EXPONENTIAL format in FIXED format as INTEGERs or in GENER AL free format Controls the limits of the z axis These can either be FREE i e determined by the data that are being presented or FIXED to the min value lt zmin gt and the max value lt zmax gt Controls the spacing of numbers along the axis The axis can have a LINEAR spac ing or be LOGARITHMIC with base 10 The title at the z axis can be speci
147. lines read are echoed on the screen and logged in the journal file Programming expressions are logged as comments and the resulting values are logged as part of the command The command itself is not logged on the journal file If an error is found inside a command input file Postresp stops reading the file and skips the remaining part of the line where the error was found Postresp will also stop reading a command input file if it finds a line containing only an The commands used to manipulate command input files are summarized below filename Read the named file from the top Reading will stop if an error is found or at the end of the file or if a line with only an is found There may be one or more blank spaces between a and the filename filenamen Read n lines from the starting of the named file Reading will stop if an error is found or if a line with only an is found There may be one or more blank spaces between a and the filename Continue reading the presently open file Reading will stop if an error is found or at the end of the file or if a line with only an is found n Continue reading n lines from the presently open file Reading will stop if an error is found or at the end of the file or if a line with only an A 1s found Close the last opened command input file There cannot be any blank space between and the dots Show the name and status of the currently open command input file
148. ll be printed A single element of the matrix will be printed as a function of the angular frequencies Optional body identification Only if a multiple body solution is executed Both the body matrix and the coupling matrices are available Selected angular frequency Element number in the matrix The number must be specified as 2 digits giving the row and column number in a 6x6 matrix For instance the heave heave element will be referred as 33 SESAM Postresp Program version 6 2 15 DEC 2007 5 113 PRINT OVERVIEW ALL LONG TERM RESPONSE MATRIX OVERVIEW RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE SHORT TERM RESPONSE SPECIFIC POINT WAVE SPECTRUM WAVE SPREADING FUNCTION WAVE STATISTICS WORKABILITY ANALYSIS PURPOSE This command gives a table containing an overview of the total number of each response available in the Postresp data base or an overview of each object with names and descriptive text PARAMETERS ALL LONG TERM RESPONSE MATRIX RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE SHORT TERM RESPONSE SPECIFIC POINT WAVE SPECTRUM WAVE SPREADING FUNCTION Global overview of total number of each response available in the current data set Also print any text records read from the Response Interface File Overview of the long term responses created Overview of the global matrices Overview of the cross spectra
149. logue box it is possible to get help on the item that currently has the input focus by press ing the Help key F1 on most systems where there is no help key The help text will appear in the message area There is also a Help menu under the main menu which contains much useful on line information 4 5 3 Dialogue Boxes and their Contents A dialogue box is used to pass information from the user to Postresp Most dialogue boxes also present the current defaults and thus may be used to pass information from Postresp to the user The typical entries in a dialogue box are Input fields Menus and Push buttons Drawing Options xi fme Character Type Software v Font Type Simle v Font Size Relative gt Size factor Apply Cancel Figure 4 9 The Set Drawing dialogue box An input field can contain a text a name an integer value or a numerical value The Create Wave Spectrum dialogue box contains two input fields the name and the description To type into the field click in it first using the left mouse button In some input fields the text can be longer than the width of the field as shown in the dialogue box The text will then scroll if typed beyond the width of the input field Postresp SESAM 416 15 DEC200 Program version 6 2 Nare Spectrum Type General Gamma v Single or Full Range Scatter Diagram hd Wave Scatter Diagram Apply Cancel Figure 4 10 The Create Wave Spectrum dialogue box
150. long as the structure does not have any forward speed and as long as the phase information is of no interest Postresp SESAM 4 12 15 DEC 2007 Program version 6 2 4 5 Details on Graphics Mode 4 5 1 Graphics Environment The Postresp graphics environment offers a main window with the following parts from top to bottom Title bar This gives the name and version of the program that 1s being run Main menu This bar of pull down menus gives access to all the commands of Postresp Shortcut buttons This gives access to general tools described below Message area This is used to display messages and information plus the commands that have been typed into the command input line as well as those that have been read from command input files Command input line This line is used to type line mode commands All facilities that are described in Section 4 6 are available through this line It is initialised by the shortcut button Display area This area 1s used to display graphs and other graphic information The shortcut buttons are as follows m Prints status list for Postresp The status list is logged on the print file status mlg Toggles command input mode on and off Tl Reads command input file The file must have the extension jnl Cuts selected text to the clipboard Bi Copies selected text to the clipboard Pastes text from the clipboard SESAM Postresp Program version 6 2 15 DEC 2007 4 1
151. lot col our options may be different Show the display on the SCREEN or send it to a FILE Set the display device If the device is not correct the display will appear as a lot of strange characters on the screen and probably demand that a lt Return gt is typed before it appears The display device is ignored if the display destination is to file The actual list of available devices depend on the installation Some but not necessarily all of these could be available 3279 APOLLO CDC 721 TPAZ MONO TPAZ COLOUR TX4014 15 16 54 TX4105 TX4107 09 13 15 VT125 VT240 VT340 WESTWARD 3219 VESTVVARD 3220 VAXSTATION UIS X WINDOW DUMMY The DUMMY device is used to do a display command without generating a display Set the size of the display window This command will only work when running under X windows and on an Apollo work station In addition the window size must be set before the win dow is opened The left edge of the window Must be in the range from 1 to 120 Postresp SESAM 5 136 15 DEC 2007 Program version 6 2 right The right edge of the window Must be in the range from to 120 bottom The bottom edge of the window Must be in the range from 1 to 100 top The top edge of the window Must be in the range from 1 to 100 NOTES The DESTINATION FILE option is useful for making a journal file run in batch mode Edit the setting into the top of the file and all displays will be written to file instead
152. lue of significant wave height Minimum value used is 1 0 meter ah Parameter defining the relationship between significant wave heights and visual wave heights SESAM Postresp Program version 6 2 15 DEC 2007 5 27 bh Parameter defining the relationship between Hs and Hv steep Steepness criteria ming Minimum probability level of which the value of x is requested for the long term distribution of x The value is given as an absolute integer exponent i e Q x 1074 maxq Maximum probability level of which the value of x is requested for the long term distribution of x incr Step in absolute exponent Postresp SESAM 5 28 15 DEC 2007 Program version 6 2 CREATE LONG TERM FATIGUE LONG TERM RESPONSE RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE SHORT TERM RESPONSE SPECIFIC POINT SPEED REDUCTION CURVE WAVE SPECTRUM WAVE SPREADING FUNCTION WAVE STATISTICS WORKABILITY ANALYSIS CREATE PURPOSE The create command is the main command for creation of statistical data and the tools which may be used in the statistical operations The user may in the frequency domain create different tools such as wave spectra wave energy spreading functions or wave statistics models and then select among these to calculate response spectra short term responses short term statistics or long term responses SESAM Postresp Program version 6 2 15 DEC 2007 5 29 CREATE L
153. m The Gamma spectrum may be written as S Ao e SESAM Program version 6 2 B 12 B 13 B 14 B 15 B 16 B 17 where A B and n are parameters of the spectrum The parameter 4 is a scale parameter of the wave fre quency o The parameter B determines the overall level of the spectral density and thus indicates the general severity of the seastate The third parameter determines the asymptotic behaviour of the high frequency tail of the spectrum and the fourth parameter n influences the low frequency flank and also the sharpness of the peak The parameters A and B may be expressed in terms of the seastate parameters H and T i e 1 3 2 re ae n 16 T l 1 EE pc n 21 Re 7 where I denotes the gamma function B 18 B 19 The Pierson Moskowitz spectrum is a special case of the Gamma spectrum with parameters 5 and m 4 SESAM Postresp Program version 6 2 15 DEC 2007 B 5 B 1 5 ISSC Spectrum The ISSC International Ship and Offshore Structure Congress spectrum may be written as S B 20 E EL Ex Hio OR where H is the significant wave height and w is the mean wave frequency which is related to the mean wave period T by 2n o T B 21 The mean wave period T is defined by ap B 22 my The mean wave period T is related to the mean zero up crossing period T by LX LA seri 1 086435 B 23 o GOR 0 44347 B 24 B1
154. m response SESAM Postresp Program version 6 2 15 DEC 2007 5 59 hsmax Maximum value of significant wave height Minimum value used is 1 0 meter ah Parameter defining the relationship between significant wave heights and visual wave heights bh Parameter defining the relationship between Hs and Hv steep Steepness criteria Postresp SESAM 5 60 15 DEC 2007 Program version 6 2 CREATE WAVE STATISTICS SCATTER DIAGRAM WAVE STATISTICS name txt SCATTER DIAGRAM PROBABILITY hs tz prob OCCURENCE hs tz occ PURPOSE To create wave statistics model for use in the long term response calculation The wave statistics model describes the sea state conditions during a long term period and consists of mainly Tz and Hs values and their probability of occurrence By this command the wave statistics model is given through a scatter dia gram PARAMETERS name Name of the wave statistics txt Descriptive text for the model PROBABILITY Each sea state 1 e cell in the diagram will be given a probability of occurrence OCCURENCE Each sea state i e cell in the diagram will be given as number occurrences during the long term period hs Significant wave height Hs tz Zero upcrossing period Tz prob Probability for given zero upcrossing period Tz and significant wave height Hs occ Occurrence of the seastate given the zero upcrossing period Tz and significant wave height Hs
