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User Guide - ATA Engineering

1. 5 2 1 2 Title Card for Analysis Set All Analysis Types smsmssssrsssserersrrserersrrnrr ara 6 2 1 3 Load Set Excitation ssssssssersssssseorssseneorrrsrnr ner rsrn ans eme e sensns 8 24 4 Enforced Motions ccc eR ERR pA RE Elea pee oder ten AERA ERNA 9 2 1 5 Coupled Damping Matrix cece cece ee eee eee mmn 11 2 16 Residual Modes iege RAA ee Ka sara AA NA ed ae KA 12 2 1 7 Modal Effective Mass Output sssssrrrsseserrrssrsrrrrsrrrrrrrrrr mee 14 2 2 Supported Nastran Entities sssmmisssseersrsssserrrrrrsererrrrrererrrrr mem emen nens 15 2 3 Supported Nastran Versions and Solution Types smtosssssersrssrsersrssrrrrrrrrr nere rr rna 17 3 Vibrata User Guide re a a A E RAE RET aE FU a AAPEEE EEE Aa Ua 18 3 1 Event Manager Interactive User Interface sssmssssrsssserrrrrrrrrrerrrrrr rer rrrr reser rar na 18 3 1 1 General Characteristics of the User Interface smusssssrsrsssrererrsrrererrr rara 18 331 2 EVENE EISE REGIONS iin entente e ertt Dh s KANE Re iat 18 3 1 3 FEM Selection Region sssomserassenerrtarsenssrrrsen ants rsrn ann memes 18 344 Solver TaB nen tiders nr elek e es peeled ed epp edu laa Pod e de e aud 18 31 5 ExcitatlonsS Tabs uiii irren T tase E n esa E A x ERO Nt ee anaes 18 3 1 6 Modal Settings Tab cece eee eee emen 18 3 1 7 Defining Modal Damping ssssssssses mmn 18 3 1 8 Output Request Tab ssssssssssssssssesn eene sehen hene 18 3 1 9 Contour Outp
2. Treat excitation as rigid body Node Dir 6000 1 6000 2 6000 Scale Type Function Name GroundTransport Figure 4 42 Select enforced motion select Z translation and then bring up the Function Manager 30 Using the Viscous Damping Schedule on the Modal Damping Definition dialog assign 1 damping for modes up to 100Hz and 2 for modes above 100Hz 60 Vibrata Documentation Example Problems solver Exckations Modal Settings Output Modal Damping 96 Frequency Modal Viscous Damping Summary User Matrix User Matrix Mode Frequency Schedule Diagonal Off Diagonal Ratio Diagonal Off Diagonal Ratio No Hz 35 x Mean Max 1 Mean Max 1 8 3581 100 2 9 5070 100 3 15 6635 100 4 20 2297 100 E 20 3059 100 6 20 5483 100 7 21 4998 100 8 217011 100 Frequency Hz Damping 96 100 100 100 01 2 00 Figure 4 43 Assign damping via the schedule export the schedule to a text file for later use 31 The Instrumentation Package contains scientific instruments that may be damaged by excessive vibration and we want to be sure the satellite bus will not be overstressed Click the Contour button on the Output tab to open the Contour Requests dialog In its Output Intervals panel make sure that only RMS output is checked Request Von Mises stress SVMS for the BUS SHELLS group click Apply then turn on the Select nodal variables toggle and request total translational acceleration
3. gt RFM Reaction Forces and Moments RFINV Reaction Force Invaria UTMAG Translation Magnitude C v Velocities VTMAG Translational Velocity Magnitude C Interactive 4 C AR Rotational Accelerations ATMAG Translational Acceleration Magnitude MI mi Tatal Nirnlaramante Plot XY Plot Contour Return output in the displacement coordinate system X Results Node Selection Node Groups Figure 4 23 Request X acceleration response plots for all three nodes 12 Click Solve on the Output tab to solve for the requested data 13 Plot the results 9 Select Plot XY on the Output tab 10 On the UIPLOT dialog select All and then Plot Notice the dynamic amplification and phase change around each natural frequency Also note how by right clicking on the legend you can reposition and reorient it 41 Vibrata Documentation Example Problems fe MeO Aanu Uem PLOT Hele Select Figure 4 24 Plot the acceleration response of all DOF 4 2 3 Frequency Response of a Frame In this example you will run two events with the frame model one with a constant input and one with a non constant input to see how the different inputs affect the response 14 In Femap import the frame model frameO01 modes dat Figure 4 3 and its results frameO01 modes op2 Save the Femap model file as frame modfem 15 In the Event Manager start a new modal frequency event and select fra
4. go de Scratch S gt vraTest gt frame 4 Organize New folder Sr Favorites Name Date modified Type i frame FreqRsp Const vra xyout 8 28 2013 5 43 PM VRA_XYOUT File 53 Libraries L frame FreqRsp Var vra xyout 8 29 2013 9 06 AM VRA XYOUT File JE Computer 4 m p Made Hir Ate Capen File name frame FreqRsp Constvra xyout Vibrata XYOUT vra xyout RN Templo as Tospiuno LE Figure 4 36 Load results from the constant amplitude event into the output plotter 24 Plot and compare the results For example Figure 4 37 shows the total X displacement of node 15 from both events Although the amplitudes differ due to the different excitation levels the phase changes are identical for both curves because these depend only on the modal frequencies Use the Plot Options menu to change the data displayed in the legend inset Use the right mouse menu in the plot window to show the X axis with a log scale 54 Vibrata Documentation Example Problems ge zm f eomm Dutmusiepet Une PU ULOT hd b Y cule LT Gnd Teg Ld Label Legend RTT i 1 Piet Bye AOT V Ces phase Fae Piot Options Satistics Legend Unis ON UPLOT Help AYN y Unk Prot Can v Display legend om plot venus Link All Aves Default Lord Template Uridine Al Aves v IDueei Copy to new fiquem Plots per Page 6 IDLines Grouping Ref Res Coords Sid
5. 82 With the Point Force Excitations dialog set per Figure 4 112 use the t 69 button to bring up the Function Manager If you have already run the examples in Section 4 2 3 open the frame excitations fcn file used there if that file does not currently exist you will create it when you have finished defining the current function Define a triangular pulse as shown in Figure 4 114 Note that you enter the pulse parameters Start Width Amplitude End not the specific X and Y data points when you click Apply the Function Manager automatically makes the appropriate data point entries This force roughly models a hammer blow to the structure When all the definitions are complete on the New Function dialog click the Create button Store the function to frame excitations fcn Figure 4 115 Click Done on the Function Manager main dialog to return to Point Force Excitations dialog and click OK there to finalize the excitations Figure 4 116 125 Vibrata Documentation Example Problems Functions Menege vreModwTrensientExact Name FunctionType d ool Co Function Type purse X Spacing Start End Increment Points Interpolation Type Linkin Y Axis Type Force Pulse Shape Triangle Amplitude Figure 4 114 Define a unit force triangular pulse function 126 Vibrata Documentation Example Problems Choose a destination file S wraTest frame frame_e
6. SK S DISP EMENT PLOT ALL STRESS SORT1 PLOT FIBER CORNER ALL FORCE SORT1 PLOT CORNER ALL MEFFMASS NOPRINT PLOT GRID 6000 MEFFM YES METHOD 1 Sx 5 Figure 2 10 Request for modal effective mass output relative to a specific node Vibrata supports Nastran models that have discarded modes using the MEFFMASS THRESH parameter 2 2 Supported Nastran Entities Since Femap imports the modes results directly Vibrata can support nearly everything that Femap imports The same goes for results in local coordinate systems Vibrata does not perform any coordinate system transformations in the solvers so the output results are available in whatever coordinate system s Femap used when importing Please refer to the Femap documentation for more details One exception to the above statements has to do with the enforced motion results Since Femap does not import the NX Nastran RA datablocks Vibrata reads them directly from the OP2 file and places them into the Femap MODFEM file This means that enforced motion excitations are always defined in the drive node s displacement coordinate system Table 2 1 summarizes the NX Nastran enforced motion datablocks that Vibrata supports Table 2 1 Supported NX Nastran enforced motion datablocks Vibrata Documentation Preparing Nastran Input files Result Type Erb Data Type Constraint Mode RADCONS Displacement Constrai
7. Bug Fixes Fix TIER 1187 1211 1231 1232 1235 1237 1238 1239 1243 1244 1269 1284 1321 1342 1345 1349 1388 1389 Fix coordinate system issues with base excitation and update the user manual to clarify coordinate systems in Vibrata CBEAM and CBEND elements supported for base excitation Other minor bug fixes and enhancements Version 1 0 6 Enhancements Allow user to select whether to use Fast RMS in the Random solver Bug Fixes Fix TIER 885 1187 1216 Other minor bug fixes and enhancements Version 1 0 5 Bug Fixes Fix TIER 1189 Fix bug where RMS von Mises stresses were not calculated correctly when using the regular solver for random analysis This was introduced in 1 0 4 and did not affect Fast RMS results Other minor bug fixes and enhancements Version 1 0 4 Enhancements Significant performance improvement to von Mises stress calculation for random analysis Add toggle to point force excitation inputs to specify that the inputs are defined in the nodal displacement coordinate system Add toggle to Node XY quantity requests to specify that the outputs should be returned in the nodal displacement coordinate system rather than the basic coordinate system Bug Fixes Fix TIER 1032 1099 Fix bug where solid element RMS stresses were not calculated correctly when using the Fast RMS solver for random analysis Fix bug in statistics display in XY plotting when switching units Other m
8. Select Nodes for Excitation 4225 Remove Exclude 4494 to by 1 2 RCS THRUSTER LOAD NODES 4 m Select s elf correlated mecum Apply Close Figure 4 93 Use the Point Force dialog to assign a Z direction force to each thruster node 70 In the Function Manager you will create a time function to excite the ISat transient event If you have already run the random examples in Section 4 3 1 open the Sat excitations fcn file used there if that file does not currently exist you will create it when you have finished defining the function for the current example As shown in Figure 4 94 create a new transient function set its Y axis to Force give it uneven X spacing and assign it the X and Y values shown The pulses have unit amplitude this will let us size the RCS thrusters just by scaling the excitations Remember to give the function a recognizable name Click Create to store the function to an fcn file Figure 4 95 Click Done on the Function Manager to return this function to the Point Force dialog Assign it a scale factor of 20 and then click OK on the Point Force dialog to create the excitations Figure 4 96 107 Vibrata Documentation Example Problems r Functions nag hranate l Name FunctionType OrdNumDataType Number lem4 X Spacing Start 08 Increment 0 ae 1 Function Sets Points HS 1 l B i ji 1 D 05 1 15 2 r Tr
9. Diagonal Off Diagonal Ratio Diagonal Off Diagonal Ratio No 96 Mean Max 96 Mean Max a 4 5 6 7 8 9 10 11 ay w Viscous Damping Schedule Frequency Hz Damping 96 Cc I e Modal Damping Matrix Fle Name Figure 4 97 Use the damping schedule to assign 196 damping to all flexible modes 72 0n the Output tab create a contour request for translational displacements and accelerations UT and AT for all nodes in the model Request output at 0 05 second intervals to span the defined start and end times of the event Figure 4 98 for a 4 0 second time span this will produce 81 output time steps Note that Vibrata will change your definition to its preferred form inset when you click Apply or OK this 110 Vibrata Documentation Example Problems will produce the same results as settings you entered Click OK to create the request Stress Contour m Node XY Recovery Intervals Elem XY lt none Trans_Contours 4 E U Nodal Displacements IV UT Translations UR Rotations V Nodal Velocities 4 A Nodal Accelerations V AT Translational Accelerations F AR Rotational Accelerations TU Total Nodal Displacement Contour Groups ALL NODES AND ELEMS T Select all nodes Shell Beam Stress Recovery Point none v Output Intervals Contour Interval Set Trans Contours z SS x Set interval selection intent Or set specific output times First output
10. New response spectrum event with absolute value summation 91 Assign an enforced motion function to direction 1 snssssssssrsrssrrrrrerrrr rer rer rar 92 Define a Response Spectrum velocity fUNCtION cc ce eee eect sees eeeeeeeeeenees 93 Store the new function in the frame excitations file ccccc cece eens eee eeaees 94 The excitation uses the basic coordinate system cece cece cece eee estas eee ed 94 Damping is not needed and the damping dialog button is disabled 95 Request translational displacements and accelerations at all nodes 96 Copy the event and change the summation method to SRSS 97 Copy again to create a third event using NRL summation sssssss 98 Copy again to create a fourth event using NRC summation ssss 99 Select Criteria and Deformed views from Femap s Post toolbar 99 Displacements for a absolute value and b SRSS methogds 100 Displacements for a NRL and b NRC methods cccceseeeeeeeeeeeeenes 101 Accelerations for a absolute value and b SRSS methods 102 Accelerations for a NRL and b NRC methods sese 103 Transient event setup for deployed ISat model sssesseseesss 105 Nodes for RCS thruster loads sssmssererrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr menm 106 Use the Point
11. Output Set RMS AnSet 2 Nodal Contour T2 Translation Figure 4 56 RMS acceleration contours for the instrumentation package 4 point base uncorrelated 43 Compare the Y acceleration response PSD from this case to the one from the rigid base event On the Output tab click the PLOT XY button to bring up the UI PLOT dialog It will show the functions for the current event which is the 4 point model with uncorrelated inputs Use the File Load File menu to make the results of the rigid base event available Figure 4 57 Plot the TATy function from both events Figure 4 58 Again they are clearly quite different 73 Vibrata Documentation Example Problems File Plot Options Statistics Legend Plot tod File Puick Filter Load Workspace Show All Save File Save Workspace Lon Node 557 int Group port int Group Done int Group pwum rurce siement x KS gt vraTest p Het m 4s Search Sot 8 d e Date modified i d Vibrata XYOUT vra xyout v File name Sat Rad RanGround vra xyout Figure 4 57 Add the rigid base results to the those available for plotting 74 Vibrata Documentation Example Problems NE RMS 0 786305 i RMS 1 1348 Total Acceleration Node 5577 TAT y q grid none basic Total Acceleration Node 5577 TAT y 9 grid none basic Figure 4 58 The Y acceleration responses for the two events are very d
12. SwraTestISatMSat sm Launch 4pt modfem ISat 4pt RanGround Corr Modal Random SAvraTestNISatNSat sm Launch 4pt modfem f F Modal Random S vraTestISatiISat_sm_Launch_Rgd modfem gt J u amp xportus Figure 4 67 Copy the original rigid base event the new one will use FastRMS contour calculations 48 On the Excitations tab turn on the Use FastRMS toggle Figure 4 68 That is the only change needed for the new event Solver Excitations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name 1 Accel Motion 6000 disp 3 1 0 GroundTransport Figure 4 68 Turn on the Use FastRMS toggle on the Excitations tab 49 Go to the Output tab and click Solve The FastRMS approach has no effect on computing response PSDs so we need only look at the contour results Figure 4 69 Visually they are indistinguishable from the results of the standard computations Figure 4 46 Figure 4 47 although interrogation will show slight numerical differences 84 Vibrata Documentation Example Problems Output Set RMS AnSet 3 Nodal Contour T2 Translation Figure 4 69 The FastRMS contours are visually identical to those from the original event 4 3 6 Deactivate Modes with Negligible Modal Effective Mass Another way to speed up your analyses is by deactivating excluding from the dynamic solution modes that will not be excited by the environment you are analyzing For enforced motion excitations but not f