155. mber amp amp amp and degree of freedom FRCSUM Transfer function for second order excitation forces at sum frequencies FRCSUMI force in x direction FRCSUM2 force in y direction FRCSUM3 force in z direction FRCSUMA moment about x axis FRCSUMS moment about y axis FRCSUM6 moment about z axis FRCDIF Transfer function for second order excitation forces at difference frequencies FRCDIFI force in x direction FRCDIF2 force in y direction Postresp SESAM 3 12 15 DEC 2007 Program version 6 2 FRCDIF3 force in z direction FRCDIF4 moment about x axis FRCDIFS moment about y axis FRCDIF6 moment about z axis When calculating response spectra Postresp automatically generates identification numbers The number ing system is given in table 3 1 It is illustrated by an example Input all rigid motions 2 headings 0 and 90 degrees 3 wave spectra FRPM1 FRPM2 FRPM3 I wave spreading function COS2 Table 3 1 NO RESPONSE VARIABLE WAVE SPECTRUM HEADING SPREADING 1 HEAVE FRPMI 0 COS2 2 HEAVE FRPMI 90 COS2 3 HEAVE FRPM2 0 COS2 4 HEAVE FRPM2 90 COS2 5 HEAVE FRPM3 0 COS2 6 HEAVE FRPM3 90 COS2 7 PITCH FRPMI 0 COS2 8 PITCH FRPMI 90 COS2 9 PITCH FRPM2 0 COS2 10 PITCH FRPM2 90 COS2 11 PITCH FRPM3 0 COS2 12 PITCH FRPM3 90 COS2 13 ROLL FRPMI 0 COS2 ROLL FRPMI 0 COS2 19 SURGE FRPMI 0 COS2 SURGE FRPMI 0 COS2 25 SWAY FRPMI 0 COS2
156. mmand input file A colon or semicolon is never logged on the journal file Instead the substituted default value s is logged When a numerical default is available it will be stored in the calculator as a variable under the name default so that it may easily be modified See the note at the end of Section 4 6 3 about this 4 6 5 Abbreviation and Wildcards Postresp offers two methods to shortcut selection of elements in a list Abbreviation and the use of wild cards Abbreviation of alternatives up to hyphens is allowed as long as the abbreviation is unique Thus LONG TERM RESPONSE may be abbreviated to any of LONG L T R L TERM RES L L RES as long as the abbreviation is unique between the alternatives presented Wildcards consist of the following two characters substitutes for any number of characters It also matches nothing amp substitutes for any one character It must match exactly one character As an example x y amp amp matches xabycc1 and xy111 but not xaby11 Abbreviation and wildcards may not be mixed in the same matching expression For example RESP will not match LONG TERM RESPONSE 4 6 6 Input of a Text or Name or Numerical Value Numerical values can be input in free format in Postresp Floating point numbers as 1000 1 54 le 44 1e5 are all accepted Integers can be specified as floating point numbers as long as the decimal part vanishes Examples of whole numbers 1000 1 1e4 Names can
157. mple of this is entering parameter values in the DEFINE RETURN PERIOD command The term matrix is used for the case where the input is multidimensional An example of this is the input of a user defined wave spectrum where the frequencies and weights form a two dimensional matrix Like a vector is built up from single items a matrix is built from rows All columns of a matrix must have the same number of items The input of a vector matrix consists of one or more operations If more than one operation is required as it most likely will be they must be enclosed in parenthesis The syntax of one operation is row refers to a single value in a vector or to a row in a matrix INCLUDE row Include the specified row as the last row Set the default status to INCLUDE Until the status is changed rows that are entered will be added at the end EXCLUDE row Exclude the specified row Set the default status to EXCLUDE The next row s that are entered will also be excluded until the default status is changed Wildcards may be used to specify row All matching rows will be excluded SESAM Postresp 15 DEC 2007 4 27 Program version 6 2 ONLY row INSERT BEFORE row1 row2 OVERWRITE rowl row2 LIST Include only row in the matrix clearing any previous contents first Set the default status to INCLUDE Until the status is changed rows that are entered will be added at the end Insert row1 before row2 Set the default status to INSER
158. n Wild card specification is available Response variable for combined displacement of the point will be generated Response variable for combined velocity of the point will be generated Response variable for combined acceleration of the point will be generated Relative motion compared to sea surface elevation in vertical direction below or above the given specific point Absolute motion will be generated The degree of freedom of the generated response variable Relative motion only in z direction CREATE RESPONSE VARIABLE AG1 Air gap COMBINED MOTION PF ONLY HEAVE PITCH ROLL SURGE SWAY YAW DISPLACEMENT RELATIVE Z SESAM Postresp Program version 6 2 15 DEC 2007 5 35 CREATE RESPONSE VARIABLE FIRST DERIVATED RESPONSE VARIABLE name tx ec FIRST DERIVATED resp PURPOSE To create a the first derivative of a selected response variable The response variable will be created by mul tiplying each amplitude by its angular frequency i e the real and imaginary part is multiplied by io PARAMETERS name Name of the response variable txt Descriptive text of the response variable resp Name of the response variable to be included in the combination Postresp SESAM 5 36 15 DEC 2007 Program version 6 2 CREATE RESPONSE VARIABLE GENERAL COMBINATION RESPONSE VARIABLE name txt GENERAL COMBINATION resp fact
159. n 6 2 SESAM Program version 6 2 15 DEC 2007 DELETE WAVE SPREADING FUNCTION WAVE SPREADING FUNCTION name PURPOSE To delete a wave energy spreading function PARAMETERS name Name of the function Postresp 5 83 Postresp 5 84 15 DEC 2007 DELETE WAVE STATISTICS WAVE STATISTICS name PURPOSE To delete a wave statistics model PARAMETERS name Name of the wave statistics SESAM Program version 6 2 SESAM Program version 6 2 15 DEC 2007 DELETE WORKABILITY ANALYSIS WORKABILITY ANALYSIS namet PURPOSE To delete a workability analysis PARAMETERS name Name of the workability analysis Postresp 5 85 Postresp SESAM 5 86 15 DEC 2007 Program version 6 2 DISPLAY LONG TERM RESPONSE MATRIX REFRESH RESPONSE CO SPECTRUM RESPONSE SPECTRUM RESPONSE VARIABLE DISPLAY SECTIONAL FORCE DIAGRAM SHORT TERM RESPONSE SN CURVE SPECIFIC POINT SPEED REDUCTION CURVE WAVE SPECTRUM WAVE SPREADING FUNCTION m PURPOSE To display selected functions or spectra on a graphical screen The screen device may be altered by the SET DISPLAY DEVICE command SESAM Program version 6 2 Postresp 15 DEC 2007 5 87 DISPLAY LONG TERM RESPONSE LONG TERM RESPONSE SLAMMING LOG Q dirt RESPONSE VARIABLE body respt WAVE DIRECTION _ prob LOG Q dirt bo
160. n 6 2 SESAM POSTRESP 6 1 01 26 NOV 1993 Long term response for HEAVE Long Term Response Probability level 6 0000 o Q c o a o o ca 200 Wave Direction Response Variable AX HEAVE SESAM Program version 6 2 Postresp 15 DEC 2007 A 27 SESAM POSTRESP 6 1 01 26 NOV 1993 o o o a Q oO 4 Long term response for PITCH Long Term Response 10 Log i6 Prob Response Voricble n PITCH mta PITCH El PITCH 7 PITCH Dir 0 0 Dir 45 0 Dir 90 0 ALL Inc Postresp SESAM A 28 15 DEC 2007 Program version 6 2 SESAM POSTRESP 6 14 04 26 NOV 1993 Long term response for PITCH Long Term Response Probobility level 6 0000 o a c a Q o o c 200 Wove Direction Response Variable lA PITCH SESAM Postresp Program version 6 2 15 DEC 2007 B 1 APPENDIX B THEORY AND FORMULATION B1 SHORT TERM DESCRIPTION OF SEA In a short term description of the sea the statistical properties of the waves are treated as being invariant over a period lasting a few hours The sea surface is regarded as the sum of an infinite number of elementary sinusoidal waves with different frequencies and directions and with random phase angles The distribution of wave energy according to the frequencies of the wave components is represented by a wave spectrum B1 1 Wave Energy Spreading Function Short crested waves are the combination of different long crested waves from different directions The wave
161. n provided by the statistical model above relates to the most probable largest value and when viewed within extreme value statistics this value has a 63 chance of being exceeded SESAM Postresp Program version 6 2 15 DEC 2007 B 21 B6 Theoretical Background for Second Order Statistics B6 1 Introduction The output x t of a second order Volterra system to input n is given in terms of the first and second order transfer functions by i ogt O N x t Re gt a e H k 1 B 91 N N _ 0 0 j 6 0 qRe Y y age i opt 0 6 il o opt 6 ale k 11 1 H Op 07 a a e where a and 0 are the Fourier amplitudes and phases of the input n q will be discussed below The objective is to calculate the statistical moments of x t The stochastic nature of the input n is represented by the fact that a and 0 in Equation B 91 are random variables The approach will be to transform the dis crete sinusoidal components into uncorrelated standard normal processes With x f written in this way the moments of x t will be more easily computed B6 2 Problem Transformation The wave elevation n f is first written as a discrete Fourier sum over positive frequencies 0 N n r Re V a cos o 1 0 B 92 k 1 Equivalently we may write i t 0 N n t Re p a e B 93 k 1 Or N j 0 i t 0 n t 23 me Di aye mt d Bh k 1 The stochastic nature of n is captured by taking the p
162. nce sum or both frequencies shall be included In the example below excitation force in vertical direction main wave direction 0 degrees a wave spectrum named FRPM10 and a wave spreading function COS2 is selected The probabilities of exceedance is 0 001 0 0001 and 0 00001 PRINT SECOND ORDER STATISTICS DIFFERENCE SECOND ORDER ONLY EXCITATIONFORCE 3 FRPM10 COS2 0 0 001 0 0001 0 00001 3 10 Calculation of Stochastic Fatigue The fatigue damage is printed for a set of short term durations given in seconds of given sea states actu ally for given response spectra in this case no 1 and a given SN curve by execution of the command PRINT SHORT TERM FATIGUE ONLY 10800 ONLY 1 DNV X The total damage for each duration and response spectrum is then presented in a print table The short term fatigue calculation assumes Rayleigh distribution of the stress ranges Long term fatigue can be calculated based directly on a scatter diagram where Rayleigh distributions are assumed for each cell The fatigue results are then first calculated and stored by the command CREATE LONG TERM FATIGUE ONLY GRES1 ONLY 0 0 45 0 90 0 DNV X The results can then be printed by giving the command PRINT LONG TERM FATIGUE ONLY GRES1 ONLY 108000 SUMMARY The total damage and the contribution to damage from each cell in the scatter diagram and for each direction is then pri
163. nd into another Command It is possible to insert a command at any point while in command mode not in programming mode This is done by simply typing the main prompt followed by the inserted command Postresp will finish the new command and then return to the point in the previous command where the new command was inserted This is useful e g for catching up on settings or definitions that was forgotten while inside a PRINT or DIS PLAY command or for printing out objects to see what they contain The following examples illustrate this DISPLAY RESPONSE VARIABLE DEFINE PRESENTATION OPTION Define Presentation Option ABSCISSA AXIS PERIOD Name HEAVE The same command cannot be entered recursively e g it is not allowed to inserta CHANGE RESPONSE VARIABLE command inside another CHANGE RESPONSE VARIABLE command Commands can be nested this way to as many levels as desired However to nest with more than one level may be confusing and is not recommended The current status may be seen by typing This facility is described in Section 4 6 14 SESAM Postresp Program version 6 2 15 DEC 2007 4 29 4 6 12 Aborting all or parts of a Command To abort a command type two dots Please note that all entries on the command line up to the double dot will be processed before the command is aborted The double dot clears all loops and previous input in the command and then presents the main prompt A double dot is not logge
164. nd segment Arbitrary tail m Slope of second segment M1 Third segment abiaytil Log cycles at end second segment logN1 Slope of third segment M2 Close Figure C 21 CREATE SHORT TERM RESPONSE SN CURVE Postresp SESAM C 20 15 DEC 2007 Program version 6 2 ME Create Specific Point x ME Speed reduction curve Name Description Coordinate Y Coordinate Hs Froude Z Coordinate Apply Cancel Name Description Significant wave height ME Create Wave Spectrum Froude number Name E Overwrite Description Insert before Clear Help Spectrum Type Ochi Hubble Range Alternative Single Hs swell OK Apply Cancel Tp swell Shape swell ME Create Spreading Function Hs wind Tp wind Name Shape wind Description Type Cosine Power v OK Apply Cancel Cancel Figure C 22 CREATE SPECIFIC POINT SPEED REDUCTION CURVE WAVE SPREADING FUNCTION WAVE SPECTRUM Ochi Hubble SESAM Program version 6 2 ME Create Wave Spectrum Name Description Spectrum Type JONSWAP Scatter Diagram m Single or Full Range Wave Scatter Diagram Gamma Sigma Sigma B Cancel Postresp 15 DEC 20074 C 21 x ME Create Wave Spectrum Name Description Spectrum Type Pierson Moskowitz v Single or Full Range Single s T Cancel Figure C 23 CREATE WAVE SPECTRUM Jonswap Pierson Moskowitz Postresp SESAM C 22 15 DEC 2007 Program version 6 2 ME
165. nerated spectra will be maximum minimum increment I SCATTER DIAGRAM A set of wave spectra are generated based on the T1 values with Hs values equal SINGLE hs tl EXAMPLES CREATE WAV E SPI EC CREATE WAVI E SPI ECT to 1 for the wave scatter diagram assigned to the corresponding wave spectrum shape A single wave spectrum is generated Significant wave height Hs Mean wave period T1 RUM ISSCSNGL Hs 8m Tl 0s ISSC SINGLE 8 10 TRUM ISSCFULL T1 10 to T1 20 ISSC FULL RANGE 10 20 0 5 SESAM Program version 6 2 Postresp 15 DEC 2007 5 47 CREATE WAVE SPECTRUM JONSWAP WAVE SPECTRUM name txt JONSWAP tzmin tzmax incr HS TZ gamma sigmaa FULL RANGE sigmab p frmin p frmax ALPHA OMEGAP incr gamma sigmaa sigmab SCATTER DIAGRAM gamma sigmaa sigmab HS TZ hs z enue sigmaa sigmab SINGLE alpha p freq ALPHA OMEGAP gamma sigmaa sigmab PURPOSE To create wave spectra based on a JONSWAP spectrum type PARAMETERS name txt FULL RANGE HS TZ hs tz ALPHA OMEGAP Name of the spectrum Descriptive text of the spectrum If FULL RANGE the 20 first letters will be used in addition to the internal text generation e g Tz 10 0 Full range calculation of JONSWAP spectra Le wave spectra with Hs equal to 1 0 and different Tz values given as a
166. nge calculation incr Increment between tzmin and tzmax Total number of generated spectra will be maximum minimum increment 1 SCATTER DIAGRAM A set of wave spectra are generated based on the Tz values with Hs values equal to 1 for the wave scatter diagram assigned to the corresponding wave spectrum shape SINGLE A single wave spectrum is generated hs Significant wave height Hs tz Zero upcrossing wave period Tz Postresp 5 46 SESAM 15 DEC 2007 Program version 6 2 CREATE WAVE SPECTRUM ISSC WAVE SPECTRUM name txt ISSC FULL RANGE tl min tl max incr ISSC SCATTER DIAGRAM SINGLE hs tl PURPOSE To create wave spectra based on a ISSC spectrum type PARAMETERS name txt FULL RANGE tlmin tlmax incr Name of the spectrum Descriptive text of the spectrum If FULL RANGE the 20 first letters will be used in addition to the internal text generation e g T1 10 0 Full range calculation of ISSC spectra Le wave spectra with Hs equal to 1 0 and different T1 values given as a range will be generated This alternative will create internal names which will be prfx where prfx is the first 4 letters of the name given and is an integer number in increasing order see Section 3 3 Minimum value of T1 for full range calculation Maximum value of T1 for full range calculation Increment between tzmin and tzmax Total number of ge
167. nly in connection with PAGEO RIENTATION LANDSCAPE EXAMPLES The following options are default when Postresp starts up with a new database SET PRINT DESTINATION SCREEN SET PRINT FILE the prefix and name of the database and journal file are defaults SET PRINT SCREEN HEIGHT see NOTES above SET PRINT PAGE ORIENTATION PORTRAIT Postresp SESAM 5 148 15 DEC 2007 Program version 6 2 SET TITLE TITLE text 4 PURPOSE Set user defined titles to be used with print and display plot PARAMETERS text Give four lines defining the plot title The display layout will not accept more than 40 char acters in each title NOTES The user titles are blank when Postresp starts up with a new database EXAMPLES SET TITLE Project name Analysis no 2 Line 3 Line 4 SESAM Postresp Program version 6 2 15 DEC 2007 A 1 APPENDIX TUTORIAL EXAMPLES A1 FLOATING BARGE This example shows the use of the most common features in Postresp That is defining statistical tools such as wave spectra wave spreading functions and long term wave statistics and generation of response spectra short term responses and long term responses The global results used in this example is generated by Wadam A panel model is used for a simple floating barge with a total length of 50 meters and a distributed mass model taken from the panel model The transfer functio
168. ns on the Results Interface File are given for the following response variables 6 first order rigid body motions 6 first order wave exciting forces 10 sections with 6 force components on each section That is 60 sectional loads All these transfer functions are given for 20 wave lengths from 46 75 to 881 14 meters These values are incremented logarithmic because this run has been used to compare Postresp results with the old statistical program NV1473 which requires a logarithmic wave length spacing 5 wave directions 0 45 90 135 and 180 degrees Further main input data used are e Water depth 250 meters Characteristic length 50 meters Two response variables have been used in the example HEAVE and PITCH motion The response spectra short term responses and the long term responses have been calculated and both printed and plotted Some of the statistical tools defined and used are also printed and plotted The journal file used and the print and plots generated are given on the following pages Postresp SESAM A 2 15 DEC 2007 Program version 6 2 Postresp Users Manual tutorial example Al o do do oe Create wave spreading function named COS2 CREATE WAVE SPREADING COS2 COS 2 Create a set of Pierson Moskowitz spectra for Tz 5 0 to 15 0 seconds The spectra will be named FRPM1 FRPM2 FRPM21 CREATE WAVE SPECTRUM FRPM PIERS
169. nsfer functions for different global results and will be used in the frequency do main part of Postresp This file may also be created by other programs in that case note that there are some records in this file which are mandatory such as WGLOB DEF WBODCON and WDRESREF The Results Interface File may in frequency domain be of any format FORMAT TED UNFORMATTED or DIRECT ACCESS often named SIN file In time do main it is required that the Results Interface File is given on DIRECT ACCESS format If the file contains time series the time domain extension of Postresp must be used described in a separate user manual Command Input This file is used to read commands and data into Postresp The usage of command input files is described in Section 4 6 2 The default extension of a command input file is jnl but this default is not used if another extension is specified Print The print file is used to keep output from the PRINT command when the print des tination is set to file The extension of the print file is lis The print file name and settings is specified using the command SET PRINT It is possible to use more than one print file during the same Postresp session but only one can be open at a time Plot The plot file is used to keep output from the PLOT command and from the DIS PLAY command when the display destination is set to file The plot file name and settings is specified using the command SET PLOT The extension
170. nstalljac launching of jackets ENVIRONMENTAL ANALYSIS SESAM INTERFACE FILE Sestra linear statics and dynamics Ci STRUCTURAL ANALYSIS GeniE conceptual modeller including VVajac Sestra Splice Framework Figure 1 1 Postresp in the Sesam System Wajac wave loads on frame structures Wasim 3D wave loads on vessels Splice structure pile soil interaction Usfos progressive collapse DeepC deep water mooring and riser analysis including Simo Riflex POSTPROCESSING HydroD environmental modeller including Wadam Wasim Postresp SESAM Program version 6 2 Postresp presentation of statistical response Framework frame design Stofat shell plate fatigue Profast probabilistic fatigue and inspection Cutres presentation of sectional results Platework plate design SESAM Postresp Program version 6 2 15 DEC 2007 1 3 1 3 Hov to read this Manual Chapter 2 FEATURES OF POSTRESP gives a description of the program features Chapter 3 USER S GUIDE TO POSTRESP explains the program organization with particular descriptions of some of the calculation steps including some examples This chapter also contains a description of the internal name conventions Chapter 4 EXECUTION OF POSTRESP explains the file types starting procedures the Graphical User Interface and some program requirements and limitations Chapter 5 COMMAND DESCRIPTION contains a d
171. nt i e Q x 10 log Q Postresp SESAM 5 66 15 DEC 2007 Program version 6 2 DEFINE PRESENTATION OPTION SINGLE SIMULTANEOUS BODIES ALL ANGULAR FREQUENCY PRESENTATION ENCOUNTER FREQUENCY OPTION ABSCISSA AXIS PERIOD WAVE LENGTH RESPONSE VARIABLE CONTOUR LEVELS Low High Step DEGREES ORDINATE UNITS RADIANS AMPLITUDE ORDINATE VALUES PHASE AMPLITUDE REAL IMAGINARY FIRST DIRECTION SECOND DIRECTION FIRST DIRECTION SUM SECOND DIRECTION SECOND ORDER GRAPH DIFFERENCE FIRST DIRECTION DIFFERENCE SECOND DIRECTION SUM PURPOSE To define presentation options for the graphic or print presentation PARAMETERS SIMULTANEOUS BODIES ABSCISSA AXIS Switch between access to a SINGLE body the currently select ed body or ALL available bodies in the same graph Selecting ALL will generate a prompt for body selection in the DIS PLAY command Switch between ANGULAR FREQUENCY wave PERIOD WAVE LENGTH ENCOUNTER FREQUENCY on the ab SESAM Program version 6 2 RESPONSE VARIABLE CONTOUR LEVELS ORDINATE VALUES AMPLITUDE PHASE AMPLITUDE REAL IMAGINARY ORDINATE UNITS DEGREES RADIANS SECOND ORDER GRAPH FIRST DIRECTION SECOND DIRECTION SUM DIFFERENCE Postresp 15 DEC 2007 5 67 scissa axis when displaying response variables and wave spec tra This will also influence the print of response variables such that the fi
172. nted Long term fatigue based on a Weibull fit of the significant responses stress ranges of the cells in a scatter diagram can also be printed The command is PRINT LONG TERM FATIGUE WEIBULL ONLY GRES1 DNV X ONLY 108000 This requires that a long term response calculation is done for the response variables in this case GRESI Postresp SESAM 3 10 15 DEC 2007 Program version 6 2 3 11 Internal Name Conventions The response variables read from the Results Interface File response spectra and short term responses gen erated by Postresp will have internal generated names or numbers The following name and number conven tions are used FORCE Transfer functions of first order wave exciting forces and moments FORCE force in x direction FORCE2 force in y direction FORCES force in z direction FORCE4 moment about x axis FORCES moment about y axis FORCE6 moment about z axis MOTION Transfer function of first order rigid body motions SURGE translation in x direction SWAY translation in y direction HEAVE translation in z direction ROLL rotation about x axis PITCH rotation about y axis YAW rotation about z axis DRIFT Transfer function of second order mean drift forces DRIFT force in x direction DRIFT2 force in y direction DRIFT3 force in z direction DRIFT4 moment about x axis DRIFTS moment about y axis DRIFT6 moment about z axis HDRFT Transfer function of horizontal second order me
173. on Name of Workability Analysis WORKABL Apply Cancel Figure C 34 DELETE SN CURVE WAVE STATISTICS WAVE SPREADING FUNCTION WAVE SPECTRUM WORKABILITY ANALYSIS SESAM Program version 6 2 C8 DISPLAY Menu 2 gt Lo sje Ei POSTRESP 6 2 04 Postresp 15 DEC 20074 C 31 Long Term Response Matrix Response Co Spectrum Response Spectrum Response Variable Sectional Force Diagram Short Term Response Speed reduction curve SN curve Specific Point Wave Spectrum Wave Spreading Function Refresh Figure C 35 DISPLAY pulldown menu File Assign Change Create Define Delete EEZZLVEP Print Run Select Set Help 2 gt Lo fes Long Term Response gt Response Variable Matrix gt Sectional Force Diagram Response Co Spectrum TENS A Response Spectrum Response Variable Sectional Force Diagram Short Term Response Speed reduction curve SN curve Specific Point Wave Spectrum Wave Spreading Function Refresh Figure C 36 DISPLAY LONG TERM RESPONSE pulldown menu Postresp SESAM C 32 15 DEC 2007 Program version 6 2 MM POSTRESP 6 2 04 File Assign Change Create Define Delete PEvEV Print Run Select Set Help 2 ele a ios Response Co Spectrum Potential Damping Response Spectrum Total Damping Response Variable Sectional Force Diagram Short Term Response Speed reduction curve SN curve Specific