13. TAT Total Translational Accelerations TATx v TATy 4X TATZ TAR Total Rotational Accelerations TATMAJG Total Translational Acceleration Magnitude Use nodal displacement coordinate system Node Selection Nodes E Node Groups Sinis Figure 4 48 Request Y and Z direction total accelerations for node 5577 66 Vibrata Documentation Example Problems Solver Exctabons Modal Settings Label BUS SHELLS Hem Contour Group Contour Group INST PIG FEM Node Power Spectral Density Figure 4 49 Node 5577 total Y acceleration in g Hz units rigid base 35 It is also important that we not exceed allowable loads in the launcher adapter legs Request axial force responses for the elements in group LAUNCHER ADAPTER FEM Figure 4 50 Solve and plot Figure 4 51 The RMS values along with other statistics about the functions can be displayed using the UIPLOT dialog s Statistics Legend menu Note that element 5632 has the largest RMS value 67 Vibrata Documentation Example Problems Stress AR Recovery All Rand Contours none Rand Contours Contour EINV Strain Invariants SSR Shell Stress Resultants E BFM Beam Forces and SFM Spring Blement Forces and Moments CCN Corm Caran Tesi reer weer ur To IP BOOM STUB FEM IP BOOM A4 FEM IP BOOM A3 FEM IP BOOM A2 FEM IP BOOM A1 FEM Ll She
14. as highlighted in Figure 2 6 This is the same alter used to enable load set excitation paragraph 2 1 3 The alter does not cause Nastran to compute complex modes It uses the undamped mode shapes to compute Burl B where B is the physical viscous damping matrix and Byy is the nModes x nModes modal viscous damping matrix It will also write the modal structural damping matrix K4yy i e the imaginary part of the modal stiffness matrix if you have defined any material damping Of course if your model does not include any damping elements or materials with damping specified there will be no Buy or K444 matrix to write The matrices are stored in the OP2 file in datablocks BHH and K4HH Do not use the datablocks called RADAMPZ and RADAMPG they do not contain the data that Vibrata requires Vibrata Documentation Preparing Nastran Input files INCLUDE c apps Vibrata vibrata nx7 Additional param for coupled damping matrices PARAM RSOPT 1 Figure 2 6 Include the Vibrata DMAP alter to get coupled modal damping matrices 2 1 6 Residual Modes Vibrata does not support mode acceleration data recovery Therefore if you require static corrections for your modal dynamic analyses you must tell Nastran to compute and store residual vectors When you have applied forces the most effective approach is to use residual modes in conjunction with load set excitation This means you need to define actual forces even if
15. process Vibrata therefore expects results generated by Nastran s modal analysis solution sequence SOL 103 The current version of Vibrata does not support upstream data recovery for superelements Vibrata Documentation Vibrata User Guide 3 VIBRATA USER GUIDE 3 1 Event Manager Interactive User Interface 3 1 1 General Characteristics of the User Interface 3 1 2 Event List Region 3 1 3 FEM Selection Region 3 1 4 Solver Tab 3 1 5 Excitations Tab 3 1 6 Modal Settings Tab 3 1 7 Defining Modal Damping 3 1 8 Output Request Tab 3 1 9 Contour Output Requests 3 2 Event Manager Batch Solution Mode 3 2 1 Batch Processing with MATLAB Scripts 3 8 Function Manager 3 3 4 Functions Region 3 3 2 Function Sets Region 3 3 3 Plot Region 3 3 4 Math Region 3 3 5 Hints for Creating Complex Functions 3 4 3 5 3 5 1 3 5 2 3 5 3 3 5 4 3 6 3 6 1 Vibrata Documentation Vibrata User Guide XY Plot Results Display Contour Results Display Viewing Transient Analysis Results Viewing Frequency Response Results Viewing Random Analysis Results Viewing Response Spectrum Results Event Definition File EVT Event File Conventions Event Summary Section Excitation Section Modal Settings Section Input Checksum Output Request Section Reusing EVT Files Vibrata Documentation Example Problems 4 EXAMPLE PROBLEMS T
16. they are unit forces in the Nastran deck and compute the generalized force matrix for them as shown in Figure 2 7 The only change from Figure 2 3 is the addition of the PARAM RESVEC card Vibrata Documentation Preparing Nastran Input files INCLUDE c apps Vibrata vibrata nx7 LOADSET 101 Additional params for Vibrata load set excitation PARAM RSOPT 1 PARAM OGEOM YES PARAM RESVEC YES LOADSET ID from LOADSET card in case control Set ID for FORCEi PLOADi etc cards not shown LSEQ 101 1 1 LSEQ 101 2 2 LSEQ 101 3 3 Figure 2 7 Add a PARAM RESVEC card to get residual modes for applied forces You can get residual modes for unit forces at designated DOF using USET U6 cards as shown in Figure 2 8 but these forces will not appear in the generalized force matrix and so cannot be used as a load set excitation 13 Vibrata Documentation Preparing Nastran Input files PARAM RESVEC YES DOF for unit loads for residual modes USET U6 3693 12 3968 12 4243 USET U6 4518 12 Figure 2 8 You can get residual modes by defining a U6 USET without any actual loads If you want residual modes for enforced motion excitation you will need a RESVINER card instead of RESVEC This will create residual modes for unit accelerations of the model in all six directions The required cards are shown in Figure 2 9 The only change from Figure 2 4 is the addition of the PARAM RESVINER card Additional
17. 0 00 Select Modes Effective mass threshold f 1 Effective mass directions 82 2934 87 7532 89 8059 92 6065 a E Ex UE LA Figure 4 71 Select modes below 0 196 modal effective mass for all translations 52 With the low mass modes selected click the Active button in the Set Mode Status panel to deactivate the selected modes Figure 4 72 This leaves only 46 of the 167 modes active so the solver will compute responses at many fewer frequencies Note however that we have deactivated less than 196 of the effective mass for any of the translations 86 Vibrata Documentation Example Problems Frequency Modal Damping 96 Translational Modal Effective Mass 96 Mode Hz Viscous Structural X Y Z 165 395 1011 2 00 0 00 0 00 0 00 0 00 166 395 3294 2 00 0 00 0 00 0 00 0 00 397 2370 2 00 0 00 0 00 0 00 Frequency Modal Damping 96 Hz Viscous Structural Figure 4 72 All but 46 of the 167 modes are turned off but 98 of the effective mass remains 53 Solve the event Here again the contour results Figure 4 73 are visually indistinguishable from those of the original event Figure 4 46 Figure 4 47 The XY Plot results however do show some differences We deactivated all the modes from 240 Hz to 400 Hz so neither the Y acceleration response PSD Figure 4 74 nor the axial force response PSD Figure 4 75 has any dynamic content in that range while the origi
18. Node 5577 TAT y g grid none basic Frequency Hz Figure 4 65 The correlated 4 point results match the rigid base results for Node 5577 Y acceleration 82 Vibrata Documentation Example Problems p Power Spectral Dersty RMS 79 9979 RMS 106 126 RMS 79 9979 on Force b yz React rapp t t T 1 Frequency Hz Figure 4 66 The correlated 4 point results also match the rigid base results for launcher leg forces 4 3 5 RMS Contours using FastRMS The I Sat model is small by today s standards and the frequency range under study is not very broad so the RMS contour calculations in the examples above do not take very long More realistic analyses where the model may have more than 500 000 elements and the frequency range of interest may be up to 2000 Hz can take many hours using standard approaches to computing RMS values Vibrata has an alternative method that is many times faster and when used properly only slightly less accurate reference 3 The I Sat model with rigid base is a good candidate for this approach 47 1n the Event Manager copy the original rigid base event from 4 3 2 using the Copy button and then assign a new name to the new event Figure 4 67 83 Vibrata Documentation Example Problems File Functions Events ISat_Rqd_RanGround Modal Random S wraTest ISat Sat_sm_Launch_Rad modfem ISat_4pt_RanGround_Uncor Modal Random
19. Problems Figure 4 5 ISat model in launch configuration with single central connection to launcher 24 Vibrata Documentation Example Problems Figure 4 6 I Sat model in deployed configuration 4 1 5 Preparing the Models for Vibrata To use the models described in the previous section copy the contents of the Vibrata examples folder to your own local directory and thereafter work only with these local copies You will note that we have included a results file Nastran Output2 containing the normal modes solution for each model You are welcome to use these instead of solving the models yourself or you may run the models and use the provided Output2 files for comparison to your own results Either way it is instructive to examine the input files to see how they satisfy the requirements described in Section 2 1 Using your own normal modes results files or those provided import the bulk data and results into Femap as shown in Figure 4 7 and Figure 4 8 Where the example folder includes a Femap neutral file with the same name as the dat and op2 files import that into Femap as well as shown in Figure 4 9 Finally save the model as a Femap MODFEM file You may wish to adjust the view settings in Femap at this point For example in the figures showing the frame and ISat models Figure 4 3 through Figure 4 6 we set the background color to solid white set the color of all labels and post processing titles to black had Fema
20. TAT for the INST PKG FEM group Figure 4 44 Click Done Back on 61 Vibrata Documentation Example Problems the Output tab click the Solve button Even with Fast RMS turned off the solution does not take long T Solver Excitations Modal Settings Output Stress Contour CO Intervals t X Output Variables Select nodal variables TV Total Nodal Velocities TA Total Nodal Accelerations RFM Reaction Forces and Moments __ S Stress in Shell Solid Elements 4 ONS yarian Y SVMS von Mises Stress o fal o Requests il SMXP Max Principal E interactive pa abana senda LAUNCHER ADAPTER FEM a ALL_BEAMS Plot XY Output Groups ALL SHELLS Plot Contour Contour Groups BUS SHELLS gt X Results BUS SHELLS RCS_PANELS ALL RCS PANEL SHELLS BEAMS FOR FORCE Shell Beam Stress Recovery Point Al Output Intervals Output Variables Contour Interval Set Rand contours lod F TU Total Nodal Displacements zh Eo ar or i 5 TV Total Nodal Velocities ers Frequencies 4 JA Total NodaLA ation Start 1 V TAT Translational Accelerations End 1 E L TAR Rotational Accelerations P __ RFM Reaction Forces and Moments a S Stress in Shell Solid Elements Al Solver Frequencies z SINV Stress Invariants frequencies between modes Select quantities to store C
21. and export capabilities used by Vibrata Femap and MATLAB however are not included with Vibrata you must obtain them separately from Siemens Product Lifecycle Management Software http siemens com plm femap and The MathWorks Inc http www mathworks com respectively 1 3 Files Model information and results are stored in four main files 1 Femap Model file modfem The finite element model FEM and its modal results reside in a Femap model file Vibrata writes its contour results into that same file 2 Function file fcn Forcing functions reside in a Function file which is a MATLAB file with a specific format created and managed by IMAT 3 XY plot results file vra xyout The XY plot results functions of time or frequency are stored in a MATLAB mat formatted file whose format is understood by Vibrata s plotting and function management tools 4 Event Definition file evt All of the data that define a dynamic event including excitations modal damping parameters requests for specific physical responses which solver to use and the names of the referenced fcn MODFEM and vra xyout Vibrata Documentation Overview files are stored in Vibrata s Event Definition or EVT file This is a text file which means that you can edit it for re use 1 4 Note on the Global Coordinate System This manual like Femap s documentation uses the term global coordinate system interchangeably with basic coord
22. being excited Solver Exctations Modal Settings Output Type Item Label Scale Factor Function Name 1 Veloc Rsp Spec i LO Rsp Spec Base Lateral Assign Forcing Functions to Valid DOF Treat excitation as rigid body Scale Type Function Name Veloc Rsp Spec Base Lateral Figure 4 80 The excitation uses the basic coordinate system 59 No damping is needed for response spectrum analysis as the damping level is already accounted for in the response spectrum function In fact you cannot even open the damping dialog Figure 4 81 94 Vibrata Documentation Example Problems Exckations Modal Settings Output Frequency Modal Damping 36 Translational Modal Effect L Hz Viscous Structural X Y a 1 0160 0 00 0 00 89 07 3 1440 0 00 0 00 8 50 5 4281 0 00 0 00 2 03 1 4140 0 00 0 00 0 40 gi l Al Active Rigid lt Mass 11 1395 0 00 0 00 0 00 j 4 J J 15 4939 0 00 0 00 0 00 None Inactive Residual gt Mass 15 5820 0 00 0 00 0 00 Set Mode Status 31 4804 0 00 0 00 0 00 Active Rigid Residual 35 6709 0 00 0 00 0 00 35 9794 0 00 0 00 0 00 100 00 Select Modes Effective mass threshold 1 0 Effective mass directions x Yz z 1 2 3 E 5 6 7 8 9 Plot Mode Shapes US Ex WE 5 m e Figure 4 81 Damping is not needed and the damping dialog button is disabled 60 Go to the Output tab Only contour output is available for response spectrum an
23. direction at all four base nodes 39 Note that 0 phase CSD functions have been defined automatically to correlate these excitations Ordinarily that is exactly what we want but here we want to compare correlated and uncorrelated results and we also want to illustrate how to use the CSD definition dialog Therefore delete these CSD functions Figure 4 54 We will recreate them manually for the event in Section 4 3 4 Scale Factor Function Name 10 GroundTransport 1 0 GroundTransport 10 GroundTransport 1 0 GroundTransport deg D deg Figure 4 54 Delete the automatic CSD entries 71 Vibrata Documentation Example Problems 40 Go to the Modal Settings tab and verify that the modes still have damping per the damping schedule 41 All other settings from the rigid base model may be left as they are Go to the Output tab and click Solve 42 When the solver finishes examine the RMS von Mises stresses in the bus Figure 4 55 and the RMS accelerations in the instrument package Figure 4 56 as before The color bars in these figures are set to the same levels as in Figure 4 46 and Figure 4 47 respectively The results are very different EE _ 2 a p we fly SS ee Output Set RMS AnSet 2 Elemerital Contour Plate Top von Mises Stress Figure 4 55 RMS von Mises stress in satellite bus shell elements 4 point base uncorrelated 72 Vibrata Documentation Example Problems
24. frame modfem Evert Details FEM Name Mode Set FEM Unts OOO S vraTest frame frame modfem 2D FRAME FOR BASE EXCITATIONS Inch Pound f Solver Exckations Modal Settings Output Solver Analysis Type Modal Response Spectrum Data for Response Spectrum Analysis Variables for Custom Solvers Name Figure 4 83 Copy the event and change the summation method to SRSS 62 Copy the first event again Change the summation method to NRL and set the Closely spaced mode factor to 1 1 Figure 4 84 From Figure 4 81 you can see that the frequencies of modes 6 and 7 and modes 9 and 10 are within 1096 of each other so they will be considered closely spaced Solve the event 97 Vibrata Documentation Example Problems File Functions Help Everts Name Type FEM Name New Frame RSpec Abs Modal Respons SNvraTestMrameMrame modfem Frame RSpec SRSS Modal Respons S vraTest frame frame modfem pr Modal Respons S vraTest frame frame modfem Fear RSpec Natit Mods Resp AA amet 4 HL gt _ Export Event Details FEM Name Mode Set FEM Units 8 Select S vraTest frame frame modfem 2D FRAME FOR BASE EXCITATIONS Inch Poundf v l FEM Solver Exckations Modal Settings Output Solver Analysis Type Modal Response Spectrum Data for Response Spectrum Analysis Variables for Custom Solvers Name Value Figure 4 84 Copy again to create a third event
25. green when the solver has finished and its results are available Figure 4 17 Plot the results by clicking the Plot XY button Solver Excitations Modal Settings Output Output Stress Contour Item Variables Recovery Intervals e rem Figure 4 17 Results are available for requests in green text Display them 3 In the UIPLOT dialog select both functions and click Plot to display the results Figure 4 18 Notice the dynamic amplification and phase change of the responses at the natural frequency 35 Vibrata Documentation Example Problems nos noes fd Oe eap VO UO Function List jut Fe Figure 4 18 Select and plot both requested acceleration responses at once 4 2 2 2DOF Frequency Response 7 You will now perform a frequency response analysis on the 2 DOF model Import the Nastran model 2dof_modes_base dat Figure 4 2 and its results 2dof modes base op2 into Femap and save as 2dof modfem 8 Create a frequency response event with this model Always define a useful recognizable name for the event Change the number of points in the range and near modes on the Solver tab as in Figure 4 19 This will refine the discretization in the XY plot In real models with perhaps hundreds of modes this will be far more refinement than you will actually want Five points on either side of each mode will be plenty and you may want only two points in the range 4 Set the number of points in the ra