174. on curve EXAMPLES ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION 180 SRI ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION 210 SRI ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION 240 SRI ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION 270 SRI ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION 300 SRI ASSIGN SPEED REDUCTION CURVE WAVE DIRECTION 330 SRI Postresp SESAM 5 8 15 DEC 2007 Program version 6 2 ASSIGN WAVE DIRECTION PROBABILITY WAVE DIRECTION PROBABILITY dir prob PURPOSE To assign a long term wave direction probability to an existing wave direction for later use in calculating long term statistics The assignment will override the previous assignment PARAMETERS dir Wave direction prob Probability of the wave direction EXAMPLES ASSIGN WAVE DIRECTION PROBABILITY 180 0 1666 ASSIGN WAVE DIRECTION PROBABILITY 210 0 1666 ASSIGN WAVE DIRECTION PROBABILITY 240 0 1666 ASSIGN WAVE DIRECTION PROBABILITY 270 0 1666 ASSIGN WAVE DIRECTION PROBABILITY 300 0 1666 ASSIGN WAVE DIRECTION PROBABILITY 330 0 1666 SESAM Program version 6 2 Postresp 15 DEC 2007 5 9 ASSIGN WAVE SPECTRUM SHAPE WAVE SPECTRUM SHAPE name PIERSON MOSKOWITZ ALL hsl JONSWAP gam sma smb hsu PART GENERAL GAMMA Isp _ nsp tzl ISSC tzu PURPOSE To assign a wave spectrum
175. ons used will be those assigned to the wave statis tics models PARAMETERS RESPONSE VARIABLE Long term response for a given response variable will be creat ed resp Name of the response variables for which the long term re sponse is to be calculated Wild card specification is available dir Main wave direction Wild card specification is available EXAMPLES CREATE LONG TERM RESPONSE RESPONSE VARIABLE ONLY AG2 ONLY 0 0 15 0 30 0 45 0 60 0 75 0 90 0 SESAM Postresp Program version 6 2 15 DEC 2007 5 31 CREATE RESPONSE CO SPECTRUM sprea RESPONSE CO SPECTRUM respl resp2 dirt spect NONE PURPOSE To create response cross spectra For 2 response variables of the same kind for each global wave direction and wave spectrum a new response cross spectrum is created The user may select several wave directions wave spectra and one wave spreading function if short crested sea is assumed The program will generate internal numbers on each response cross spectrum which will be used as refer ence later The different numbers and a descriptive text for each response cross spectrum may be achieved by using the overview alternative under the PRINT RESPONSE CO SPECTRUM command PARAMETERS resp 1 Name of the first response variable to be included in the co spectrum calculation resp2 Name of the second response variable to be included in the co spectrum calcula
176. or Background If Background is selected Pos tresp is executed without the Postresp dialogue window appearing on the screen Specify Prefix Name and status of the Database file Status of the database is either New or Old see description of the Response Postprocessing dialogue Select File name and enter name of the Command file for reading an existing journal file containing command lines input for Postresp If None default is selected Postresp will wait for input from the user Click the OK or APPLY button to start the Postresp execution The dialogue window of Postresp appears on the screen and Postresp may now be operated as described in this manual Exit Postresp and the Run a program dialogue of Manager appears A new start up of Postresp may be performed or the session closed by clicking the CANCEL button and exit the Run a program dialogue 4 2 3 Starting Postresp from Manager Command Line or Journal File Click the toggle command button and switch to the command line mode see Section 4 6 The command line area appears in the dialogue window along with a list of main commands see Figure 4 4 Enter appro priate commands by clicking in the command list or type commands directly in the command line Postresp is started by entering Run POSTRESP and Command Input File optional Postresp 4 6 15 DEC 2007 I SESAM MANAGER D5 3 04 R5Big 5
177. or a co spectrum The spectra are not named but will be identified by integer numbers A response spectrum is generally a wave spectrum multiplied by the square of the transfer function for an auto spectrum or by the cross function for a co spectrum There will be one spectrum generated for each response available main wave heading and each wave spectrum used The internal numbering conventions are given in Section 3 The response spectra are given as double amplitude response For further description of the theory please see Appendix B The printout of an auto spectrum contains the moments the response spectrum width parameter T for the response spectrum and the short term parameter while a co spectrum printout contains the covariance the correlation coefficient and the zero moments for the auto spectra of the two response variables in question Except for spectra generated by a general gamma spectrum it is possible to dump the spectrum values for a given spectrum name The response spectra may also be displayed or plotted with a maximum of 6 spectra in the same graph Response spectro for HzAVE long crested seo Resoonse Spectrum Energy density lee2ies 1 0 Angular Frequency lrod e gt MEAVE Oies0 0 FRPMII IGentical porometers 2 WEAVE Ove 45 0 FRPMIIL Deon 290 0 HEAVE Oic 90 0 FAPNII Figure 2 4 Response spectra for HEAVE motion SESAM Postresp Program version 6 2 15 DEC 2007 2 7 2 6 Short Term Response T
178. ostresp As indicated in Section B 5 this leads to a cycle rate vo zr and parameters ay r and b r of a Weibull distribution Equation B 89 that characterises an arbitrary stress cycle from the long term distribution The long term damage is then estimated not from a loop over all seastate cases as in Equation B 142 but rather as a single evaluation with these long term Weibull parameters Dic T DR K T dur DLrVL7 B 143 Postresp SESAM B 30 15 DEC 2007 Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 20074 C 1 APPENDIX C PULLDOWN MENUS AND DIALOGUE WINDOWS OF POSTRESP This appendix shows the pulldown menus of the Postresp commands and dialogue windows connected to the items in the pulldown menus When clicking an item in the pull down menus three different actions may take place 1 the command ini tiates a program execution immediately 2 the command opens a dialogue window through which user interaction may take place 3 a subcommand list pops up to the right of the command The action rules are illustrated below Action rules for items in the pulldown menu I The command button Command initiates a program execution 2 The command button Command opens a dialogue window 3 The command button Command P shows a list of subcommands to the right of the button Postresp C 2 C1 15 DEC 2007 SESAM Program version 6 2 POSTRESP dialogue window and commands NE POSTRESP 6 2 04 F
179. owing log DEFINE PRESENTATION OPTION SIMULTANEOUS BODIES SINGLE DEFINE PRESENTATION OPTION ABSCISSA AXIS PERIOD DEFINE PRESENTATION OPTION RESPONSE VAR ORDINATE VALUES AMPLITUDE DEFINE PRESENTATION OPTION RESPONSE VARIABLE ORDINATE UNITS RADIANS DEFINE PRESENTATION OPTION RESP VAR SECOND ORDER GRAPH FIRST DIRECTION DEFINE PRESENTATION OPTION RESPONSE VARIABLE CONTOUR LEVELS 1 0 1 0 0 2 Postresp SESAM 4 20 15 DEC 2007 Program version 6 2 4 6 Using Postresp in Line Mode The line mode environment in Postresp is very powerful It has many features and provides a great flexibil ity to the user This section describes the facilities one by one Even when running graphics mode the line mode environment is available through the command input line There are two modes of operation inside the line mode environment called command mode and program ming mode Command mode is the commonly used mode it is used to give commands to Postresp A new input line always starts in command mode To switch to from programming mode inside an input line type the dollar sign Programming mode is used basically to calculate numerical values These values can then be used in a com mand if desired or they can be viewed as results Programming mode is described in detail in Section 4 6 3 When moving through the commands Postresp will present a prompt possibl
180. own menu may have a submenu sliding sidewards from the parent menu To select an item in a pulldown menu click on it or drag the mouse pointer to the item and release the button Dialogue boxes Much of the user interaction will happen through dialogue boxes Those items in the pulldown menus that have three dots following the item label all open a dia logue box when selected The dialogue box is described more fully in Section 4 5 3 Print window After the first Print command has been issued a print window will pop up This is a scrollable window that contains all the output from the Print command that is di rected to the screen The window has a limited buffer so if a single print command generates excessive amounts of print some of it may disappear out ofthe top of the window The print window may be iconised separately from the main window It is possible to print inside an iconised print window It does however not pop up au tomatically from an iconised state when something is printed Postresp SESAM 4 14 15 DEC 2007 Program version 6 2 File Assign Change Create Define Delete Display Print Run Select Set Help Amplitude of Response Yor iable Wove period Il secon ab HEAVE Dir 15 aw HEA VE Dir 46 Dir 60 Dir 90 Current body is now BODY1 Closing input file POSTRESPIDEF Figure 4 8 Main window with graphics area SESAM Postresp Program version 6 2 15 DEC 2007 4 15 4 5 2 How to get help When inside a dia
181. paper while the unframed plot is somewhat smaller On the screen they will fit into the same window so the framed display will be smaller than the unframed plot The titles and company name will only appear when the frame is on Turn the drawing of a dotted grid on off in an xy plot Does not apply to pie chart plots Postresp 5 138 15 DEC 2007 EXAMPLES The following options are default when Postresp starts up with a new database 3 d DRAWING CHARACTER TYPE SOFTWARE DRAWING FONT SIZE ABSOLUTE 2 0 DRAWING FONT TYPE SIMPLE DRAWING FRAME OFF DRAWING GRID ON a d E d Lu 3 d NANA YN ti Ed Dd Dd Dd 3 3 SESAM Program version 6 2 SESAM Postresp Program version 6 2 15 DEC 2007 5 139 SET GRAPH LINE OPTIONS XAXIS ATTRIBUTES YAXIS ATTRIBUTES ZAXIS ATTRIBUTES GRAPH PURPOSE Set options that apply to graphs SUBCOMMANDS LINE OPTIONS Set options controlling how lines are drawn and marked not active in Postresp XAXIS ATTRIBUTES Set options controlling the drawing and scale of the x axis YAXIS ATTRIBUTES Set options controlling the drawing and scale of the y axis ZAXIS ATTRIBUTES Set options controlling the drawing and scale of the z axis Postresp 5 140 15 DEC 2007 SET GRAPH LINE OPTIONS BLANK END POINT DASHED DASH DOT DEFAULT DOTTED SOLID LINE TYPE line LINE OPT