26. in Figure 2 4 enables enforced motion in all three translations at four nodes For frequency response random and transient analyses all twelve of these DOF will appear in the enforced motion definition dialog paragraph 3 1 5 4 and you can apply independent excitations to all of them Response spectrum analysis however is based on modal effective masses rather than constraint modes so its motion is in the basic coordinate system relative to the single point at which the modal effective mass was calculated see Section 2 1 7 The deck shown in Figure 2 4 does not require a DMAP alter nor therefore a DMAP license If you have a DMAP license and prefer to keep your decks as consistent as possible for Vibrata analyses you can use the vibrata nx7 alter mentioned in paragraph 2 1 3 as shown in Figure 2 5 In that case you can use the Femap standard PARAM POST 1 card and leave out the PARAM OUGCORD card Otherwise the decks are identical Vibrata Documentation Preparing Nastran Input files INCLUDE c apps Vibrata vibrata nx7 Additional modified params for Vibrata enforced motion PARAM RSOPT 1 PARAM RSCON YES DOF available for enforced motion USET U2 44 123 USET U2 49 123 Figure 2 5 Alternate deck for enforced motion using DMAP alter 2 1 5 Coupled Damping Matrix NX Nastran will write the full coupled modal damping matrix to the OP2 file if you include the PARAM RSOPT card and the Vibrata DMAP alter
27. modified params for Vibrata enforced motion PARAM POST 2 PARAM OUGCORD GLOBAL PARAM RSOPT 1 PARAM RSCON YES PARAM RESVINER YES DOF available for enforced motion USET U2 44 123 USET U2 49 123 Figure 2 9 Add PARAM RESVINER card to get residual modes for enforced motion 2 1 7 Modal Effective Mass Output Modal effective mass information is required for response spectrum analyses NX Nastran will generate it automatically when you set up to recover the enforced motion data Section 2 1 4 but that may not be exactly what you want If you simply take those defaults the Vibrata Documentation Preparing Nastran Input files effective mass will be computed relative to the origin of the basic coordinate system While that will make no difference to the translational mass it will affect the rotational mass and that may be important if you mean to excite rotations in a response spectrum analysis In that case you may need to specify the node about which you want the rotational masses calculated which will then be the rotational center of your response spectrum excitation This can be done by including a MEFFMASS case control card as in the highlighted statement in Figure 2 10 Modal effective mass is generally not required for analyses that do not use enforced motions but you are welcome to request it if you want to see this data on the Modal Settings tab SE CONTROL Free Modes Small ECHO NONE
28. output sets with many different types of data Vibrata must identify and process the specific output sets that contain normal modes results and it relies on two things to do this First it must find an analysis set whose analysis type is set to Normal Modes Eigenvalue Second it must identify the output sets that contain the mode shape results for that analysis which it does by looking for the name of the normal modes analysis set at the end of the Notes entry for each output set Those output sets that contain the Normal Modes analysis set name in their notes are processed all others are ignored It is easily possible to load a valid FE model and its results into Femap without creating an analysis set at all but Vibrata will not be able to process those results if you do It is also easily possible to load a valid model and results in such a way that even when an analysis set is created its name does not appear in its output sets notes Fortunately it is also easy to make all of this work properly All that is necessary is to put a TITLE card in the case control section of your Nastran deck before you solve it as shown in Figure 2 1 If you add the TITLE card after you solve the title will not be stored in the Nastran output file Even though Femap will create the required analysis set when you import the deck that name will not appear in the output sets created so Vibrata will not recognize them Vibrata Documentation Preparing Nas
29. requirements on your Nastran decks Section 2 1 defines the Case Control Parameter and other bulk data definitions you must include in your decks so that Vibrata can use those results Following that Section 2 2 defines the entities and data that Vibrata will process and Section 2 3 defines the Nastran versions and solution types that Vibrata supports 2 1 NX Nastran Cards for Specific Vibrata Options This section defines the executive control case control parameter and other bulk data cards you must include in your NX Nastran decks to generate the data Vibrata needs in order to perform certain types of analysis The following topics are covered 2 1 1 General Requirements for Physical Response Recovery 2 1 2 Title Card for Analysis Set All Analysis Types 2 1 3 Load Set Excitation 2 1 4 Enforced Motion 2 1 5 Coupled Damping Matrix 2 1 6 Residual Modes 2 1 7 Modal Effective Mass Output The referenced paragraphs show the actual bulk data file entries not the details of how to make Femap write those entries into the decks 2 1 4 General Requirements for Physical Response Recovery Since Vibrata uses a modal post processing approach it needs mode shape data to process As a result Vibrata expects results generated by Nastran s normal modes analysis solution sequence SOL 103 SEMODES In addition you must request output as part of the modes solution for any result types you will want Vibrata to produce For example if
30. the original function and click Copy Store the new function to a new function file in the frame folder call it frame_excitations fcn Select the new function and click the Edit button On the Edit Function dialog change the second X value from 30 to 40 and click Save Figure 4 28 45 Vibrata Documentation Example Problems r Functions Plot 1 Somoe Fies Manage IvraModaFrequencyinto Ca Cee Co le Name FunctionType OrdNumDataTyj e 1 Consi 10g tto20Hr Frequency Response Function Acceleration Math X Spacing Even Uneven Editing Keys Delete Delete Row at Cursor j Insert Insert Row at Cursor r Function Sets End Append Row to End Figure 4 28 Change the copied function to have a range from 1 to 40 Hz 13 With the new function still selected click the Attributes button to open the Edit Function Attributes dialog change the interpolation method to LogLog and its name to Const 10g 1to40Hz Figure 4 29 Click Done to close the dialog and save the changes 46 Vibrata Documentation Example Problems r Functions Source Fies Manage IvraModsiFrequencytiio je Name FunctionType OrdNumDataTyfel f Const 109 tto20Hr Frequency Response Function Acceleration a Function List Edit Attributes Name IDLine1 Figure 4 29 Edit the new function s name and make it
31. time 1 Times and any two of Last output time Output interval 05 Total outputs Select quantities to store V Responses at each time Max Figure 4 98 Request displacement and acceleration contours for all nodes at 0 05 second intervals 111 Vibrata Documentation Example Problems 73 On the Output tab again click Solve to compute and store the requested contours Figure 4 99 When the solver finishes click Plot Contour to view the results in Femap You can simply double click in Femap s graphics window to start the animation You can also do any of the usual post processing operations such as showing contours of total acceleration on a deformed mesh for a specific time step as in Figure 4 100 Solver Excitations Modal Settings Output Output Stress Contour Node XY Item Label Variables Recovery Intervals Elem XY Contour Group ALL NODES AND ELEMS UT AT none Trans Contour Interactive Figure 4 99 Solve for the requested contours and then plot them 112 Vibrata Documentation Example Problems 5304 8412 7783 5857 Output Set Time 14 0651 ArSet amp Defommedl4 224 UTMAG Vector magnitude Dupiscemert Nodal Contour ATMAG Vector magnitude Acceleration BR Figure 4 100 Contours of acceleration on deformed mesh for output frame 14 74 Create another contour request This time ask for von Mises stress in the RCS mounting panels but re
32. use log log interpolation 14 With the Function Manager still open create a new acceleration function that is not constant Use the values shown in Figure 4 30 Be sure to name it as shown and set its interpolation method to LogLog We will use this function in the second part of this example 47 Vibrata Documentation Example Problems r Functions Source Fies vwraModafFrequency o v je Nome FunctionType OrdNumDataTypo New 1 Const 10g tto20Hz Frequency Response Function Acceleration el Attributes Plot a C C Increment 0 1 Points 5 10 10 10 Frequency Function Attributes 4 Name Var 1to3g 1to40Hz Interpolation Type LogLog Y Axis Type Acceleration C Figure 4 30 Make the function uneven and give it non constant amplitude 15 Select the constant forcing function for the first event Your Excitations tab should look like Figure 4 31 Note that the excitation because it is an enforced motion is taken to be in the driven node s displacement coordinate system 48 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name Point Force Accel Motion 2 disp 1 10 Const 10g 1to40Hz Enforced Motion Delete Figure 4 31 Excitations tab with resulting enforced motion def
33. you plan to ask Vibrata to compute dynamic stress responses or bar beam or spring force responses Vibrata Documentation Preparing Nastran Input files then you must request output to the OP2 file for them as part of your SOL 103 analysis Of course Vibrata can only recover physical responses for those nodes or elements that were included in your output requests Thus if your DISPLACEMENT PLOT output request specifies a subset of the nodes in your model rather than ALL Vibrata will only be able to compute dynamic displacements velocities and accelerations for the nodes in the specified subset This also has implications for applying point force excitations in your dynamic analyses Your normal modes analysis must request displacement output for every node to which you intend to apply a point force if the modal displacements are not present Vibrata will not be able to transform the forces into the modal domain 2 1 2 Title Card for Analysis Set All Analysis Types In order for Vibrata to identify the normal modes results for your model you must have a TITLE card in your Nastran deck at the time you solve it If you create your FE model and analysis cases in Femap the requirements defined in this section will essentially be met automatically If you create your models outside of Femap you should read this section carefully Femap allows you to import results from many different analysis runs into a single MODFEM file thus creating
34. 1 Excitations tab with resulting enforced motion definition ssse 49 Figure 4 32 Apply 2 damping to all modes via damping schedule then set mode 1 COLD EU 50 Figure 4 33 Request both flexible and total nodal X translation plots ssssssssrssssrerrrssrner erna 51 Figure 4 34 Use the Copy button to create a new event from an existing one 52 Figure 4 35 For the new copied event delete the old excitation and create a new jT 53 Figure 4 36 Load results from the constant amplitude event into the output plotter 54 Figure 4 37 Compare the responses of the top corner node for the two inputs 55 Figure 4 38 Access Function Manager directly from Event Manager menu 56 Figure 4 39 Create the acceleration PSD that will be used to excite the ISat 57 Figure 4 40 Create and save the function and finish by clicking Done 58 Figure 4 41 Create a new random analysis event ssssssrserrrssrrsrrrrrsrrerrrrrrs rss rr sr rr sr rr rr ers sa 59 Figure 4 42 Select enforced motion select Z translation and then bring up the FUNCTION Manager aeeti race esprit yk e a aa cles Le TY bee eters 60 Figure 4 43 Assign damping via the schedule export the schedule to a text file for EU LIE C M I RE 61 Figure 4 44 Request SVMS for the BUS SHELLS and TAT for the INST PKG FEM on
35. 5 4 3 2 ISat with Rigid BaSe esee ceni use puer eret x Ede cie 58 4 3 3 ISat with Uncorrelated Input at Each Adapter Leg ss 69 4 3 4 ISat with Correlated Inputs cece cece eee eee eee mmn 75 4 3 5 RMS Contours using FastRMS ssessssss mne 83 4 3 6 Deactivate Modes with Negligible Modal Effective Mass 85 4 4 Response Spectrum Analysis sssssssssssssssss enm 90 4 5 Transient Analysis s oe Ie ee trek unto ht d enter Hafa AE eese didis 104 4 5 1 ISat Model with RCS Thruster Firing cceeeeeeee eee eee eee eee r rna na 104 4 5 2 Frame Model Transient Animation sssmrsrsrssrsrrrrsrrsrrrrrrr eens eect rer rr rn rna 121 b Creating Custom SolVers occ 3 e Rt t eee sins xchat poe ae ek 132 bd he Solvet FIG o dion oe te ve ot EG lese nix 132 52 The Solverlnfo File dte Ye E Ra nne dae RE TR RK KRA NANA 132 5 3 The Custom Solver Folder sssssssssssss mmm 132 6 Vibrata MATLAB API For Custom SOIVErIS smssssssrersrrsrrerrrrrrrrrrrrrr er rrr mene 133 63 Directory Structure usc tee dedecus tet eee ane bathed aa UE bain e ee 133 6 2 Function Naming Convention sssssssssss me meme nenne 133 6 3 Utility Classeszcu o ee er RUE na EE ene t Ua RHET RASAR deen ERES 133 6 3 1 vraParam Vibrata Parameter Class s esses 133 6 3 2 VraReqmap Vibrata Request Mapping Class sssmresssssrrersrssrrrerrrr
36. 7 5 1 Static and Dynamic Uncertainty Factors 7 6 Enforced Motion Excitation 7 6 1 Seismic Mass Alternative 7 7 Residual Vectors 7 8 Response Spectrum Analysis 7 8 1 Absolute Summation ABS 7 8 2 Square Root Sum Square Summation SRSS 7 8 3 Naval Research Lab summation NRL 7 8 4 Nuclear Regulatory Commission Rule NRC 134 Vibrata Documentation Installation 8 LNSTALLATION Vibrata uses a client server licensing scheme You must therefore install and configure the Sentinel RMS license server Section 8 2 below separately from Vibrata itself Section 8 3 If you have other ATA software the license server is already installed and you will only need to obtain a specific license file for Vibrata to make it run 8 1 Platform Requirements Vibrata supports 32 bit and 64 bit Windows platforms any platforms supported by both Femap and MATLAB will be supported by Vibrata Vibrata requires MATLAB 2011b or later and requires Femap v11 0 x or 11 1 x to run Vibrata is compatible with all versions of Siemens NX Nastran and with MSC Nastran v2001 or later 8 2 Installing the License Server Sentinel RMS is a robust commercial client server based licensing system from SafeNet that can serve multiple licenses for multiple software products simultaneously The server typically resides on a central computer while client software such as Vibrata resides on computers that will be utilizing the software
37. Force dialog to assign a Z direction force to each thruster TO Cl S ennen at Rr E 107 Thruster force transient for I Sat maneuver stusssrrerrrrrrrrrrrrrrrrrrrrrrr nn 108 Save the ISat thruster forcing function to a file ssnmsssseserssrsrrersrrrrrrrrr rreren 108 Scale the function by 20 and then create the final excitations 109 Use the damping schedule to assign 196 damping to all flexible modes 110 Request displacement and acceleration contours for all nodes at 0 05 SECON INTERV GIS 25 2 dust estensione s n KR BR AEAEE deiode d ea alsa es Beats 111 Solve for the requested contours and then plot them ssssssse 112 Contours of acceleration on deformed mesh for output frame 14 113 Request peak values of von Mises stress in the RCS mounting panels 114 Select the RCS Panels contour request and plot its results 115 Peak von Mises stress contours in RCS panels ssrorcsssserersrssererrrrrrrrrrrnrrrr ra 115 Von Mises results with only the RCS panels group displayed 116 Select the BUS SHELLS contour request and plot its results 117 Von Mises results with only the BUS SHELLS group displayed 117 Request beam forces in elements that attach appendages to bus 119 Solve the new Element XY requests and plot them seceeeee eee ea es 120 Forces in IP boom connector note ef
38. R card to get residual modes for enforced motion 14 Request for modal effective mass output relative to a specific node 15 Single DOF spring mass model srsserersssserersrrerrerrrrrrrrrrrrrr rr rss rr rr KKR KAR RK KRKA na 20 Two DOF spring mass model seseesseresssrserererrrererrrrrrrerrr rare r rr rr RK RK KR emere 21 Two dimensional frame model missrrrerrsrrsrrsrrrrrsrrrrrrerrrrr rr rr eee mene ns 22 ISat model in launch configuration with four separate attachment points 23 ISat model in launch configuration with single central connection to launcher ee eon Rt IEEE 24 ISat model in deployed configuration sssssssssererssrsrrerrrrrrr rss rr rr rr rr m 25 Read the bulk data into Femap using the Import Analysis Model menu DICKS a dean 26 Read the modes results into Femap using the I mport Analysis Results MENU PICKS ccu ee SSR bode FR ix Ru i E UR REDE aa tS 27 Define groups in Femap by importing a neutral file when available 28 Create a new frequency response event and select the FEM on which to DSC CP sed d ucc ML UE 29 Create a new enforced motion excitation ssssssrerssssrrersrrrrrrrrrrrre re rr rr nere rerna na 30 Use the Function Manager to create an acceleration function 31 Save excitation function to new function file cc ccc eec cece eeeeeaeeeeeeeeeeanes 32 Assign 2 596 modal viscous damping to the mode
39. The client computer may or may not be the same as the license server It can also be on a different software platform than the client Sentinel RMS installation is straightforward Detailed installation instructions are shipped with the Sentinel RMS package available from ATA s website at http www ata e com software rmsserver This document highlights the basics of the installation process 8 2 1 Installing Sentinel RMS On Windows the Sentinel RMS package is an InstallShield application As such it must be installed by someone with administrator privileges ATA recommends that the default selections be used during the installation 8 2 8 Environment Variable All Sentinel RMS clients need a way to determine where the server is running By default the client will scan the subnet your client system is connected to and will identify any Sentinel RMS servers running on your subnet It will then contact each until the license request is satisfied or it has run out of servers You can control the order in which the 135 Vibrata Documentation Installation servers are contacted through an environment variable called LSHOST Set the environment variable to the hostname of the server separated by a colon The server name must be prepended by the name no net For example set it to no net serverl server2 where server1 is the name of the first license server server2 is the name of the second license server and so on Separa
40. Vibrata To install Vibrata run Vibrata_v107_Setup exe Vibrata will install itself into the C Apps Vibrata_v1 0 directory by default 8 4 Configuring Vibrata The default configuration that installs with Vibrata should be sufficient for most people so you should not have to do any additional configuration However if you have a non 136 Vibrata Documentation Installation standard environment or wish to fine tune how Vibrata works you may need to configure it All possible changes will be made in the Vibrata launch script 8 4 1 Vibrata Launch Script The Vibrata launch script is located in the top level directory of your Vibrata installation It also supports several command line arguments To see what arguments it supports type vibrata help in a Command Prompt Windows The Vibrata launch script performs several operations First it sets several environment variables that Vibrata needs These are described in Table 8 1 Finally it will launch the Event Manager which will launch Femap and MATLAB The VIBRATA_ROOT variable in the launch script must NOT be modified unless you are sure you know what you are doing Table 8 1 describes the environment variables that you may need to configure Table 8 1 Vibrata environment variables and their meanings Environment Variable Description Defines the Vibrata installation location Do not modify MIBRATASROOT this variable unless you know what you are doing Directo
41. a requires geometry specifically the GEOM4 datablock in the OP2 file so that it can determine the U2 DOF when it first sets up the model The PARAM OGEOM YES statement enforces this requirement It is not necessary to include this PARAM since YES is the default but you must not use PARAM OGEOM NO Finally note that NX Nastran writes the Constraint modes and Vibrata expects to read them using the nodal displacement coordinate systems not the basic system Therefore for enforced Vibrata Documentation Preparing Nastran Input files motion analyses that depend on Constraint modes Vibrata always takes the prescribed motion to be in the driven node s displacement coordinate system Response Spectrum analysis is handled differently as described below The RSOPT and RSCON PARAM cards are not available in Femap you must either export the deck and edit it or add these cards as text These cards are not recognized by any version of Nastran except NX If you want to use some other Nastran you will have to use a DMAP alter to generate the required output See Section 7 6 to read about the additional data required Additional modified params for Vibrata enforced motion PARAM POST 2 PARAM OUGCORD GLOBAL PARAM RSOPT 1 PARAM RSCON YES PARAM OGEOM YES DOF available for enforced motion USET U2 44 123 USET U2 49 123 Figure 2 4 Include a U2 USET and special PARAMs to enable enforced motion excitation The example
42. alysis so create a contour request for displacement and acceleration UT AT at all nodes Figure 4 82 Note that the Select nodal variables toggle is checked and inactive the normal modes solve did not request any elemental data Solve the event but do not plot the contours at this time 95 Vibrata Documentation Example Problems Stress Item Label Variables Recovery Intervals Elem XY Contour Group ALL NODES AND ELEMS UT AT none ResSpec Contoui Output Variables Select nodal variables 4 U Nodal Displacements Interactive V UT Translations F UR Rotations F V Nodal Velocities 4 A Nodal Accelerations Plot XY IV AT Translational Accelerations Plot F AR Rotational Accelerations splacements Contou X Results Contour Groups ALL_NODES_AND_ELEMS Shell Beam Stress Recovery Point none v Output Intervals Contour Interval Set ResSpec Contours Single frame containing sum of all modal responses for entire spectrum Cx o oe Figure 4 82 Request translational displacements and accelerations at all nodes 61 Copy this event Change the summation method to SRSS and change the event name to reflect this Figure 4 83 Solve the SRSS event 96 Vibrata Documentation Example Problems File Functions Help Everts Name Frame RSpec Abs Modal Respons S wraTest frame frame modfem Frame RSpec SRSS Modal Respons S vraTest frame
43. ansient Function Attributes Name RCS UnitFrc hist Attributes Interpolation Type LinLin Y Axis Type Force zj Choose a destination file S wraTest iSat lSat_excitations fer 9c Con Figure 4 95 Save the ISat thruster forcing function to a file 108 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name 1 Force Node 3687 basic 3 20 0 RCS UnitFrc hist 2 Force Node 3956 basic 3 20 0 RCS UnitFrc hist 3 Force Node 4225 basic 3 20 0 RCS UnitFrc hist 4 Force Node 4494 basic 3 20 0 RCS UnitFrc hist Rx Ry Rz 4 m F Use nodal displacement coordinate system Node Selection Node Groups ERES Sef correlated cose Figure 4 96 Scale the function by 20 and then create the final excitations 71 Go to the Modal Settings tab This model has too many modes to set individually so bring up the damping dialog and use its damping schedule to set the damping of all modes to 196 Figure 4 97 Rigid body modes will remain at 096 damping 109 Vibrata Documentation Example Problems Solver Exckations Modal Settings Output Frequency Modal Damping Translational Modal Effecti R Hz Viscous Structural x Y 0 0000 0 00 0 00 0 0000 0 00 0 00 Modal Viscous Damping Sum mary User Matrix User Matrix Mode _ Frequency Schedule
44. asses on the other two 20 Vibrata Documentation Example Problems nodes The masses are only allowed to translate in the X direction The two natural frequencies of the system are about 5 apart The model is located in the examples 2dof directory As with the single DOF example there are two models present here called 2dof_modes_base dat and 2dof modes fixed dat You must always use 2dof modes base dat with Vibrata as it meets all the requirements described in Section 2 1 The other file is provided to illustrate the differences between a deck that is Vibrata compatible and one that is not Y 1 A v zii y is Figure 4 2 Two DOF spring mass model 4 1 3 Two Dimensional Frame The two dimensional frame model Figure 4 3 consists of an array of bar elements three columns wide and four rows high Concentrated mass elements are located at each intersection of bar elements while the bars themselves are massless thus making this a lumped mass approximation The bottom node of each outer column is connected by a rigid element to the bottom node of the center column which is fixed in all six DOF Enforced motion in X translation is enabled at this node Out of plane Z translation and X and Y rotation are constrained at all other nodes The model is located in the examples frame directory This folder includes a file with sample excitation functions 21 Vibrata Documentation Example Problems Figure 4 3 Two dime
45. blems r Functions Manage vraModaiFrequencylnto o Name FunctionType OrdNumDataT C End Increment Points Function Sets 15 5 10 15 20 Frequency Function Attributes Name Const 10g 1to20Hz Attributes Interpolation Type LinLin Y Axis Type Acceleration 6 v Figure 4 12 Use the Function Manager to create an acceleration function L 4 Click the Create button to save the new function into an fcn file Call this file l1dof example functions fcn and place it in the 1dof folder Figure 4 13 31 Vibrata Documentation Example Problems Figure 4 13 Save excitation function to new function file 5 With your new function selected in the Function Manager click Done to return to Event Manager then click OK to close the Enforced Motion dialog and create the new excitation It will be listed in the table on the Excitations tab 4 Assign 2 5 damping to the single mode Select the Modal Settings tab double click in the Viscous cell under Modal Damping for the mode and enter a value of 2 5 Figure 4 14 32 Vibrata Documentation Example Problems Output Frequency Modal Damping Translational Modal Effect Hz Viscous Structural X Y vows 0 00 100 00 100 00 Select Modes Effective mass threshold 1 0 Effective mass directions pA AT AL J Active Rigd Mass None Inactive Residua
46. d data transfer issues Additionally you can develop custom dynamics solvers and new solution methods using ordinary MATLAB scripting 1 1 Features The Vibrata user interface offers extensive capabilities for defining complicated dynamic analyses At the same time it provides useful defaults that will be acceptable in many cases thus making it easy to define basic analyses as well Vibrata features include e nteractively select and view the FE model and mode shapes list natural frequency and modal effective mass and assign modal damping values e Add enforced motion and static correction data constraint modes attachment modes residual vectors when available from the modes solve e Define type of analysis and solution range and resolution e Define excitation functions interactively or import them from test results or other data sources e Solve for modal domain responses Vibrata Documentation Overview e nteractively select physical responses to recover e Recover and store physical responses at any or all physical degrees of freedom DOF as XY functions or field contours e Manage the input environments event definitions and physical responses e Run in interactive mode for defining and solving dynamic events Run in batch mode for solving events that are already completely defined If you want to get started quickly you may want to look at the example problems Section 4 before you delve into the User Gui
47. de Section 3 which covers everything in detail However you must familiarize yourself with Nastran input file requirements defined in Section 2 1 1 2 Architecture Vibrata has been developed around Femap and MATLAB Its primary user interface called the Dynamic Event Manager is a separate process that starts and drives its own Femap session and its own MATLAB session to act as its FEM server and Solver server respectively If there is already a Femap session running on your computer Vibrata connects to that instead of starting another one but it will always start its own MATLAB session MATLAB is the computational engine that solves the modal dynamics algorithms and it is also the basis of the Function Manager and XY Plot user interfaces that create manage and display excitation and response functions Figure 1 1 shows a schematic of the Vibrata components The separate processes communicate with each other through COM interfaces Vibrata Documentation Overview Dynamic MATLAB Event Manager Custom GUI Select FEM solver excitation Manager output XY Plot COM Interfaces MATLAB Custom Kernel FE Display a us Mesh Manage Contours Functions COM API COM API Figure 1 1 Overview of Vibrata components Vibrata includes a special version of IMAT the Interface between MATLAB Analysis and Test MATLAB toolkit developed by ATA IMAT enables much of the graphical computational and file import
48. directly in the modes tableroa pL PEE 33 Request XY output for total and flexible X accelerations at node 32 34 Solve for the requested OUtPUL 0 cece cece eee e ee memes 35 Results are available for requests in green text Display them 35 Select and plot both requested acceleration responses at once 36 Set the number of points at which you want to compute responses 37 With only 2 modes you can assign damping directly in the damping jen LEE 38 Define a point force excitation on node 13 in the X direction 39 Create a new a function with a constant 10 Ibf amplitude from 0 to 30 pape En EE 40 Request X acceleration response plots for all three nodes 41 Plot the acceleration response of all DOF sssssseeseses teen eed 42 Create a new model frequency event using the frame model 43 Apply a forcing function to the available enforced motion DOF 44 If necessary reopen the file containing the excitation function from the ldof example 225 anite textes aead tan crak cenit a LLLI aia 45 Change the copied function to have a range from 1 to 40 Hz 46 Edit the new function s name and make it use log log interpolation 47 vi Figure 4 30 Make the function uneven and give it non constant amplitude 48 Figure 4 3
49. e 2 7 Figure 2 8 Figure 2 9 Figure 2 10 Figure 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Figure 4 5 Figure 4 6 Figure 4 7 Figure 4 8 Figure 4 9 Figure 4 10 Figure 4 11 Figure 4 12 Figure 4 13 Figure 4 14 Figure 4 15 Figure 4 16 Figure 4 17 Figure 4 18 Figure 4 19 Figure 4 20 Figure 4 21 Figure 4 22 Figure 4 23 Figure 4 24 Figure 4 25 Figure 4 26 Figure 4 27 Figure 4 28 Figure 4 29 List of Figures Overview of Vibrata components s ssrersssserersrssererrrrrerrrrrrrr eme messe see e eene 3 TITLE card ensures that Femap creates a valid analysis set and output cct when Geos te KURS beets teh san duration bins de pte dened tereteb sil T E T AN 7 MODFEM file with required analysis set and output sets sese 7 NX Nastran cards including DMAP alter to enable load set excitation 9 Include a U2 USET and special PARAMs to enable enforced motion excitation ois coven aves vied rore yx ee wees ev enced ean KR NA KA KR ev tux ete HE eee Vek ae 10 Alternate deck for enforced motion using DMAP alter cccee eee e eee rara 11 Include the Vibrata DMAP alter to get coupled modal damping matrices 12 Add a PARAM RESVEC card to get residual modes for applied forces 13 You can get residual modes by defining a U6 USET without any actual KEEL SENTENSER hotties nse Li ic Mei eri e ed P Souetiens sun ie c RUM 14 Add PARAM RESVINE