182. preading function used on the scat ter diagram are to be assign on beforehand An example is given below It is assumed that a wave statistics model with the name SCAT is already cre ated in the form of a scatter diagram and that a wave spreading function named COS2 is created The work ability analysis is to be performed for the response variables HEAVE PITCH and ROLL with main wave directions 0 45 and 90 degrees The wave spectrum shape to be used is the default assignment of a Pierson Moskowitz spectrum ASSIGN WAVE ASSIGN WAVE STATISTICS 0 SCAT STATISTICS 45 SCAT SESAM Postresp Program version 6 2 15 DEC 2007 3 9 ASSIGN WAVE STATISTICS 90 SCAT ASSIGN WAVE SPREADING FUNCTION SCAT COS2 ALL Then the workability analysis named WORK can be done The allowable double amplitude response level is 1 for all three response variables CREATE WORKABILITY WORK Workability analysis HEAVE 1 PITCH 1 ROLL 1 0 45 90 3 9 Calculation of Second Order Statistics The calculation of second order response statistics is only available through the PRINT command The sta tistic calculation will be based on predefined wave spectra wave energy spreading functions and sea state duration by default 3 hours and for a given set of probability of exceedance Further input to the calculations is a selected excitation force if only second order or first order response in addition is to be included and if differe
183. put line in graphics mode but when used here the output from the operating system will appear in the terminal window from which Postresp was started 4 6 14 Appending Input Lines After receiving an input line Postresp will process the input unless told otherwise The way to suspend processing of an input line is to type a backslash as the last character in the line Postresp will then issue the append prompt gt gt An example CREATE SPECIFIC POINT SP1 Description of point SP1 gt gt 10 0 2 3 Postresp SESAM 4 30 15 DEC 2007 Program version 6 2 4 6 15 Viewing the current Status of a Command Some commands are long and it may be difficult to keep track of what has actually been given as input In other cases where commands have been inserted it is desirable to see what the current command s actually look like to Postresp For this reason the command has been introduced A few examples is the best way to show what it does DISPLAY RESPONSE VARIABLE DEFINE PRESENTATION OPTION Define Presentation Option DISPLAY RESPONSE VARIABLE DEFINE PRESENTATION OPTION Define Presentation Option ABSCISSA AXIS PERIOD Name HEAVE 4 6 16 Comments A comment may be typed anywhere in a command while in command mode not in programming mode Comments are prefixed by the percent sign Everything from the percent sign to the end of the line is treated as a comment comment need not be the first item on
184. r Matrix of Values sss eere nnne 4 17 4 5 7 Journalling from Graphics Mode eere 4 19 Using Postresp in Line Mode sse ener enne nennen inrer 4 20 4 6 1 SHOW toget helpuz zac wie Gu e s eee ie edet re eed ven Teke eter dae e dades 4 20 4 6 2 Command Input Files esses ener entente nennen 4 2 46 3 Ihebuitzin Calculator eee e em ee pe RO re D e ei ee keen 4 22 4 6 4 Accessing default Values zen m eod b E RETO RU Me D e uide 4 23 4 6 5 Abbreviation and Wildcards sess 4 24 4 6 6 Input ofa Text or Name or Numerical Value esses 4 24 4 6 7 Selecting a single Alternative from a List sess 4 25 4 6 8 Selecting several Alternatives from a List ccccccecsecsseesseeseceseeeseeeseceseceeeeeeesseesseeseens 4 25 4 6 9 Entering a Vector or Matrix of Values eene nennen 4 26 4 6 10 Setting and clearing Loops in a Command sse 4 28 4 6 11 Inserting a Command into another Command sse 4 28 4 6 12 Aborting all or parts of a Command sess eee 4 29 4 6 13 Access to the Operating system eene ener nene 4 29 4 6 14 Appending Input Lines sesesseseeseeeeeeennenne enne ener neret nnne 4 29 4 6 15 Viewing the current Status of a Command rsrernvnrenrnnvrrnnrrnrrrnvnrnnrsnvrrsvesnrsersrrnsrsnrssnnserernn 4 30 4 6 16 Comments iet ae tete teet nee ee Eee idi leds eta er uadit eed 4 30 5 COMMAND DESCRIPTI
185. range will be generated This alternative will cre ate internal names which will be prfx where prfx is the first 4 letters of the name given and js an integer number in increasing order see Section 3 3 The calculation of the spectrum will be based on a significant wave height Hs and zero upcrossing period Tz Hs 1 for Full Range calculation Significant wave height Hs Zero upcrossing wave period Tz The calculation of the spectrum will be based on the wave spectrum parameters o Postresp 5 48 alpha p frmin p frmax p freq gamma sigmaa sigmab tzmin tzmax incr SCATTER DIAGRAM SINGLE SESAM 15 DEC 2007 Program version 6 2 Slope parameter a of JONSWAP spectrum Minimum value of the peak angular frequency c for full range calculation Maximum value of the peak angular frequency c for full range calculation Peak angular frequency Op of JONSWAP spectrum Enhancement factor y of JONSWAP spectrum Default is 3 3 Left width o of JONSWAP spectrum Default is 0 07 Right width op of JONSWAP spectrum Default is 0 09 Minimum value of Tz when full range calculation Maximum value of Tz when full range calculation Increment between tzmin and tzmax Total number of generated spectra will be maximum minimum increment 1 A set of wave spectra are generated based on the Tz values with Hs values equal to 1 for the wave scatter diagram assigned to the corresponding wave spectrum
186. re given freq Selected angular frequency Postresp 5 132 15 DEC 2007 SELECT SELECT DATA SET name PURPOSE Used to select between data set or bodies PARAMETERS DATA SET Selection of data set or body in frequency domain name Name of the data set or body if multiple body solution SESAM Program version 6 2 SESAM Program version 6 2 SET SET COMPANY NAME DISPLAY DRAWING GRAPH PRINT PLOT TITLE PURPOSE 15 DEC 2007 Set options that apply generally to print and display plot Postresp 5 133 Postresp 5 134 SET COMPANY NAME COMPANY NAME name PURPOSE Set the company name for use with result presentation PARAMETERS name The name of the company NOTES SESAM Program version 6 2 The name is used at the top of a framed display plot see SET DRAWING FRAME It is not used with printed results EXAMPLES SET COMPANY NAME Det Norske Veritas Software SESAM Program version 6 2 Postresp 15 DEC 2007 5 135 SET DISPLAY ON COLOUR OFF SCREEN DISPLAY DESTINATION FILE DEVICE device WORKSTATION WINDOW _ left right bottom top PURPOSE Set options that affect the display of data PARAMETERS COLOUR DESTINATION device WORKSTATION WINDOW left Turn colour on off in the display Note that display and p
187. red to the total number of occurrences in the scatter dia gram Postresp will provide the user with a direct measure of the workability In order to offer a combined workability feature there is also a possibility to select more than one response variable For each response variable an allowable double amplitude response level must be given Using a combined option the program will calculate both the individual and the combined workability in order to present both results in a print table The combined workability may be seen as a lower envelope in the scatter diagram 2 11 Second Order Statistics The calculation of second order response statistics is only available through the PRINT command For systems modelled as second order Volterra that is by linear and quadratic transfer functions Postresp provides direct calculation of statistics of the system output Input data for the analysis are the directional wave spectrum o B the bi directional sum and difference frequency quadratic transfer functions H and the directional linear transfer function The first four statistical moments the mean standard deviation skewness and kurtosis of the system output are reported In addition extreme levels satisfying some given probability of exceedance can be reported Long crested waves are of course a special case of this general analysis The first order effects and the con tributions from the sum or difference frequencies in the secon
188. rinter depending on the com mand SET PLOT FORMAT Examples Postresp SESAM 3 2 15 DEC 2007 Program version 6 2 PRINT OVERVIEW ALL PRINT RESPONSE VARIABLE HEAVE DISPLAY RESPONSE VARIABLE PITCH 0 45 90 c CREATE wave energy spreading function if short crested sea is required Example of a spreading function named COS2 CREATE WAVE SPREADING FUNCTION COS2 Cosine power 2 COSINE POWER 2 d CREATE wave spectra for use in generating response spectra and short term response The FULL RANGE option will generate a set of wave spectra with equal H values and for a range of T values The names generated consist of the user defined prefix up to 4 letters and a sequential numbering Example given for a range from T 5 0 to T 15 0 with a step of 0 5 for a spectrum type of Pierson zmin zmax Moskowitz CREATE WAVE SPECTRUM FRPM Full range with Tz PIERSON MOSKOWITZ FULL RANGE 5 0 15 0 5 e Generate response spectra for wanted transfer functions and wave spectra These response spectra might be used in calculating short term extreme statistics The response spectra generated are numbered sequen tially Example for HEAVE PITCH 3 wave directions a wave spectrum named FRPM11 with H 1 0 and T 10 0 and short crested sea CREATE RESPONSE SPECTRUM HEAVE PITCH 0 45 90 FRPM11 COS2 f Generate short term response
189. riptive text for identification of the short term response and for informa tion of what basic variables the short term response is created from To generate a short term response the user must input the name of the response variable for which the short term response shall be created Further input is for which main wave direction and what wave spectrum type and T range the short term response is to be calculated The user also has to input whether a long crested sea or short crested sea with a given wave spreading function shall be used The program offers a wildcard alternative on each level in the command structure The user may for instance have the short term responses calculated for all response variables and all wave directions If a short crested sea 1s used and there are a large number of response variables or wave directions please be aware of the CPU consumption which may be high If the number of response variables is ny the number of wave directions mg and the number of T values kr the total number of response spectra which contrib utes to the short term responses will be Dot Rp Mwd krz Postresp SESAM 3 6 15 DEC 2007 Program version 6 2 On the other hand the number of short term responses generated 1s A stp nt Mwd Two examples are given below One with long crested sea and one with short crested sea and a wave spread ing function called COS2 The short term responses are requested for HEAVE and PIT
190. rm Response 8 Type of Long term Response Response Variable Response Variable Wave Direction SN curve Response Variable Wave Direction Cancel Figure C 8 CHANGE LONG TERM FATIGUE LONG TERM RESPONSE SESAM Postresp Program version 6 2 15 DEC 20074 C 7 ME Change Response Variable Figure C 9 CHANGE RESPONSE VARIABLE SESAM Postresp C 8 15 DEC 2007 Program version 6 2 ME Change Matrix x ME Change Specific Point Matrix Type Specific Point Name C Restoring Element ij Description X Coordinate Y Coordinate Z Coordinate Cancel Type Cosine Power Power E DK Apply Cancel Figure C 10 CHANGE MATRIX SPECIFIC POINT WAVE SPREADING FUNCTION SESAM Postresp Program version 6 2 15 DEC 20074 C 9 ME Change SN curve Figure C 11 CHANGE SN CURVE Postresp SESAM C 10 15 DEC 2007 Program version 6 2 ME Change Wave Spectrum Es ME Change Wave Spectrum Description Type JONSWAP Type Pierson Moskowitz Parameters Hs Tz Cancel Cancel Figure C 12 CHANGE WAVE SPECTRUM SESAM Postresp Program version 6 2 15 DEC 20074 C 11 lli Change Wave Spectrum x ME Change Wave Spectrum Description 2D User Specified Type User Specified Function gt lt gt lt lt c gt lt Include Exclude Overwrite Insert before Clear Help Apply Cancel Apply Cancel Figure C 13 CHANGE