50. e 4 71 Figure 4 72 Figure 4 73 Figure 4 74 Figure 4 75 Figure 4 76 Figure 4 77 Figure 4 78 Figure 4 79 Figure 4 80 Figure 4 81 Figure 4 82 Figure 4 83 Figure 4 84 Figure 4 85 Figure 4 86 Figure 4 87 Figure 4 88 Figure 4 89 Figure 4 90 Figure 4 91 Figure 4 92 Figure 4 93 Figure 4 94 Figure 4 95 Figure 4 96 Figure 4 97 Figure 4 98 Figure 4 99 Figure 4 100 Figure 4 101 Figure 4 102 Figure 4 103 Figure 4 104 Figure 4 105 Figure 4 106 Figure 4 107 Figure 4 108 Figure 4 109 Figure 4 110 Figure 4 111 Figure 4 112 The FastRMS contours are visually identical to those from the original Jm Mr EL 85 Copy the original rigid base event the new one will exclude modes with negligible effective mass meeseeserersrsseserrrsrrsrrrrrrrrrer rss rare memes nemen 86 Select modes below 0 1 modal effective mass for all translations 86 All but 46 of the 167 modes are turned off but 98 of the effective mass remains P 87 The mass filtered contours are visually identical to those from the original event ice Ha RE ue a Ryan e xEU EET Y e e vA E Dep KRA RS EKRAR 88 The node 5577 response shows differences at high frequencies but RMS Values matcli iuis ere rcredie et ei EFE EP DEI MER EUER RE E DOR PEE REL M 89 The adapter leg axial force again shows differences only at high TFEQUENCIOS Ln 90
51. eria and Deformed views from Femap s Post toolbar 65 The displacement results are shown in Figure 4 87 and Figure 4 88 For all of the displacement plots the color bar has been set to 10 intervals with the range from 0 34 to 2 1 inches The acceleration results are in Figure 4 89 and Figure 4 90 The color bar range in these plots is from 20 to 140 in s 99 Vibrata Documentation Example Problems Output Set Response Spectra Output AnSet B Deformed 2 083 T1 Translation Displacement Criteria T1 Translation Displacement Output Set Response Spectra Output AnSet 7 Deformed 1 969 T1 Translation Displacement Criteria T1 Translation Displacement Figure 4 87 Displacements for a absolute value and b SRSS methods 100 Vibrata Documentation Example Problems Output Set Response Spectra Output AnSet 8 Deformed 2 069 T1 Translation Displacement Criteria T1 Translation Displacement Output Set Response Spectra Output AnSet 3 Deformed 1 969 T1 Translation Displacement Criteria T1 Translation Displacement Figure 4 88 Displacements for a NRL and b NRC methods 101 Vibrata Documentation Example Problems Output Set Response Spectra Output AnSet B Deformed 2 083 T1 Translation Displacement Criteria T1 Translation Acceleration Output Set Response Spectra Output AnSet 7 Deformed 1 969 T1 Translation Displacement Criteria T1 Translation Accelerat
52. eshow Legend Rems per Plot 6 Figure 4 37 Compare the responses of the top corner node for the two inputs 4 3 Random Analysis For this example you will use both of the I Sat launch models You will start with the single point base model and then repeat the analysis with the four point base With the four point base you will use both correlated and uncorrelated input to see the effects of correlation and to illustrate the correlation definition dialog Finally you will return to the single point model and repeat the analysis having deactivated any modes with no significant modal effective mass in the excitation direction 4 3 1 Create Common Acceleration PSD All examples in this section will use the same excitation function You can create it before you create any events 24 n the Event Manager access the Function Manager via the Functions menu 55 Vibrata Documentation Example Problems Vibrata Advanced Modal Dynamic Functions Function Manager Figure 4 38 Access Function Manager directly from Event Manager menu 25 In the Function Manager click New to bring up the New Function dialog As shown in Figure 4 39 set the Function Type to PSD the X Spacing to Uneven and the number of points to 6 Key in the frequencies and amplitudes as shown Set the Y Axis Type to Acceleration EU so the Y values will be in engineering units in this case in s Hz rather than g Hz The Interpolation Type m
53. fects of thruster start stop 121 Frame model showing nodes of special interest cccceeeeeeee teen eee es 122 Solver setup for frame model transient analySiS ccceeeeeeee eee eee ea es 123 Forcing function will be applied at node 10 in a direction taken from the FEM QGOME LIY lt deest euer eben des rad Pee o REIR vues RANG RARE Sedd du 124 viii Figure 4 113 Figure 4 114 Figure 4 115 Figure 4 116 Figure 4 117 Figure 4 118 Figure 4 119 Figure 4 120 Screen pick node 10 then node 9 to define the force direction 125 Define a unit force triangular pulse function sssssrerssesrrrrsrrrrrrrrrrrrrr eee eee ed 126 Save the new function to the frame excitations file cccceceeeee rene es 127 Apply the forcing function to the Vibrata event cc cee eee eect eee eee 127 Set the damping of the model to 10 for mode 1 5 for mode 2 and 196 elsSeWleres dois tete iM as tae AM Sea ork dard los Sake Monat A ML in i dea eee 128 Request displacement plots for node 15 ccccece cece eeeeeeeeeeeeceeeeneeeeeees 129 Request displacement UT contours for the first 3 seconds of the Qu I 130 Transient displacements for node 15 sssssssssresrrerrerrrrr rer rrrrr rr rr ers rr rar rr rar na 131 Vibrata Documentation Overview 1 OVERVIEW Vibrata is a comprehensive easy to use modal dynamics tool for predicting structural dynamic response to trans
54. fic Analyses Appendix A Additional Output2 Data for Specific Analyses 139 Vibrata Documentation Using Data from Non Nastran Solvers Appendix B Using Data from Non Nastran Solvers 140
55. group you may want to display only that group Figure 4 104 Solver Exckations Modal Settings Output Stress Item Label Recover y Inter vals Contour Group ALL NODES AND ELEMS none Trans Contours Contour Group RCS_PANEL_SHELLS Y Output Set PEAK AnSel 7 Elemental Contour Plate Top von Moes Stress Figure 4 103 Peak von Mises stress contours in RCS panels 115 Vibrata Documentation Example Problems Output Set PEAK ArSet 7 Elemental Contour Piste Top von Mines Sbess Figure 4 104 Von Mises results with only the RCS panels group displayed 76 There appears to be a significant stress concentration where the instrumentation package support attaches to the bus Create a contour request for the peak stresses in the BUS SHELLS group with the same settings used for the RCS panels Solve this new request then select it in the table and click Plot Contour again Figure 4 105 This time display only the BUS SHELLS group in the contour plot Figure 4 106 There is indeed a stress concentration and the stress is nearly seven times higher than in the RCS panels 116 Vibrata Documentation Example Problems Solver Exckations Modal Settings Output Contour Recovery Intervals Item Label Contour Group ALL_NODES_AND_ELEMS Contour Group RCS PANEL SHELLS Contour Group BUS SHELLS none Trans Contours All Trans PeakStress All Trans PeakStress Figure 4 105 Select the BUS SHELLS contour request a
56. gure 4 57 Add the rigid base results to the those available for plotting 74 Figure 4 58 The Y acceleration responses for the two events are very different 75 Figure 4 59 Copy the uncorrelated event the new event will have correlated inputs 76 Figure 4 60 Define 0 degree phase lag correlations from the first input PSD to the other three centers c bru eli b ver eu ach Rn arate Ru tE eet mates BIR Ar AD 77 Figure 4 61 Finish defining O dgree phase shift correlations among all the input PSDs 78 Figure 4 62 The Excitations tab will show the defined CSDs but not their conjugates 79 Figure 4 63 RMS von Mises stress in satellite bus shell elements 4 point base correlated cg ue xen ERA RN DA ede ERA EXPE ve eee ede isle 80 Figure 4 64 RMS accelerations rigid base a 4 point uncorrelated b 4 point correlated c t ee terret acr rb e ire OUT bees e OSCDIX TN EDU R 81 Figure 4 65 The correlated 4 point results match the rigid base results for Node 5577 Y accelera tioN o PET 82 Figure 4 66 The correlated 4 point results also match the rigid base results for launcher leg forces ssssssssssssssssssessesne ee E re e a enne 83 Figure 4 67 Copy the original rigid base event the new one will use FastRMS contour calculation eT 84 Figure 4 68 Turn on the Use FastRMS toggle on the Excitations tab sssssessses 84 vii Figure 4 69 Figure 4 70 Figur
57. have loaded the model and results into Femap use the Entity Editor Vibrata Documentation Preparing Nastran Input files as shown in Figure 2 2 to determine what case name was assigned in Nastran where FREE MODES SMALL appears in the Notes entry then rename the normal modes analysis set to match that name Note that it is possible to create Nastran decks that put nothing at all in this location In that case this remedy will not work and you will have to solve the model again with a proper TITLE card 2 1 3 Load Set Excitation If you want to use a time or frequency dependent scaling function to multiply the forces in a static load set you must include the highlighted statements in Figure 2 3 You can use any combination of point forces distributed loads and body forces Note the presence of the LSEQ entries Each of these refers to FORCEi PLOADi GRAV or other static load cards field 4 Those cards define the actual physical loads applied to the model and obviously they must also be present in the file The LSEQ cards simply tell NX Nastran that these are the static loads to include in the generalized force matrix it writes to the OP2 file Note also the presence of a DMAP alter called vibrata nx7 This is required with NXN7 but is not needed with NXNB8 It is provided by ATA as part of Vibrata in the top level directory of your Vibrata installation The figures show the default installation path recommended by ATA you mus
58. he easiest way to learn the basics of Vibrata is to run some analyses using the example models provided This section introduces four different models shows how to load the models and their modal results in Femap and then guides you through a number of analyses using them 4 1 Descriptions of Example Models Each of the example models is provided as a Nastran bulk data file They are found in the examples subdirectory of your Vibrata installation To prepare the models for use with Vibrata follow the instructions in Section 4 1 5 4 4 1 Single DOF Spring Mass Model The single DOF spring mass model Figure 4 1 consists of a spring grounded at one end with a lumped mass attached to the other SPCs allow the mass to move only in X direction translation The model is located in the examples 1dof directory In fact there are two models in that folder called 1dof modes base dat and 1dof modes fixed dat You must always use ldof modes base dat with Vibrata as it meets all the requirements described in Section 2 1 The other file is perfectly valid for a typical Nastran SOL 103 analysis but it will not produce all the data needed for Vibrata it is provided to illustrate these differences L Figure 4 1 Single DOF spring mass model 4 1 2 Two DOF Spring Mass Model The two DOF spring mass model Figure 4 2 consists of three nodes connected by two springs in series with the left node fixed to ground and lumped m
59. hould activate the INST PKG FEM group Figure 4 47 63 Vibrata Documentation Example Problems me i Cf C A ee Ea eS uy ela a pum ey ey oF Elemertal Contour Plate Top von Mises Stress 5 Output Set RMS AnSet 2 64 Figure 4 46 RMS von Mises stress in satellite bus shell elements rigid base Vibrata Documentation Example Problems Output Set RMS AnSet 2 Nodal Contour T2 Translation Node 5577 u Output Set RMS AnSet 2 Nodal Contour T1 Translation Figure 4 47 RMS acceleration contours for the instrumentation package rigid base 65 Vibrata Documentation Example Problems 34 The highest RMS acceleration occurs at node 5577 for Y acceleration That node also shares the highest Z acceleration although it is lower than the Y direction You would like to know the frequencies at which the largest responses occur so create a Node XY output request for that node and those directions Figure 4 48 You can request X acceleration if you wish but it will clutter the plotting displays Solve this new request and plot the Y acceleration function Figure 4 49 Set the display units to IN G s to see the responses in g Hz rather than in s Hz Solver Exctations Modal Settings Output Stress Contour Recovery Inter vals All Rand_Contours TV Total Velocities none Rand_Contours TVTMAG Total Translational Velocity Magnitude 4 TA Total Accelerations 4
60. ient harmonic random and response spectrum excitation The initial release addresses structures represented by a single finite element model but future releases will handle system level analyses with multiple separate components whose representations may come from many sources The program integrates design analysis and test activities for products for which dynamics is an important issue Vibrata employs a modal post processing approach so you must first solve your finite element model for normal modes The program is best adapted for using results from NX Nastran but MSC Nastran results can be used for many basic analyses Note that Vibrata does impose certain requirements on the contents of your Nastran input files so it is important that you review Section 2 before you solve your model for normal modes Normal modes from other solvers can also be used see 0 for more details Vibrata uses modal data to solve for the specified dynamic responses The software makes it easy to define solve and display responses for both simple and advanced dynamic problems Each dynamic problem is called an event and its definition includes the type of analysis to perform transient frequency response random response spectrum the FEM and modes to use the excitations modal damping solution range and resolution and the physical responses to compute Interactive graphical processing lets you focus on the engineering rather than the data input formats an
61. ifferent 4 3 4 Sat with Correlated Inputs 44 Copy the uncorrelated event for the Apt model from example 4 3 3 and assign the new event a name indicating that it will have correlated inputs Figure 4 59 It will still use the 4pt model 75 Vibrata Documentation Example Problems fre Y Vibrata Advanced Modal Dynamic Analysis 1 0 7 File Functions Help Events Name Type FEM Name a New ISat Rad RanGround Modal Random SvraTestSatNSat sm Launch Rgd modfem ISat 4pt RanGround Uncor Modal Random SWraTestMSatNSat sm Launch 4pt modfem Modal Random Xt RanGround Corr S wraTestSatNSat sm Launch 4pt modfem Figure 4 59 Copy the uncorrelated event the new event will have correlated inputs 45 On the Excitations tab bring up the CSD dialog Select the entire first row of the CSD Matrix table and click the Assign Selected CSD button v Figure 4 60 This prepares the dialog to create correlations from the first input PSD to the other three PSDs Make sure the CSD Type pulldown is set to Phase Lag and the Phase Time lag field is set to 0 degrees When you click the Apply button the defined CSDs are created and the CSD Matrix table is updated Continue selecting rows clicking the button and clicking Apply until the entire matrix is filled Figure 4 61 When you click OK to close the CSD dialog the CSDs appear as additional excitations on the Excitations tab Figure 4 62 The new event
62. in o uw Rea Cesglacement i o L a Displacement Node 15 UT x g grid none basic Real Displacement in Figure 4 120 Transient displacements for node 15 87 Plot and animate the contours by clicking the Plot Contour button Double click anywhere in Femap s graphics window to start the animation Adjust Femap s display parameters in any way you find helpful 181 Vibrata Documentation Creating Custom Solvers 5 CREATING CUSTOM SOLVERS 5 1 The Solver File 5 2 The Solverl nfo File 5 3 The Custom Solver Folder 132 Vibrata Documentation Vibrata MATLAB API For Custom Solvers 6 VIBRATA MATLAB API FOR CUSTOM SOLVERS 6 1 6 2 6 3 6 3 1 6 3 2 6 3 3 6 4 6 4 1 6 4 2 6 4 3 6 4 4 6 4 5 6 4 6 6 4 7 Directory Structure Function Naming Convention Utility Classes vraParam Vibrata Parameter Class VraReqmap Vibrata Request Mapping Class Fcn Vibrata function class Example Solver Initialization Generate Modal Quantities Gather Event Setup for Generating Modal Quantities Calculate Modal Quantities Determine Output Requests Compute Output Cleanup and Return 133 Vibrata Documentation Theoretical Manual 7 THEORETICAL MANUAL 7 1 Normal Modes Analysis 7 2 Viscous and Structural Damping 7 3 Steady State Frequency Response Analysis 7 4 Random Response Analysis 7 5 Transient Analysis
63. inate system It refers to Femap s Coordinate System O which is known as both the Global Rectangular system and the Basic Rectangular system It is a single coordinate system not an agglomeration of many separate systems Nastran users are generally used to saying basic coordinate system when they mean global coordinate system and global coordinate system when they mean the nodal displacement coordinate system at each node In this manual if we want to refer to the nodal displacement coordinate system we will say the nodal displacement coordinate system the global coordinate system is always the same as Nastran s basic coordinate system Vibrata Documentation Preparing Nastran Input files 2 PREPARING NASTRAN INPUT FILES Vibrata gets the data it needs from a Femap MODFEM file so in fact it can use results from any finite element solver that has an interface to Femap However many of the analyses Vibrata offers require the presence of specific data that Femap does not ordinarily read even from NX Nastran This section describes how to prepare NX Nastran input files to make sure they generate all the results that Vibrata needs for specific analyses If you want to use a different FE solver you will have to work out how to make it produce the equivalent data and how to load it into Femap See Appendix A and Appendix B for more details For the most part Vibrata imposes very few and very easy to satisfy but important
64. inition 18 Assign viscous damping of 5 to the first mode and 2 to all other modes 16 On the Modal Settings tab click the Damping button to bring up the Modal Damping Definition dialog 17 In the Viscous Damping Schedule table enter a value of 2 in the Damping 96 column and leave the frequency column blank 18 Click the Apply Schedule button LA In the Damping Summary table each mode now has 2 damping Change the first mode s damping to 596 by double clicking on that cell in the Damping Summary table and typing in the value Click OK to apply the damping changes and close the dialog 49 Vibrata Documentation Example Problems Frequency Modal Damping Translational Modal ette C Mode Hz Viscous Structural X Y Modal Viscous Damping Summary User Matrix User Matrix Mode Frequency Schedule Diagonal Off Diagonal Ratio Diagonal Off Diagonal Ratio No Hz Yo 96 Mean Max Mean Max 1 2 3 4 5 6 7 8 0995 Ps 2 9417 2 00 5 1955 2 00 7 3582 2 00 11 1389 2 00 15 4937 2 00 15 5814 2 00 31 4784 2 00 Modal Damping Matrix File Name Matrix Variable Matrix Usage None Figure 4 32 Apply 2 damping to all modes via damping schedule then set mode 1 to 5 19 On the Output tab create a Node XY output request for flexible and total X translations UTx and TUTx for the center base node 2 center second floor node 8 and upper right corner node 15 as shown in Figu
65. inor bug fixes and enhancements Version 1 0 3 Bug Fixes Fix bug processing constraint modes when model includes both shells and solids Other minor bug fixes and enhancements Version 1 0 2 Enhancements Allow user to enter function Name and Interpolation Type directly on new function creation form rather than having to go into Attributes Bug Fixes Fix TIER 940 Other minor bug fixes and enhancements Version 1 0 1 Enhancements e Significant performance improvement reading mode shapes from models with multiple element types Bug Fixes e Fixed bug in Fast RMS solver where it would error on when solving for stress contours Version 1 0 0 e Initial release Vibrata is a trademark of ATA Engineering Inc 2004 2015 ATA Engineering Inc Vibrata utilizes technology from the IMAT and IMAT FEA MATLAB toolboxes also developed by ATA Engineering For more information visit http www ata imat com List of Tables Table 2 1 Supported NX Nastran enforced motion datablocks ssssrsrrrrrrrrrrrrrrrrrrrrrrrr rr na 15 Table 2 2 Nastran element types supported by the Vibrata translator ssss 16 Table 4 1 Maximum response level for each summation method ssessssss 104 Table 8 1 Vibrata environment variables and their meanings essesssssssse 137 Figure 1 1 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figur
66. ion Figure 4 89 Accelerations for a absolute value and b SRSS methods 102 Vibrata Documentation Example Problems Output Set Response Spectra Output AnSet 8 Deformed 2 069 T1 Translation Displacement Criteria T1 Translation Acceleration Output Set Response Spectra Output AnSet 3 Deformed 1 969 T1 Translation Displacement Criteria T1 Translation Acceleration Figure 4 90 Accelerations for a NRL and b NRC methods 103 Vibrata Documentation Example Problems 66 The results are summarized in Table 4 1 The SRSS method produces the lowest responses since it sums the modal responses as if they are all out of phase while the absolute value method produces the highest responses since it sums the modal responses as if they are all in phase The NRL results in this example are between these two because it sums modal responses as in phase if it considers them closely spaced and out of phase if not closely spaced This makes the NRC results somewhat surprising Since it uses the same closely spaced mode parameter as the one we selected for the NRL case we might have expected its results to match the NRL results yet they are indistinguishable from the SRSS results There is a significant difference between the NRL and NRC methods that accounts for this While both treat closely spaced modes as in phase NRL also treats the maximum response mode as in phase with all of the closely spaced modes Looking a
67. is now ready to solve 76 Vibrata Documentation Example Problems Solver Exckations Modal Settings Output Type Item Label S 11 Accel GroundTransport S 22 Accel GroundTransport S 33 Accel GroundTransport S 44 Accel GroundTransport Figure 4 60 Define 0 degree phase lag correlations from the first input PSD to the other three 77 Vibrata Documentation Example Problems 50 2 SAN 2 3 G 3 G 4 sa 9 sQ 9 v We elapso 3 Accel 5632 3 Groundlransport s 4 m a To S 44 Accel 5633 3 GroundTransport g Figure 4 61 Finish defining O dgree phase shift correlations among all the input PSDs 78 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output 1 2 3 4 5 6 7 8 9 m e Type Item Label CSys Dir Scale Factor Function Name Accel Motion 5630 disp 0 GroundTransport Load Accel Motion 5631 disp GroundTransport Enforced Motion Accel Motion 5632 disp 0 GroundTransport CSD Accel Motion 5633 disp GroundTransport Phase CSDL 12 0 deg Use FastRMS Phase CSDL S 1 3 0 deg Phase CSDL S 1 4 0 deg Phase CSDL S 2 3 0 deg Phase CSDL S 2 4 0 deg Phase CSDL S 3 4 0 deg Delete Figure 4 62 The Excitations tab will show the defined CSDs but not their conjugates 46 Go to the Output tab and solve this new event The RMS von Mises contours here Figure 4 63 are ide
68. l gt Mass Set Mode Status Active Rigd Plot Mode Shapes BS Es LE BG Figure 4 14 Assign 2 5 modal viscous damping to the mode directly in the modes table 5 Create a Node XY output request for the free DOF Request X direction output at node 32 for Total Accelerations TATx and Relative Accelerations ATx as shown in Figure 4 15 When you click OK or Apply on the Nodal XY Plot dialog the request appears in the output request table as shown in Figure 4 16 33 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output 4 amp 7 AR Rotational Accelerations ATMAG Translational Acceleration Magnitude 7 TU Total Displacements TUTMAG Total Translation Magnitude C Tv Total velocities TVTMAG Total Translational Velocity Magnitude m TA Total Accelerations mj aL otal Transiational Accelerations v TATX C Return output in the displacement coordinate system Node Selection Nodes 32 2 C Interactive Plot XY Plot Contour X Results Figure 4 15 Request XY output for total and flexible X accelerations at node 32 6 Solve plot and compare the two output results 1 On the Output tab click Solve Figure 4 16 to compute the frequency response 34 Vibrata Documentation Example Problems Output Variables ATx TATx Figure 4 16 Solve for the requested output 2 The text of the request turns
69. ll Beam Stress Recovery Point re Cx Ce Ce Figure 4 50 Request axial forces in the launcher adapter legs 68 on Force by Ha Reach 4 3 3 36 37 5623AXF 5625AXF 5627 AXF 5629AXF 4 S831AXF 5633AXF Vibrata Documentation Example Problems Power Spectral Density RMS 14 9958 RMS 31 4568 RMS 67 2282 RMS 69 3826 RMS 72 7298 TF RMS 79 5235 Frequency Hz Figure 4 51 Axial forces in the launcher adapter legs rigid base Sat with Uncorrelated Input at Each Adapter Leg In Femap import the launch model with four independent base nodes ISat Launch Sm Apt dat Figure 4 4 along with its results ISat Launch Sm 4pt op2 and groups ISat Launch Sm 4pt groups neu Save the model as ISat sm Launch 4pt modfem In the Event Manager copy the event from 4 3 2 using the Copy button and then assign a new name to the new event Figure 4 52 Use the Select FEM button to select the modfem file the 4 point model You will see a dialog warning of possible changes to excitations and output requests for the new FEM confirm that you want to make the change The two events will be identical in their modal settings and output requests although the new event will have no results yet The excitation function will also be the same as before but we now have four input locations instead of only o
70. ly RMS output eie xdg ER ee sees esd deed Ea EEE a E 62 Figure 4 45 Select von Mises Stress for the first contour plot and turn off averaging 63 Figure 4 46 RMS von Mises stress in satellite bus shell elements rigid base 64 Figure 4 47 RMS acceleration contours for the instrumentation package rigid base 65 Figure 4 48 Request Y and Z direction total accelerations for node 5577 66 Figure 4 49 Node 5577 total Y acceleration in g Hz units rigid base suus 67 Figure 4 50 Request axial forces in the launcher adapter leOS sssssrrsrsrresrerrerrrrrerrrrrrne rerna 68 Figure 4 51 Axial forces in the launcher adapter legs rigid base sssssssessss 69 Figure 4 52 Use the Copy button to start a new event from the event just completed sut via ate nts Apr t ree ER Rie E RENE UA Ua d begun Oe eR EVI es dev rua T donee Ee Pd 70 Figure 4 53 Apply enforced motion in the Z direction at all four base nodes 71 Figure 4 54 Delete the automatic CSD entries 0 2 2 0 ccc eee eee ee rr rr rr rr Resa 71 Figure 4 55 RMS von Mises stress in satellite bus shell elements 4 point base uncorrelated ence rei oe Kaare ee ebay ed NAN RAN RR RA ENA ean Ra overt AK Kna EP RK KSR ENA RS 72 Figure 4 56 RMS acceleration contours for the instrumentation package 4 point base UNCOPFSlatG san enda stenens ere san eee nehme eee KITE RAA sene ne 73 Fi
71. me modfem for the FEM Give the event a recognizable name such as the one shown in Figure 4 25 42 Vibrata Documentation Example Problems Geer Made Set in od c FE PD FRAME FOR BASE EXCITATIONS Inch Poundf FEM Solver I Analys Type Data for FrequencyfRandom Analysis Exckation frequency selection Log spacing at Modes v Exckation lower bound Hz 1 0 No points in range 20 ExcRation upper bound Hz 1 0 No points near modes 5 b Modal Frequencies V Undamped Damped Max Response Figure 4 25 Create a new model frequency event using the frame model 16 On the Excitations tab select Enforced Motion select the one available DOF and then click the t 9 button Figure 4 26 43 Vibrata Documentation Example Problems Use FastRMS Figure 4 26 Apply a forcing function to the available enforced motion DOF 17 Define both functions for the analyses 11 1n the Function Manager dialog click the Source Files button and open the function file from the 1DOF example Figure 4 27 44 Vibrata Documentation Example Problems Functions Piot sorcaries_ rM E m ja Name FunctionType OrdNurnDateT New _ My Network File name idof_example_functions fen gt Files of type fan FCN Files fcn Figure 4 27 If necessary reopen the file containing the excitation function from the 1dof example 12 Select
72. modfem UNG MASS AT 10 HZ BASE EXCITE Inch Pound f Soker Exctatons Modal Settings Output Solver Analysis Type Modal Frequency v Data for Frequency Random Analysis Variables for Custom Solvers Excitation frequency selection Log spacing at Modes zj Name Excitation lower bound Hz 1 No points in range 20 Excitation upper bound Hz 1 No points near modes 5 bx Modal Frequencies 7 Undamped F Damped E Max Response Qo Organize New folder X Favorites Name Date modified Typ amp 1dof modfem 8 23 2013 240 PM Fem Z Libraries Figure 4 10 Create a new frequency response event and select the FEM on which to base it 3 Create a constant acceleration excitation on the enforced DOF with a frequency range that includes the natural frequency of the system 1 Select the Excitations tab and click Enforced Motion 2 On the Enforced Motion dialog select the one available DOF and assign an excitation function to it by clicking the t 9 button to bring up the Function Manager Figure 4 11 29 Vibrata Documentation Example Problems Assign Forcing Functions to Valid DOF Treat excitation as rigid body Figure 4 11 Create a new enforced motion excitation 3 In the Function Manager Figure 4 12 create a new function Define it as a frequency function with acceleration in G Give it a constant magnitude of 10G from 1 to 20 Hz 30 Vibrata Documentation Example Pro
73. n Forcing Functions to Valid DOF Treat excitation as rigid body Scale Type Function Name Figure 4 77 Assign an enforced motion function to direction 1 57 n the Function Manager use the Source Files button to open the frame_excitations fcn file from Section 4 2 3 If you have not created that file yet you will do so here when you finish defining the response spectrum function Define a new velocity response spectrum function as shown in Figure 4 78 Click the Create button and store the function to frame_excitations fcn Figure 4 79 Click Done on the Function Manager main dialog to return to the Event Manager 92 Vibrata Documentation Example Problems Name FunctionType OrdNumDataTypel C e r Functions Piot Math Increment 0 1 Points 4 i 10 10 10 L_ Response Spectrum Function Attributes Y Axis Type Velocity Figure 4 78 Define a Response Spectrum velocity function 93 Vibrata Documentation Example Problems Choose a destination file S wraTest frame frame_excitations fcn Figure 4 79 Store the new function in the frame excitations file 58 Click OK on the enforced motion dialog to finalize the excitation definition Figure 4 80 Note that it uses the basic coordinate system Also note that it is considered part of rigid body motion set this makes no difference here but it would be important if more than one direction were
74. n Input files Element Type Relevant Notes CQUADR See CQUAD4 CTRIAR Composite ply results are not supported Nastran limitation CROD CONROD Stress strain is stored in the Femap S11 component CTUBE CTRIA3 See CQUADA CTRIA6 Not supported as of this Vibrata version Complex results will not be PCOMP a supported Nastran limitation 2 3 Supported Nastran Versions and Solution Types Vibrata supports both MSC and NX Nastran although NX Nastran is clearly the preferred solver In most cases any version of MSC or NX Nastran is acceptable As you have seen from the preceding sections however some capabilities such as enforced motion response and thus response spectrum analysis and load set excitation require a custom DMAP for some NX Nastran versions If you are using a newer version of NX Nastran and you encounter problems with Vibrata please let ATA know via the TIER system see Figure 3 6 c ATA will not provide support for enforced motion and load set excitation for MSC Nastran unless requested to do so by users If you would like to make that request you can also do that through the TIER system Of course a skilled DMAP programmer can make MSC Nastran produce the required data just as ATA has done for NX Nastran and Vibrata will use it as long as it is stored in the OP2 file according to Vibrata s expectations Since Vibrata uses a modal post processing approach it naturally needs modal results to
75. nal event does However the RMS values for the two cases match to 3 significant digits for both acceleration and axial force In these plots the blue curve is for the current mass filtered event and the green curve is for the original all modes active event 87 Vibrata Documentation Example Problems Output Set RMS AnSet 4 Output Set RMS AnSet 4 Nodal Contour T2 Translation Elemental Cortour Plate Top von Mises Stress Figure 4 73 The mass filtered contours are visually identical to those from the original event 88 Vibrata Documentation Example Problems E Total Acceleration Node 5577 TAT y qg grid none basic RMS 1 1317 ILS Total Acceleration Node 5577 TAT_y_g_grid_none basic RMS 1 1348 Figure 4 74 The node 5577 response shows differences at high frequencies but RMS values match 89 Vibrata Documentation Example Problems Power Spectral Density 5533AXF RMS 80 0166 5633AXF RMS 79 9979 0 ey on Ferce Reach Frequency Hz Figure 4 75 The adapter leg axial force again shows differences only at high frequencies 4 4 Response Spectrum Analysis The 2DOF model Figure 4 2 is used to show the difference between different summation techniques ABS SRSS and other for response spectrum analysis 54 f you have not already loaded the frame example model Figure 4 3 into Femap do so now In Femap import