191. rm calculation If the Froude number prescribed by the speed reduction curve does not exist in the result data input to POSTRESP data for this Froude number is interpolated among the given ones PARAMETERS name User given name of the speed reduction curve txt Descriptive text of the speed reduction curve Hs Significant wave height Froude Froude number EXAMPLES CREATE SPEED REDUCTION CURVE SR2 SPEED RED INCLUDE 5 0 0 2 6 0 0 18 8 0 0 16 SESAM Postresp Program version 6 2 15 DEC 2007 5 43 CREATE WAVE SPECTRUM 2D USER SPECIFIED GENERAL GAMMA ISSC JONS WAP OCHI HUBBLE PIERSON MOSKOWITZ TORSETHAUGEN USER SPECIFIED WAVE SPECTRUM name txt PURPOSE To create wave load spectra The wave load spectra is typically used for generation of response spectra or short term responses Postresp SESAM 5 44 15 DEC 2007 Program version 6 2 CREATE WAVE SPECTRUM 2D USER SPECIFIED WAVE SPECTRUM name txt 2D USER SPECIFIED wdir freq dens PURPOSE To create a general user specified directional wave spectrum where the user may give the energy density for selected wave directions and frequencies PARAMETERS name Name of the spectrum txt Descriptive text of the spectrum wdir Input wave direction freq Input angular frequency dens Specified energy density for input frequ
192. roduced in these definitions is the factor q In the work of Molin and Chen Ref 8 Naess Ref 9 and Marthinsen and Winterstein Ref 7 q is equal to 1 2 In the work of Kim and Yue Ref 6 q is equal to 1 This factor will be carried through the derivations here allowing the results to be applied to either definition of the second order transfer functions SESAM Postresp Program version 6 2 15 DEC 2007 B 23 Equation B 97 can be rewritten to make its quadratic form more obvious i t 89 i t 8 ae H Op 0 aje B 98 1 i Mz I Mz 1 X t 2 k 1 i ogt 9 i ogtt 8 ok ae H5 Op oJaje i 0 1 0 i o t 8 LAE Hy Op O aje i 0 1 0 x i t 0j E aye i Op Qjaje where the superscript denotes the complex conjugate This can be rewritten in matrix form as H H a x t AF ar Hh a i B 99 a 2 2 The a term in Equation B 99 is a vector of complex Gaussian processes in time given by i 0 t 0 aje a I B 100 i Myt Oy aye The Hermitian symmetry in the H matrix guarantees that x gt f remains a real process The a vectors can be standardized by factoring the variances of the individual processes o of Equation B 95 out and moving them into the H matrix That is define i t 0 ak z Tage B 101 and rewrite Equation B 99 as DS x t E d gt H x t z rz B 102 This results in the following de
193. rogram Limitations There are certain program limitations with respect to some of the input parameters These limitations may be listed during execution by using the PRINT LIMITATIONS command Currently the limitations are Maximum number of wave directions is 360 Maximum number of frequencies is 201 Maximum number of sections with sectional loads is 100 Maximum number of responses is 2000 Maximum number of zero upcrossing periods for short term response calculation is 25 Maximum number of zero upcrossing periods for long term response calculation is 25 Maximum number of significant wave heights for long term response calculation is 25 Maximum number of zero upcrossing periods combined with different wave shapes used in long term response calculation is 75 Maximum Number of Points forming a graph is 500 Maximum Length of Variable Name is 8 Maximum Length of User given text strings is 50 Maximum number of frequency pairs for QTFs is 50x50 All response variables read from the Results Interface File are assumed to have same and equally spaced wave directions It is required in short crested sea calculations to have the wave directions in the area from 0 degrees to 360 degrees and the sequence of the wave directions must be in increasing order If Postresp does not find a certain wave direction it will use the direction in the opposite i e or 180 degrees This is cor rect as
194. rs Postresp SESAM 4 4 15 DEC 2007 Program version 6 2 ll Response Postprocessing E dit input file Figure 4 2 Dialogue window for Postresp Database status New When Postresp has not been run before or when it is wanted to start Postresp with an empty database Old To restart Postresp with an existing model Input mode Window The only alternative available Command input file None Postresp will be started and wait for input from the user Default Manager will create a few commands to make Postresp establish a model file for the current analysis File name An existing journal file containing commands for Postresp should be selected The commandis in the file will be processed by Postresp when it is started SESAM Postresp Program version 6 2 15 DEC 2007 4 5 4 3 3 Starting Postresp from Manager with Utility Run Menu Select Run in the Utility menu of Manager The Run a program dialogue appears see Figure 4 3 E Run a program Program Executable Path Run mode Windows Database New v Command file Filename v T en omine artup Name POSTRESP ES FT Plot Edit input file iv MANAGER defaults Apply Cancel Figure 4 3 The Run a program dialogue of Manager Select POSTRESP in the Program selection box and the program executable in the Executable selec tion box if alternatives are present Specify the Run mode Alternatives are Windows
195. rsion 6 2 PRINT SHORT TERM FATIGUE SHORT TERM FATIGUE durat spec sn curve PURPOSE To calculate and print short term fatigue for several response spectra using a specified SN curve and a Rayleigh distribution function PARAMETERS durat User specified duration in seconds for which the total damage shall be estimated spec Response spectrum reference number for which the short term fatigue is to be calculated sn curve Name of the user specified SN curve EXAMPLES PRINT SHORT TERM FATIGUE 10800 123 DNV X SESAM Postresp Program version 6 2 15 DEC 2007 5 121 PRINT SHORT TERM RESPONSE SHORT TERM RESPONSE number PURPOSE To print short term response calculated for a set of Tz values PARAMETERS number Reference number of the short term response Postresp 5 122 SESAM 15 DEC 2007 Program version 6 2 PRINT SHORT TERM STATISTICS SHORT TERM STATISTICS RESPONSE LEVEL PROBABILITY OF EXCEEDANCE SEA STATE DURATION RAYLEIGH RICE level spec prob spec durat spec PURPOSE To calculate and print short term statistics for several response spectra The distribution functions available are either a Rayleigh or a Rice function The user can have the prediction after either a given response level a given probability of exceedance or for a given sea state duration PARAMETERS RAYLEIGH RICE
196. rst column written in the table will be according to chosen abscissa axis All items under this branch of the command applies to presen tation of response variables only Contour levels to be used for display of a second order response variable as a contour graph The contour levels are given as an equidistant set of values by specifying the lowest value the highest value and a step value The values will be of the form Low i Step starting from Low and not exceeding lt High gt Switch between real and imaginary or amplitude display of first order response variables This option has no effect on presenta tion of second order response variables One or several response variable amplitudes are displayed One response variable with amplitude and phase angles is dis played The real and imaginary part of one response variable is dis played in the same graph Switch between degrees or radians default as angular units when presenting rotational modes The rotational modes will be presented in print and plots in de grees The rotational modes will be presented in print and plots in ra dians This option determines how a graph is displayed as a cut in the functional presentation of a second order response variable The second order response variable is for each given set of di rections a function of two frequencies The first choice determines the cut to be shown by selecting what is to be fixed the fixed value it
197. s Postresp SESAM 4 22 15 DEC 2007 Program version 6 2 4 6 3 The built in Calculator Postresp has a fully equipped calculator that allows for on line calculation of numerical expressions The calculator has Numerical expressions using parentheses and the standard operators and exponentiation e Variables containing numerical values can be defined and reused Built in constants functions and procedures To enter programming mode use the dollar sign It must be preceded by a blank space if it is not the first character entered To leave programming mode again finish the input line or type another followed by a blank space Variables are assigned a value simply by using the syntax name expression where name is the name of the variable and expression is a numerical expression Variable names must start with a letter a z or A Z Any following character can be alphanumeric or an underscore Variables and predefined constants are used by typing their name in place of a numerical value inside a numerical expression The value of the variable or constant is substituted for the name when the value of the expression is calculated The command HELP PROGRAMMING MODE gives on line access to the information supplied here HELP PROGRAMMING MODE VARIABLES gives a list of all the variables that are currently defined HELP PROGRAMMING MODE BUILT IN gives a list of all built in constants functions and proce dures The qu
198. s Presentation Mode Presentation Mode Full Matrix C Full Matrix Single Element Frequency Cancel Figure C 46 PRINT LONG TERM FATIGUE Weibull MATRIX ADDED MASS SESAM Postresp Program version 6 2 15 DEC 20074 C 41 ME Print Matrix Potential Damping x ME Print Matrix Potential Damping El Presentation Mode Presentation Mode Full Matrix C Full Matrix C Single Element Single Element Frequency Element ij Cancel ME Print Response Co Spectrum L3 Print Response Spectrum Cross Spectrum Auto Spectrum Spectrum Statistics Dump Spectrum C Dump Spectrum Reference Number Reference Number Apply Cancel Figure C 47 PRINT MATRIX POTENTIAL DAMPING RESPONSE CO SPECTRUM RESPONSE SPECTRUM Postresp SESAM C 42 15 DEC 2007 Program version 6 2 Print Second Order Statistics Frequency ay Order First Order Included z Force Probability of Exceedance EXCITATIONFORCE 1 Las EXCITATIONFORCE 2 EXCITATIONFORCE 3 EXCITATIONFORCE 4 EXCITATIONFORCE S EXCITATIONFORCE 6 Y Wave Spectrum Include Exclude Overwrite M Insert before Clear Help Wave Spreading Main Direction Figure C 48 PRINT SECOND ORDER STATISTICS SESAM Program version 6 2 15 DEC 20074 ME Print Response Variable Order Variable Name First Direction C First Order Apply ME Print Response Variable Variable Name C Second Order Cancel ME Print Specific Point Point Name
199. s much higher than that of A RANGE OF LOWER FREQUENCY SPECTRUM i RANGE OF HIGHER FREQUENCY SPECTRUM W FREQUENCY Figure B 3 Ochi Hubble double peaks spectrum model B 1 7 Torsethaugen Spectrum The sea state is described by superposing a part according to locally wind generated sea on another part according to swell Each of the parts is described by a generalized Jonswap spectrum The generalized Jon swap spectrum S as a function of the orbital frequency has the form N o M 2 M w a B 28 St G0o e y 8 28 SESAM Postresp Program version 6 2 15 DEC 2007 B 7 where y denotes the peak enhancement factor with exponent a defined by 2 1 Aes B 29 e The parameter c is a measure of the width of the spectral peak here put equal to 0 07 if lt and 0 09 if gt is the orbital frequency of the peak related to the peak period T by w 2n T GO is a nor malizing factor for the Pierson Moskowitz form and is given by N 1 s i B 30 Nh M GO r T denotes the complete gamma function h is a factor used to fit the spectrum to a given significant wave height H In other words N 1 l S am N M o H ra eT 0 M a do B 31 I The ordinary Jonswap spectrum is obtained by putting M 4 and N 5 If in addition y 1 we have the Pier son Moskowitz PM spectrum In many descriptions of Jonswap and PM spectra H is assumed given by Phillips constant a so that h a