76. nd plot its results Y Output Set PEAK AnSet 7 Elemental Contour Plate Top won Moes Sterns Figure 4 106 Von Mises results with only the BUS SHELLS group displayed 117 Vibrata Documentation Example Problems 77 Now we want to be sure that the solar arrays and instrument package do not fall off due to these thruster firings so create Element XY output requests for beam forces and moments in the elements that attach them to the spacecraft bus Figure 4 107 118 Vibrata Documentation Example Problems 71 S Stress in Shells Solids SINY Stress Invariants E Strain in Shells Solids EINY Strain Invariants SSR Shell Stress Resultants SR Stress in Rod SB Stress in B EB Strain in Bars v BFM Beam Forces and Moments SFM Spring Element Forces and Moments SFINV Spring Force Invariants Element Groups LC a 4 m gt a Shell Beam Stress Recovery Point All hd Cx Cw Co Figure 4 107 Request beam forces in elements that attach appendages to bus 119 Vibrata Documentation Example Problems 78 Solve again and then click Plot XY Figure 4 108 The forces in the instrument package boom element are shown in Figure 4 109 which also shows when the thrusters are firing Note that we have displayed the forcing function on the plot to make clear when thruster firing starts and stops Display the other element responses as you wish Solver Excka
77. ne so we will have to redefine the excitations 69 Vibrata Documentation Example Problems Events Name Type FEM Name ISat Rad RanGround Modal Random SNvraTestSatNSat sm Launch Ragd modfem Modal Random SNvraTestSatNISat sm Launch 4pt modfem a ame Mode Set FEM Units S lvraTestUSatUSat sm Launch 4pt modfFem M LAUNCH 4PT MODES TO 400 HZ inch Pound f v FEM Solver Analysis Type Modal Random Data for Frequency Random Analysis Variables for Custom Solvers Excitation frequency selection LO9 spacing at Modes Y Name Excitation lower bound Hz 1 No points in range 20 Excitation upper bound Hz 1 No points near modes 5 b Modal Frequencies V Undamped F Damped I Max Response Figure 4 52 Use the Copy button to start a new event from the event just completed 38 Go to the Excitations tab First select the existing excitation and delete it the node at which it is applied does not exist in this model Next open the Enforced Motion dialog and select the Z direction DOF for all four nodes in the list Use the Function Manager to assign the ground transport PSD function created in Section 4 3 1 to these DOF Figure 4 53 70 Vibrata Documentation Example Problems Assign Forcing Functions to Valid DOF F Treat excitation as rigid body Node Dir Scale Type 5630 2 5631 1 5631 2 5631 3 GroundTransport 5632 Figure 4 53 Apply enforced motion in the Z
78. nge to 100 5 Set the number of points near modes to 10 36 Vibrata Documentation Example Problems VIDA Fite Functions Help Events Geer Mode Set inch Pos 2DOF SPRING MASS BASE EXCITE inch Pound f Z FEM Solver Analysis Type Modal Frequency Data for Frequency Random Analysis Exckation frequency selection Log spacing at Modes z Exckation lower bound Hz 1 0 Exckation upper bound Hz 1 0 b Modal Frequences V Undamped D Figure 4 19 Set the number of points at which you want to compute responses 9 On the Modal Settings tab assign 1 596 damping to mode 1 and 3 596 damping to mode 2 Double click in the Viscous cell under Modal Damping 96 for each mode and entering the proper value Figure 4 20 37 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Frequency Modal Damping Translational Modal Effecti t Viscous Structural X Y 0 00 75 87 0 00 24 13 100 00 Select Modes Effective mass threshold 1 0 Ab Active Rigid lt Mass None Inactive Residual Mass Set Mode Status Active Rigid Piot Mode Shapes Es E IE 6 Figure 4 20 With only 2 modes you can assign damping directly in the damping table 10 For this event we will apply a point force rather than imposing an enforced acceleration 6 Select the Excitations tab and click Point Force 7 On the P
79. nsional frame model 4 1 4 Sat Inner Planets Exploration Satellite The ISat or Inner Planets Exploration Satellite is a fully developed model of an aerospace structure for which response analysis is a critical part of the qualification phase The model comes in both launch and deployed configurations There are two launch configurations In the standard model ISat Launch Sm 4pt dat Figure 4 4 the bottom apex of each launcher adapter leg has all translational DOF restrained representing a ball joint connection for each leg Enforced motion is also enabled for all twelve of these DOF The other launch configuration has these four points connected by a rigid element to a single central node at which all six DOF are restrained 22 Vibrata Documentation Example Problems ISat Launch Sm Rgd dat Figure 4 5 Enforced motion is enabled for the three translations at this node The deployed configuration ISat Dploy Sm dat Figure 4 6 is a free free model with the launcher adapter removed and the solar panels antenna dishes and instrument package deployed This model includes residual vectors that can improve stress calculations for loads applied at the reaction control system RCS thrusters The models are located in the examplesM Sat directory They are shipped in a Zip file called ISat zip Figure 4 4 I Sat model in launch configuration with four separate attachment points 23 Vibrata Documentation Example
80. nt Mode RARCONS Reaction Force Constraint Mode RAFCONS Beam Force and Shell Stress Resultants Constraint Mode RASCONS Stress Constraint Mode RAECONS Strain Constraint Mode RANCONS Strain Energy and Strain Energy Density deus Effective Ierta D EEMB Modal Matrix Load Set Modal Forces RAFGEN Modal generalized force vectors Table 2 2 contains a summary of the supported element types along with any noteworthy details of their translation Table 2 2 Nastran element types supported by the Vibrata translator Element Relevant Notes Type Forces and moments stress and strain at CL and stress recovery CBAR points C D E F CBEAM See CBAR CBEND CBUSH Forces and moments CELAS CTETRA CPENTA Stress strain results are stored in the coordinate system specified by the PSOLID card CHEXA Nodal stress strain results are only available for CQUAD4 elements if the CORNER option is used in the output request If the CORNER option is specified both nodal and centroidal results are available Stress strain results are left in the coordinate system s in which the CQUADA OP2 results were written usually the element coordinate system See PCOMP notes for details about composite element translation Shell stress resultants Nastran Element forces Femap Section Forces are transformed to the material orientation angle specified for that element CQUAD8 See CQUAD4 Vibrata Documentation Preparing Nastra
81. ntical to those from the rigid base model Figure 4 46 not those from the uncorrelated 4 point base event Figure 4 55 The same is true for the instrumentation package acceleration contours Figure 4 64 Plotting the Y acceleration response PSDs for all three events together confirms this the blue curve for the 4 point base with correlated input is completed covered by the red curve from the rigid base model and those curves have identical RMS values Figure 4 65 This holds for the launcher leg axial forces as well Figure 4 66 79 Vibrata Documentation Example Problems SS ee ee AE i s n 0 a a ee ee me T wn M IH 7 AN y NV VA Hg Hume Es IDEE REESE eS Gee dees Ey I NE C o C aA Elemental Contour Piste Top von Mises Stress Output Set RMS AnSet 3 Figure 4 63 RMS von Mises stress in satellite bus shell elements 4 point base correlated 80 Vibrata Documentation Example Problems Output Set RMS AnSet 2 Nodal Contour T2 Translation Output Set RMS AnSet 2 Nodal Contour T2 Translation Output Set AMS AnSet 3 Nodal Contour T2 Translation Figure 4 64 RMS accelerations rigid base a 4 point uncorrelated b 4 point correlated c 81 Vibrata Documentation Example Problems i i Total Acceleration Node 5577 TAT y g grid none basic p i Total Acceleration Node 5577 TAT y g grid none basic i Total Acceleration
82. oint Force Excitations dialog first select node 13 to receive the applied force Next select the X direction in the Forcing Functions table then click the t9 button to bring up the Function Manager Figure 4 21 Effective mass directions LATS v 38 Vibrata Documentation Example Problems Type Item Label CSys Dir Scale Factor Function Name CSD Use FastRMS Figure 4 21 Define a point force excitation on node 13 in the X direction 8 Create a new frequency function from 0 to 30 Hz with an amplitude of 10 Make sure the Y Axis Type is Force and give the function a name that you will be able to recognize later Figure 4 22 39 Vibrata Documentation Example Problems m Functions Manage vraModairequencyinto FunctionType omaan Attributes Start End Increment Points Function Sets 0 5 10 15 20 25 30 r Frequency Function Attributes I Name Const 10lb Oto30Hz Attributes Interpolation Type LinLin Y Axis Type Force Figure 4 22 Create a new a function with a constant 10 Ibf amplitude from 0 to 30 Hz 11 Request nodal output data at each node On the Output tab click the Node XY button On the Nodal XY Plot Output Requests dialog select acceleration in the X direction ATx and select all three nodes of the model in Femap 40 Vibrata Documentation Example Problems Output Variables
83. ontour Groups INST_PKG_FEM Figure 4 44 Request SVMS for the BUS_ SHELLS and TAT for the INST_PKG_FEM only RMS output 62 Vibrata Documentation Example Problems 32 When the solver has finished click the Output tab s Plot Contour button to examine the results in Femap Use Femap s toolbar button to open the Select PostProcessing Data dialog Figure 4 45 Select Plate Top von Mises from the Contour pulldown Click OK to display the contours Section Cut Options Category 0 Any Output 9 Cut Mode Type 0 alue or Magnitude Data at Corners Output Set 172 RMS AnSet 2 Output Vectors Deformation Element Contour Options je 9 ee LX Parallel Sections Multiple Sections 1713 607 5055 2878 4 59648 Trace Locations 9100022 T1 Translation Total Acceleration Contour Vectors 9100023 T2 Translation Total Acceleration 9100024 T3 Translation Total Acceleration Freebody Display Clee Figure 4 45 Select von Mises Stress for the first contour plot and turn off averaging 33 Since you only calculated stresses for the BUS SHELLS group the best way to view them is to activate that group and set Femap to display only the active group Figure 4 46 With all the desired settings now defined for contour plots you can use Femap s toolbar buttons to select the next or previous data component for display When you get to the translational accelerations you s
84. or any other kind you can determine such modes by examining their modal effective mass Modes with no significant effective mass will simply not respond to enforced motion excitation so we need not include them in our calculations See also Section 7 6 In this example we will deactivate all modes that do not have at least 0 1 of the modal effective mass in at least one of the translational DOF 50 In the Event Manager copy the event from 4 3 2 using the Copy button and then assign a new name to the new event Figure 4 70 85 Vibrata Documentation Example Problems File Functions Help Events ISat 4pt RanGround Uncor Modal Random SAvraTestilSatMSat sm Launch 4pt modfem ISat 4pt RanGround Corr Modal Random SAvraTestMISatNSat sm Launch 4pt modfem ISat Rgd RanGround Fast Modal Random SAvraTestMSatNSat sm Launch Rgd modfem t nd Modal Random S vraTest ISat ISat_sm_Launch_Rgd modfem Figure 4 70 Copy the original rigid base event the new one will exclude modes with negligible effective mass 51 On the Modal Settings tab in the Select Modes panel set the Effective Mass Threshold to 0 1 and the Effective Mass Directions to X Y Z Click the lt Mass button to select the modes whose effective mass is less than that threshold for all the translations Figure 4 71 Solver Excitations Modal Settings Output Frequency Translational Modal Effective Mass 9 Mode Hz x Y z 0 05 0 02 79 51 0 00 0 61
85. p ue ATA ENGINEERING INC Vibrata Advanced Modal Dynamic Analysis User Guide Version 1 4 0 2004 2015 ATA Engineering Inc 13290 Evening Creek Drive S Suite 250 San Diego California 92128 The content of this document is ATA proprietary and confidential information This document is Copyright ATA engineering Inc 2015 All rights reserved No part of this work may be reproduced or used in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without the express written permission of ATA All copies of this document must include the copyright notice as noted above and the other information contained in the paragraph TABLE OF CONTENTS What s N Wy acerca neritic eR ve een dete ae ee ees bee v ae daha eg ee ERT EMR i EOM MEET ET 1 1 1 Features siue ee eM E ERR Eel E ERR REC RR E E E REM REDAS Per TS A ERG 1 1 2 ARCHITEC CHUNG 2 ni Exe De CIS IDEE ee hee Mabe eee ac 2 IMEEM cc ES 3 1 4 Note on the Global Coordinate SYStemM siessssssrersrssrrrrrrrrrrrrrrrrr rr rr rss rr rer rr rn rna 4 2 Preparing Nastran Input files smnsvssssseerrsrssrerrrrsrrerrrrrrrrrerrr rr rr eem eene sensns 5 2 4 NX Nastran Cards for Specific Vibrata Options s sssssssssererssrsrrrrsrrsrerrrrn rr er erna rna 5 2 4 1 General Requirements for Physical Response Recovery
86. p assign a different color to each physical property in the model and then set the element 25 Vibrata Documentation Example Problems color mode to use physical property colors and set the element orientation shape option to show cross sections which also shows shell element thickness Figure 4 7 Read the bulk data into Femap using the Import Analysis Model menu picks 26 Vibrata Documentation Example Problems Rename 14t moes besooo Y Me Flescftype NASTRAN Renaa FO5 OF2 206 v Cmos Figure 4 8 Read the modes results into Femap using the I mport Analysis Results menu picks 27 Vibrata Documentation Example Problems Geometry VEN Analysis Model Ctri Shift T TSat_Launch_Sm_4pt_groups NEU ISat Launch 5m Rod groups NEU Figure 4 9 Define groups in Femap by importing a neutral file when available 4 2 Steady State Frequency Response Analysis The following examples demonstrate Vibrata s frequency response analysis capabilities 4 2 1 Analyze 1DOF Model Using a Constant Input 1 Import the 1DOF model 1dof modes base dat Figure 4 1 and load the Nastran results Save the file as ldof modfem 2 Start Vibrata and create a new modal frequency event using that modfem file Figure 4 10 28 Vibrata Documentation Example Problems Vibrata Advanced Mod Functions Event Details EM Name Mode Set FEM Units S vraTest dof lu dof
87. ple Problems YA la M rU A pep AY per PR ToU QU oe E I Vibrata Advanced Modal Dynamic Analysis 1 0 File Functions Help JlsExporta m Evert Details Mode Set FEM Units FEM Name TEM OS aae Select S lvraTestUSatUSat sm Launch Rod modfem A_LAUNCH_RGD MODES TO 400 HZ Unch Pound f FEM aij Data for Frequency Random Analysis Variables for Custom Solvers Excitation frequency selection Log spacing at Modes St Name Value Exckation lower bound Hz 1 0 No points in range 20 ExcRation upper bound H2 1 0 No points near modes 5 b Modal Frequencies J Undamped Damped Max Response Figure 4 41 Create a new random analysis event 29 The excitation for this event is enforced acceleration in the Z direction applied at the base of the satellite Define it as follows 25 From the Excitations tab bring up the Enforced Motion dialog Figure 4 42 The only DOF available are those requested on the USET U2 card in the Nastran input file which in this case are the translations of node 6000 the independent node of the base rigid element Select Z translation for excitation and then click the t 69 button to bring up the Function Manager 26 In the Function Manager select the PSD function created above and click Done 59 Vibrata Documentation Example Problems Exckations Modal Settings Output Item Label CSys Dir Scale Factor Assign Forcing Functions to Valid DOF