200. s somehow in error Postresp will give an error message and keep the start up dia logue box open for a new file specification If the file specification is correct Postresp will open the database file with extension mod and a journal file with the same prefix and name but with extension jnl It will then show some preliminary messages giving the status of some default settings and of the database These messages are shown in the next session Finally the start up dialogue box will disappear SESAM Postresp Program version 6 2 15 DEC 2007 4 3 4 2 1 Starting Postresp from Manager with Result Menu In Manager the Result menu will be available when a Results Interface File exits for the current project In the Result menu Postresp is available under the selection Response POSTRESP see Figure 4 1 If the Result menu is not available greyed out click Option Superelement to specify the actual superele ment or Option Enable All Menus 1 SESAM MANAGER 5 3 02 WadamRun2 121 Wave load workshop PIE Me Poma Model Lood Aniyss ES pebea m General XTRACT Response POSTRESP Sectional Results CUTRES Plate Code Check PLATEWORK Shell fatigue STOFAT Postprocessing ADVANCE Xtract Results Edit Program Files Figure 4 1 Main dialogue of Manager and the Result menu The Response Postprocessing dialogue for Postresp see Figure 4 2 has the following paramete
201. s standard motion combinations for displacement velocity or acceleration or by special combinations where the user is free to add transfer functions with scaling fac tors in any way The transfer functions may be printed displayed saved in a plot file or plotted on an on line printer Amplitude of Response Vor voble ADL UDS 0 1 2 1 4 Angulor Frequency rods Figure 2 1 Response variable for HEAVE motion Postresp SESAM 2 2 15 DEC 2007 Program version 6 2 If there are sectional forces given with the section numbers increasing continuously from 1 to n Postresp also offers a sectional force diagram for a user specified degree of freedom 2 2 Wave Spectra The wave spectra are different types of wave load spectra There are three different standard wave spectra and one user defined spectrum The wave spectra are PIERSON MOSKOWITZ with input of the significant wave height H and the zero up crossing period T ISSC with input of the significant wave height H and the mean peri od Ti i JONSWAP with input of either the significant wave height Hs and the zero upcrossing period T or a and the peak angular frequency op and the parameters y o and op TORSETHAUGEN with input of the significant wave height H and the peak period Tp Ref 11 OCHI HUBBLE with input of the significant wave height H and the peak period Tp one pair for contribution from swell and one for wind gen erated sea Note that the applicat
202. segment SESAM Program version 6 2 Second segment continues with m1 2 m0 1 Second segment continues with m1 m0 Second segment is horizontal Second segment is arbitrary Slope of second segment Third segment continues with m2 ml Third segment is horizontal Log cycles to failure at end second segment Slope of third segment SESAM Postresp Program version 6 2 15 DEC 2007 5 41 CREATE SPECIFIC POINT SPECIFIC POINT name txt x coor y coor z coor PURPOSE To create specific points of which the user can generate absolute or relative displacement velocity or accel eration combinations PARAMETERS name User given name of the point txt Descriptive text of the point X coor X coordinate in the global coordinate system y coor Y coordinate in the global coordinate system Z COOr Z coordinate in the global coordinate system origin in the free surface EXAMPLES CREATE SPECIFIC POINT PF Point for air gap computation 27 0 12 5 Postresp SESAM 5 42 15 DEC 2007 Program version 6 2 CREATE SPEED REDUCTION CURVE SPEED REDUCTION CURVE name tx Hs Froude PURPOSE A speed reduction curve gives what Froude number speed to use in a given sea state as a function of sig nificant wave height This is used when the contribution from each cell sea state in a scatter diagram is calculated in a long te
203. self is entered into the DIS PLAY command The possibilities are Fix a frequency value in the first direction Fix a frequency value in the second direction Fix the sum of the frequencies Fix the difference of the frequencies Postresp SESAM 5 68 15 DEC 2007 Program version 6 2 The second choice determines the value to place on the abscissa axis This is a function of the choice of cut in the function When a first or second direction value is fixed the abscissa will be the other direction second or first When the sum of the frequencies is fixed the abscissa can be either the FIRST DIRECTION the SECOND DIRECTION or the DIFFERENCE When the difference of the frequencies is fixed the abscissa can be either the FIRST DIRECTION the SECOND DIREC TION or the SUM SESAM Program version 6 2 15 DEC 2007 DEFINE RETURN PERIOD RETURN PERIOD period PURPOSE To define return periods used in the long term response calculations PARAMETERS period Return period in years Postresp 5 69 Postresp SESAM 5 70 15 DEC 2007 Program version 6 2 DEFINE SPEED REDUCTION SPEED REDUCTION ON OFF PURPOSE This is used to specify that speed reduction will be taken into account in long term statistics and long term fatigue calculations When speed reduction is ON the Froude number choice will be absent in the DIS PLAY LONG TERM RESPONSE command since the results then
204. sp Program version 6 2 15 DEC 2007 3 7 ASSIGN WAVE DIRECTION PROBABILITY 0 0 125 ASSIGN WAVE DIRECTION PROBABILITY 45 0 25 ASSIGN WAVE DIRECTION PROBABILITY 90 0 25 ASSIGN WAVE DIRECTION PROBABILITY 135 0 25 ASSIGN WAVE DIRECTION PROBABILITY 180 0 125 ASSIGN WAVE STATISTICS 0 NOR1 ASSIGN WAVE STATISTICS 45 NORLI ASSIGN WAVE STATISTICS 90 NOR1 ASSIGN WAVE STATISTICS 135 NOR1 ASSIGN WAVE STATISTICS 180 NOR1 ASSIGN WAVE SPREADING FUNCTION NOR1 COS2 ALL CREATE LONG TERM RESPONSE HEAVE PITCH 3 6 Calculation of Short Term Statistics The short term statistics calculation is only available through the PRINT command The statistic calculation will be performed on created response spectra addressed through their reference number The short term statistics is given as the single amplitude response The input to the calculations are the short term distribution type Rayleigh or Rice response level probabil ity of exceedance or sea state duration and the spectrum requested Three examples are given below One with response level as input one with probability as input and one with sea state duration as input The response spectra used are related to HEAVE motion RINT SHORT TERM STATISTICS RAYLEIGH ESPONSE LEVEL 0 750 0 900 1 2 3 RINT SHORT TERM STATISTICS RAYLEIGH ROBABILITY OF EXCEEDANCE 0 003 0 001 1 2 3 RINT
205. sponse SESAM Postresp Program version 6 2 15 DEC 2007 2 9 Long term response for HEAVE Long Term Response 5 Reuponse 2 4 8 Li Log Qt Proo Reeponss Yor cote HEAVE O1r0 0 HEANE 0ir845 0 O HEAVE Oires0 0 9 M AYE ALL Inc Figure 2 6 Long term response for HEAVE motion 2 9 Equation of Motion The response variables for the motion of the structure are obtained by solving the equation of motion In Postresp the response variables may be user defined or they are read from a Results Interface File The coefficients in the equation of motion may also be read from a Results Interface File and the restoring and body mass coefficients may be changed by the CHANGE MATRIX command Solving the equation of motion internally in Postresp the user has the opportunity to vary coefficients like body mass or flotation area while analysing the response of the structure It is also possible to interpolate the coefficients between the frequencies for which they are given on the Results Interface File The advantage of doing this is that the coefficient matrices are normally linear func tions of the frequencies and that a lot more information is thereby obtained compared to interpolating the response variables themselves For example interpolation of the coefficients between frequencies on each side of the peak frequency may give a response value very close to the correct peak value even if the response values at
206. t Weight for each elementary wave direction relative to the main wave direction Postresp SESAM 5 26 15 DEC 2007 Program version 6 2 CHANGE WAVE STATISTICS txt tv p tv h0 hc h0 gamma WAVE STATISTICS name ntz distr nsd at bt cond nhs hsmax ah bh steep PURPOSE To change wave statistics based on Nordenstrem s theory The program will verify whether the given name is used on a scatter diagram or a Nordenstrom model PARAMETERS name Name of the wave statistics txt Descriptive text for the model tv Visual wave period Tv p tv Probability that Tv falls within the interval represented by the class midpoint ho Weibull parameter for the distribution function describing the probability that the visual wave height does not exceed Hv hc h0 Weibull parameter gamma Weibull parameter ntz Number of zero upcrossing periods which will be used in the long term calculation distr Distribution function of the zero upcrossing periods Tz Either NORMAL or LOG NOR MAL nsd Number of standard deviations by which the range of Tz is extended at either end at Parameter defining the relationship between zero upcrossing period Tz and visual wave pe riod Tv bt Parameter defining the relationship between Tz and Tv cond Conditional coefficient of variation of Tz nhs Number of significant wave heights to be used in the calculation of the long term response hsmax Maximum va
207. te a set of stress transfer functions which can be read into Postresp through the Hydrodynamic Results Interface File and used in the short or long term stochastic fatigue calculations In the short term fatigue calculation the fatigue damage can be obtained for a short term duration of a given sea state The short term fatigue assumes Rayleigh distribution of the stress ranges and takes response spec tra S N curves and durations as input The expected value for failure is then calculated and printed Long term fatigue calculation can be calculated either based directly on a scatter diagram where Rayleigh distributions are assumed for each cell or based on a Weibull fit from a long term response calculation of the significant responses stress ranges of the cells Speed reduction can be taken into account in long term fatigue calculations Both the short term and long term fatigue calculations are based on the assumption that a single slope or bi linear S N curve is used Further description is given in Appendix B THEORY AND FORMULATION Chapter B 7 Frequency Domain Fatigue SESAM Postresp Program version 6 2 15 DEC 2007 3 1 3 USER S GUIDE TO POSTRESP Chapter 3 is divided into three parts Sections 3 1 gives a short description of the general usage of Postresp Sections 3 1 through 3 9 describe different modes of operating Postresp such as generating response var iables response spectra short and long term responses workab
208. tension JNL containing the Postresp input commands On a Unix system the user may also create a similar command input file e g POSTRESP_IN JNL and then issue the command below in order to execute Postresp as a background process postresp sta new interface line POSTRESP IN JNL POSTRESP LOG amp Alternatively if the three first lines of the input file myinput inp contains the following input POSTRESP NEW followed by ordinary line commands then the following commands will start Postresp and process the input On Windows prompt postresp 1 lt myinput inp On Unix prompt postresp 1 lt myinput inp gt myinput log 8 The header and messages generated by Postresp are sent to the logfile 4 2 7 Files and Data Safety Postresp uses the following files Database The database file is a direct access file that is used to keep the model and analysis results It has the extension mod Journal The journal file is used to keep a log of most of the commands that are accepted during a Postresp session If an existing OLD database is opened the journal will be appended to the corresponding old journal file if this exists The journal file has the extension jnl Postresp SESAM 4 10 15 DEC 2007 Program version 6 2 Results Interface The Sesam Hydrodynamic Results Interface File is normally used for transferring data from hydrodynamic analysis programs Doing this the file will consist of tra
209. text of the response variable dir Global wave direction freq Angular frequency real Real part of the response variable imag Imaginary part of the response variable MIRROR Mirroring of selected response variables The mirror plane is the XZ plane Modes in the mirror plane such as Surge Heave and Pitch are symmetric Modes normal to the mirror plane such as Sway Roll and Yaw are anti symmetric First order motions and excitation forces and sectional loads can be mirrored respt Selected names of response variables to be mirrored EXAMPLES CHANGE RESPONSE VARIABLE STRESS STRESS 90 0 INCLUDE 203 250 1 101 3 CHANGE RESPONSE VARIABLE MIRROR HEAVE Postresp 5 18 15 DEC 2007 CHANGE SN CURVE SN CURVE name USER txt m0 s0 logNO DEFAULT TAIL ALIGNED WITH FIRST HORISONTAL TAIL ARBITRARY TAIL ml ALIGNED WITH SECOND HORISONTAL TAIL logN1 ARBITRARY TAIL logN1 m2 PURPOSE To change the properties of a SN curve PARAMETERS name USER txt m0 s0 log NO DEFAULT TAIL ALIGNED WITH FIRST HORISONTAL TAIL ARBITRARY TAIL ml ALIGNED WITH SECOND HORISONTAL TAIL logN1 m2 Name of the SN curve Only user defined option available Descriptive text of the SN curve Slope of first segment Stress level at end first segment Log cycles to failure at end first segment
210. the frequencies on each side of the peak are both much lower than the peak value Postresp SESAM 2 10 15 DEC 2007 Program version 6 2 Since generation of coefficients like added mass and damping for the equation of motion is quite CPU con suming these features may save some CPU time and serve as a powerful tool for analysing hydrodynamic data 2 10 Workability Analysis Postresp offers the possibility to make workability analysis for a given response variable wave direction and allowable double amplitude response level As for the calculation of long term responses a scatter dia gram has to be assigned This can be done by creating a new diagram interactively or by reading from an external file given on Sesam Interface File format or by selecting one of the predefined diagrams Note that only a scatter diagram may be used as the wave statistics model not the Nordenstr m model The procedure for performing the workability analysis up time is similar to the long term response For each cell a significant response 4 alo 1s calculated and scaled with the actual significant value H This value is compared with the user specified allowable double amplitude response level If the significant response level is below the allowable value the number of occurrences or probability of this sea state is stored Doing this for all sea states cells and adding all occurrences which were below the allowable level the proportion of this sum compa
211. tion when short crest ed sea NONE Long crested sea no wave spreading function EXAMPLES CREATE RESPONSE SPECTRUM ONLY HEAVE ONLY 90 0 ONLY PMSINGLE NONE SESAM Postresp Program version 6 2 15 DEC 2007 5 33 CREATE RESPONSE VARIABLE COMBINED MOTION FIRST DERIVATED RESPONSE VARIABLE name text GENERAL COMBINATION SECOND DERIVATED USER SPECIFIED PURPOSE To create internal response variables either as combinations of existing response variables or as sole user specified response variables Postresp 5 34 SESAM 15 DEC 2007 Program version 6 2 CREATE RESPONSE VARIABLE COMBINED MOTION RESPONSE VARIABLE name txt COMBINED MOTION point DISPLACEMENT RELATIVE resp VELOCITY mode ABSOLUTE ACCELERATION PURPOSE To create a combination of global motion responses The combination will be a standard motion combina tion of a given point consisting of either displacement velocity or acceleration absolute or relative to sea surface elevation PARAMETERS name txt point resp DISPLACEMENT VELOCITY ACCELERATION RELATIVE ABSOLUTE mode EXAMPLES Name of the response variable Descriptive text of the response variable Point of which the combination is to be defined Name of the global motion response variable to be included in the combinatio
212. to the print file Direct print to the screen Set the print file name and prefix The total file name is the con catenation of lt prefix gt and lt name gt and the extension lis Set the number of lines per screen page Set the orientation of the print in the print file Will use up to 132 characters horizontally Will use at most 80 characters horizontally The SCREEN HEIGHT is by default set to 24 lines This number is reset every time Postresp starts up even if it had been set to another value in a previous run When running in graphics mode the print in the print window may look cleaner if the SCREEN HEIGHT is set quite large e g to 100 The DESTINATION is reset to SCREEN every time Postresp starts up even if it had been set to another value in a previous run SESAM Postresp Program version 6 2 15 DEC 2007 5 147 The CSV FILE option gives the same print as the FILE destination option but a semicolon is inserted as delimiter between each column in the print table The print will contain the print introduction page and page break inclusive table nomenclature at top of each print table It is therefore recommended to print each wanted data table to separate files and remove additional information above the table prior to e g importing the table data into Microsoft Excel The file name will get the extension csv This print option sets the maximum number of lines for each print table to 100000 Use this option o
213. ts on the Postresp data base and which one of these that is current It also prints the data card read from the Results Interface File if any SESAM Program version 6 2 15 DEC 2007 PRINT LIMITATIONS LIMITATIONS PURPOSE This command gives a list of the current limitations in Postresp Postresp 5 109 Postresp 5 110 SESAM 15 DEC 2007 Program version 6 2 PRINT LONG TERM FATIGUE LONG TERM FATIGUE resp durat SUMMARY FULL WEIBULL FIT resp sn curve durat PURPOSE To print long term fatigue for a selected response variable directly 1 e using a Rayleigh distribution or based on an already existing long term response calculation based on a Weibull fit PARAMETERS WEIBULL FIT resp durat sn curve FULL SUMMARY EXAMPLES Long term fatigue will be calculated based on an existing long term response Response variable s for which the long term fatigue is printed User specified duration in seconds for which the total damage shall be estimated Name of the SN curve to be used Full print of results including partial results for each cell in the scatter diagrams Print summary of results Partial results for each cell in the scatter diagrams are not printed PRINT LONG TERM FATIGUE WEIBULL GRES1 GRES2 GRES3 DNV X 15 5e7 3 1e8 15 5e8 SESAM Postresp Program version 6 2 15 DEC 2007 5 111 PRINT
214. ude this is R t Eq H cos ot gt B 60 The phase angle of the response with respect to the incoming wave and amplitude is then given by I H he pRy2 1 2 dis H QH T B 61 where H and H are the real and imaginary parts of the transfer function respectively The response top then occurs At 6 before the wave crest at origin phase lead B3 2 Standard Combinations Transfer functions may be combined to describe other responses The complex transfer functions of the basic motions in the six degrees of freedom for example may be combined to describe other motions in the x y and z directions at arbitrary locations on the structure Some examples that illustrate the combination process are provided below Postresp SESAM B 16 15 DEC 2007 Program version 6 2 The absolute motion in the z direction is given by Haime Hnreave XH piten t VA roll B 62 The relative motion in the z direction is given by Hrm H Hotels B 63 The absolute motion in the y direction is given by Himo Lagt Xy EB B 64 The absolute motion in the x direction is given by Hae 7 Hsurge V TE B 65 Transfer functions for the velocity Hy and the acceleration Hj may be derived from the motion transfer functions Hj using the relationships H ioHy B 66 H o Hu B 67 B3 3 Special Combinations Special combinations of transfer functions Hyq may also be derived i n Hsc d gt C H i i 1 Il s B 68 wh
215. ve height of the total spectrum whereas Tp is taken as the period of the primary peak In other words the total doubly peaked spectrum Saps is constructed as SESAM Postresp Program version 6 2 15 DEC 2007 B 13 B 54 Saps 0 s o Hs Hs Ip TP N N M M 7 7 sl v Hs Hs Tp TP NN MS M y 57 B2 LONG TERM DESCRIPTION OF SEA Long term statistics are associated with non stationary processes occurring over periods of months and years whereas short term statistics covered in the previous section relate to stationary processes in periods lasting only a few hours In forming a long term statistical description of the seas a suitable statistical model providing a joint probability distribution of wave height and wave period is required B2 1 Statistical Model The statistical model of the wave data provides the joint probability of occurrence f H 7 of significant wave height and the mean zero up crossing period In Postresp this joint probability is formulated as the product of the probability of wave period and the probability of wave height within that wave period Ref L KAT ATA TT B 55 where the parameters of the wave height distribution for one specific value of wave period are determined independently of the parameters for other wave periods conditional distribution B2 2 Distribution of Wave Height A three parameter Weibull distribution may be employed to describe the distribution of wave hei
216. which the long term fatigue is to be calculated Wild card specification is available dir Main wave direction Wild card specification is available sn curve Name of the SN curve to be used EXAMPLES CHANGE LONG TERM FATIGUE ONLY STRESS ONLY 0 0 30 60 90 0 120 0 150 180 0 210 240 0 270 0 300 0 330 DNVC II SESAM Program version 6 2 Postresp 15 DEC 2007 5 15 CHANGE LONG TERM RESPONSE LONG TERM RESPONSE RESPONSE VARIABLE resp dir SLAMMING point slpre thrvel dirt PURPOSE To change long term responses given for either a selected set of response variables or in a slamming station specified point PARAMETERS RESPONSE VARIABLE Long term response for a given response variable will be creat ed SLAMMING Long term slamming calculation is requested resp Name of the response variables for which the long term re sponse is to be calculated Wild card specification is available dir Main wave direction Wild card specification is available point Name of the specific point where long term slamming is calcu lated The z coordinate for this point must be given in the glo bal coordinate systems i e positive upwards and will act as draft for the vessel at the given point s pre Slamming pressure coefficient in given point thrvel Threshold of relative velocity between wave and vessel Slam ming is defined to occur if the relative velo
217. y followed by a default in The main command level is signified by the prompt No default is presented here The main commands are ASSIGN CHANGE CREATE etc These are described in Chapter 5 When moving inside a command the prompt will change and a default may be pre sented Different items on the command line are separated by blank spaces except if it is text that is protected inside quotes In special cases the blank space may be left out Such cases are documented in the sections below Postresp does not require line breaks anywhere except for a few cases in programming mode these are described in Section 4 6 3 Thus several commands can be typed into the same command input line This is however not recommended as it easy to lose oversight in such a case In the following input typed by the user is shown in bold while prompts given by Postresp are shown as ordinary text 4 6 1 How to get help Context sensitive help is available in command mode at any time using any of these methods Type to get a brief description of what Postresp is expecting right now Type text during a selection between alternatives to see all the alternatives that match text text may contain wildcards or be an abbreviation Type to get a more descriptive help text showing how to proceed There is also a HELP menu under the main menu giving on line access to the items that are described here Inside programming mode the question mark may

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