88. quest only the peak value found in each element over the same time steps used for the displacements You can create the new interval definition by copying the first one and then changing the settings of the Select quantities to store toggles Figure 4 101 113 Vibrata Documentation Example Problems RFM Reaction Forces and Momelhts IP BOOM A3 FEM E S Stress in Shell Solid Elements IP BOOM A2 FEM 4 lU SINV Stress Invariants IP BOOM A1 FEM iY SVMS von Mises Stress E SMXP Max Principal Stress IP BOOM ROOT FEM F SMNP Min Principal Stress IP BOOM ASM FEM SMSH Max Shear Stress ALL_BEAMS SHYD Hydrostatic Stress PT em BUS SHELLS BEAMS FOR FORCE SHELLS FOR STRESS Contour Groups RCS PANEL SHELLS EN Shell Beam Stress Recovery Point Al Output Intervals Contour Interval set Set interval selection intent Or set specific output times First output time 1 Times and any two of Last output time gt Output interval Figure 4 101 Request peak values of von Mises stress in the RCS mounting panels 75 Solve the new contour request When the solver finishes select the new contour request in the table then click Plot Contour Figure 4 102 Vibrata will set Femap to display the results from the selected request Figure 4 103 Since we only 114 Vibrata Documentation Example Problems requested stresses for the RCS PANEL SHELLS
89. r rer ra 133 6 3 3 Fcn Vibrata function class 22 0 0 cece cece eee eee eee eee mee 133 6 4 Example SolV6et i aei Rete be nad dagar He etek ache nema to bedeln editus 133 6 4 1 Mt ALI ZATION i it eo bte Gode petet e heed Peters dei tns 133 6 4 2 Generate Modal Quantities cece cece e eee eect ee eee 133 6 4 3 Gather Event Setup for Generating Modal Quantities 133 6 4 4 Calculate Modal Quantities c cece cece eee eee rr eee teeta eee ees 133 6 4 5 Determine Output Requests cece eee cece mene 133 6 4 6 Compute Output iscri eisini ea eee ems hehe nens 133 6 4 7 Cleanup and Return sssossrrsssererrrrssrerrrrrrrererrr rr s seme meme nere 133 7 Theoretical Manual kx den eves x Ra vn e enr die seven EXTR BRN ARA 134 7 4 Normal Modes Analysis srissrssrrrsssssererrsrnerererrrrrerrr rr eme emen nenne 134 7 2 Viscous and Structural Damping s sssssssesersrssrsrrrrrrrrrrrrrrr e eee mme 134 7 3 Steady State Frequency Response AnalySiS ccceceeeeee eee eect eee eens 134 7 4 Random Response AnalySiS 0 ccceee cece ee eee eee rrrr rr rss skr menses 134 7 5 Transient Analysis ccc cece cece ee eran ene eme Seek hene sene nns 134 7 5 4 Static and Dynamic Uncertainty FaCtOrS ssissesersrssrsrrrrsrrrrrr rss rrer ra 134 7 6 Enforced Motion Excitation sssssssssseresssssererssrserersrrrrrrrrrrrr rer rr rn mee 134 7 6 1 Seismic Mass Alterna
90. re 4 33 50 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output 4 U Displacements 4 LIT Translations UTY I Uz F UR Rotations UTMAG Translation Magnitude m V Velocities VTMAG Translational Velocity Magnitude A Accelerations ATMAG Translational Acceleration Magnitude 4 TU Total Displacements 4 TUT Total Translations E TUTy TUTz 4 gt Use nodal displacement coordinate system Node Selection Nodes 2 8 15 Ex Figure 4 33 Request both flexible and total nodal X translation plots 20 Solve for the requested output by clicking Solve on the Output tab We will review these results later 21 Copy the current event and modify it to use a different forcing function 19 In the Events list select the frame FreqRsp Const event and click Copy 20 Rename the new event to frame FreqRsp Var Note that its output requests are again in black text these have not yet been solved Figure 4 34 51 Vibrata Documentation Example Problems Functions Help gt Events Name Type FEM Name gt Mew frame FreqRsp Const Modal Frequency S vraTest freme frame modfern Copy INNEN Modal Frequency S vraTest frame frame modfem T mmumumem Yt Frequency pol ATA _ import r _ Export Mode Set S vraTest frame frame modfem 2D FRAME FOR BASE EXCITATIONS Inch Poundf FEM Solver E
91. rsrssrrrrrrrrrrrrrrrrr rer erna rna 140 What s New This section describes the new features and bug fixes for each release of Vibrata Version 1 4 0 Enhancements Support FEMAP 11 2 x Warn the user in the case of a transient solution where contour outputs requested a summarized quantity such as Peak and the output time points did not encompass all of the time output points Bug Fixes Fix TIER 1666 and 1747 Corrected handling of coupled damping and highly damped modes when residual vectors are present Other minor bug fixes and enhancements Version 1 2 1 Enhancements Handle Nastran models that discard modes using effective mass threshold Improve import performance of damping matrix from Output2 files Clean up XY output record names to be more concise Change beam torque mnemonic to BTx from TQx Bug Fixes Fix TIER 1667 Other minor bug fixes and enhancements Version 1 2 0 Enhancements Support FEMAP 11 0 x and 11 1 x Bug Fixes Other minor bug fixes and enhancements Version 1 0 7 Enhancements Officially support Windows 7 Support MATLAB R2011b through R2014a Allow von Mises output for Response Spectrum solver Modified display of Response Spectrum input location to clarify the solver s operation New button on the Modal Settings tab to display the cumulative effective mass New button on the Modal Settings tab to write modal settings to a CSV file Add support for SPCFORCE results
92. ry where the log files are written If you launch Vibrata from a Command Prompt the log file will be VIBRATA LOGDIR written to the directory from where you launched Vibrata Otherwise the log file will be written to the Vibrata log subdirectory of your home directory Contains a list of directories for Vibrata to search for custom solvers The directories are separated by a VIBRATA CUSTOM PATH semicolon You can set this environment variable prior to calling the launch script Specifies whether to write debug messages to the solver log file The default is O no Set to 1 to write debug messages when you are developing a custom solver VIBRATA DEBUG ON 137 Vibrata Documentation References 9 REFERENCES 1 Wirsching P H T L Paez and K Ortiz Random Vibrations Theory and Practice Mineola New York Dover Publications 1995 2 Segalman D J et al An Efficient Method for Calculating RMS von Mises Stress in a Random Vibration Environment Journal of Sound and Vibration 230 no 2 2000 393 410 3 Rupp Cory J and Antal Gregory W Implementation Of An Efficient RMS Algorithm For Random Analysis In Vibrata Proceedings of the ASME 2012 International Design Engineering Technical Conferences amp Computers and Information in Engineering Conference August 12 15 2012 Chicago IL USA Reference DETC2012 71134 138 Vibrata Documentation Additional Output2 Data for Speci
93. s RR KK KKR RR Rea 19 3 6 3 Excitation Secho scsi oec ive Se eels ae ee ed Qi 19 3 6 4 Modal Settings Section ssssssssssssrrsrssrsrrsrsrnsrrrrsrn rn memes 19 3 6 5 INpUt CHEEKSUIN sodio tn xp Eee dee deno eate tls sedibus co plates 19 3 6 6 Output Request SCCtiOMN sssserersrssreerrrrrrerrrrrrrerrrrrrr emen 19 3 6 7 Reusing EVT Files ioc ege Re Er nee REM eben appe nee ee en 19 4 Example Problems ipee RR dg ye ER 3p t E once ek is Ix le ERR LEY ER ER ED E 20 4 4 Descriptions of Example Models cssssssssss mne 20 4 4 1 Single DOF Spring Mass Model srrmssssserersrssrrersrrrrr rss rrr rer rr eee teen eae 20 4 1 2 Two DOF Spring Mass Model ceceee eee cent ee eee mmn 20 4 1 3 Two Dimensional Frame sosreresssererssrsererrrrsrrerrrrrr rr rrr meme mene 21 4 1 4 ISat Inner Planets Exploration Satellite ssssssssssserrrrsrsererrrrnrrerrrrnr nera 22 4 1 5 Preparing the Models for Vibrata ssssrsrrsssrerrrrrrrererrrrrererrrrr ers rer enad 25 4 2 Steady State Frequency Response Analysis esses 28 4 2 1 Analyze 1DOF Model Using a Constant Input cee cceee eee eee ee ee 28 4 2 2 2DOF Frequency Response cece eee eee e eee eee memes 36 4 2 3 Frequency Response of a Frame smossrrsrrssseerrrsrrrererrrrrr mme 42 43 Random Analysis RR EE ERR cade ay vas deb ek Ye 3 AQ ees 55 4 3 1 Create Common Acceleration PSD ssssssss rer r rer eens 5
94. specify how many animation frames you want using Total outputs and let Vibrata determine the time step needed to fill the output time span with that many frames Select Responses at each time to store the results from each time step as an animation frame Click OK to create the request and return to the Output tab 129 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Output Variables Select nodal variables 4 Nodal Displacemen UR Rotations V Nodal Velocities _ A Nodal Accelerations TU Total Nodal Displacernent TV Total Nodal Velocitie TA Total Nodal Acceleratior m Contour Groups ALL NODES AND ELEMS Shell Beam Stress Recovery Point none v Output Intervals Contour Interval Set Trans Contours BB X Set interval selection intent Or set specific output times and any two of Last output time 3 0 Output interval 025 Total outputs Select quantities to store Figure 4 119 Request displacement UT contours for the first 3 seconds of the event 86 Solve the event Click the Plot XY button to view the requested nodal displacement histories These are shown in Figure 4 120 using the stacked plot mode Note the different orders of magnitude on the Y axis labels 130 Vibrata Documentation Example Problems Time Response H Displacement Node 15 UT MAG a grid none basic F Real Displacement
95. t the effective masses in Figure 4 81 this will clearly be mode 1 It is not close to any other mode so it will not be part of the in phase summation for NRC but it will be for NRL Table 4 1 Maximum response level for each summation method Summation Method ABS NRL NRC SRSS 2 083 122 76 Response 4 5 Transient Analysis The next two examples illustrate Vibrata s modal transient analysis capabilities In the first example we will simulate a thruster firing on the ISat model and in the second example we will simulate a hammer impacting the frame model 4 5 1 ISat Model with RCS Thruster Firing In this example we will use the I Sat in its deployed configuration Figure 4 6 Note that this model includes residual modes to give us improved stress results for loads applied at the RCS thrusters 67 1n Femap import the I Sat deployed model ISat Dploy Sm dat the normal modes results that go with it isat_dploy_sm op2 and the Neutral file that defines many useful groups for it ISat Dploy Sm groups neu Save the model as ISat_Dploy_Sm modfem 104 Vibrata Documentation Example Problems 68 In the Event Manager set up a new transient event and select the Femap file you just created Set the event end time to 4 0 seconds and its initial conditions to Zero Assign it an informative name See Figure 4 91 File Functions Help S wraTestNISatNSat sm Dploymodfem Mode Set FEM Uni
96. t use whatever path is actually present in your installation Obviously in order to use it your NX Nastran license must include a DMAP license Note that you can have LSEQ cards that reference different LOADSET IDs All of these load sets will be available for use in Vibrata even though only one LOADSET is referenced on the case control LOADSET card Vibrata Documentation Preparing Nastran Input files INCLUDE c apps Vibrata vibrata nx7 LOADSET 101 Additional params for Vibrata load set excitation PARAM RSOPT 1 PARAM OGEOM YES LOADSET ID from LOADSET card in case control Set ID for FORCEi PLOADi etc cards not shown LSEQ 101 1 1 LSEQ 101 2 2 LSEQ 101 3 3 Figure 2 3 NX Nastran cards including DMAP alter to enable load set excitation 2 1 4 Enforced Motion If you want to perform a frequency response random or transient analysis using enforced motion excitation you must include the highlighted statements in Figure 2 4 These statements will also enable response spectrum analysis although Section 2 1 7 describes a more direct approach for that Taken together the specified cards tell NX Nastran to compute constraint modes for the degrees of freedom specified on the USET U2 card s and to write the U2 DOF to the OP2 file so Vibrata can find them As usual all DOF listed in the U2 set must also be constrained that is they must appear on an SPCI card elsewhere in the bulk data Vibrat
97. te each license server name by a colon If you only have one server and wish to bypass the network scan by the client you can use the environment variable LSFORCEHOST You can only specify a single server with this environment variable For example you can set it to Server On Windows the environment variable can be set in the Control Panel typically in System Please ask your system administrator or refer to your operating system documentation for more details on how to set environment variables 8 2 3 Checking Your License Status You can use the RMS License Administration application WimAdmin included in the top level Vibrata directory to check the status of the licenses When the GUI opens open up Subnet Servers in the tree on the left Under each license server the individual licenses will be listed Clicking on a license will display statistics about that license including who is using it and how many are available You can also install licenses using this application Prior to using Vibrata you must contact ATA to obtain a valid license file for it To obtain a permanent license you will need to run the echoid cmd batch file that comes with the Sentinel RMS download and send the resulting echoid txt file to software ata e com If you have permissions issues running this file from the installation location you can copy the echoid files to a directory where you have write access and run it from there 8 3 Installing
98. the frame model frameO1 modes dat and its results frameO01 modes op2 Save the Femap model file as frame modfem 55 Create a new Vibrata event select the frame modfem file and create a Modal Response Spectrum event with the Summation Method set to Absolute Value Figure 4 76 90 Vibrata Documentation Example Problems WF Vibrate Advanced Modal Dynamic Analysis 101 mea File Functions Help Modal Respons S vraTest frame frame modfem Frame_RSpec_Abs mE FeMUnts Select S vraTestiframelframe modfem 2D FRAME FOR BASE EXCITATIONS Inch Poundf FEM Solver Exctations Modal Settings Output Solver Analysis Type Modal Response Spectrum Y Data for Response Spectrum Analysis Variables for Custom Solvers Name Value Figure 4 76 New response spectrum event with absolute value summation 56 Response spectra are applied as enforced motions so go to the Excitations tab and bring up the Enforced Motion Excitations dialog Figure 4 77 Note that no motion out of the XY plane is offered those degrees of freedom were removed from the model so no modes have any effective mass in those directions Select the X direction direction 1 and click the t9 button to bring up the Function Manager 91 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name Enforced Motion Excitations Assig
99. tions Modal Settings Output Stress Contour Node xY Item Label Recovery Intervals Elem xY Contour Group ALL NODES AND ELEMS none Trans_Contours Contour Group RCS PANEL SHELLS All Trans PeakStress Contour Group BUS SHELLS All Trans_PeakStress Element 5192 All Element 5193 All Element 5384 Element 5385 Element 5594 Figure 4 108 Solve the new Element XY requests and plot them 120 Vibrata Documentation Example Problems Beam Moment Element 5594 BM_ lt n2_ hoi Force Element 5594 BF_y nl C Force Element 5594 BF z nl C Tine Response Beam Moment Element 5594 TQ x nl CroundTransport RCS UnitFrc hist e 3 s ic es a Figure 4 109 Forces in IP boom connector note effects of thruster start stop 4 5 2 Frame Model Transient Animation 79 1f you have not already done so for a previous example import the frame model frameO1 modes dat into Femap and load the Nastran results Save the model file as frame modfem Figure 4 110 shows the model with notes about nodes that will be of special interest for this analysis either for defining input or for recovering physical responses 121 Vibrata Documentation Example Problems Node 15 Recover displacement history Figure 4 110 Frame model showing nodes of special interest 80 In the Event Manager set up a new transient event and select the frame s modfem file Set the event end time to 10 seconds and its initial condi
100. tions to Zero as shown in Figure 4 111 As always be sure to assign a recognizable event name 122 Vibrata Documentation Example Problems Modal Transien S vraTest frame frame modfem Frame Trms Hammer Mode Set S VvraTestiframelframe modfem Solver Exckations Modal Settings Output Solver Analysis Type Modal Transient Exact Data For Transient Analyses Variables for Custom Solvers Integration interval 2 7794e 03 Dynamic uncertainty Factor 1 0 Name Value Event end time 10 Static uncertainty factor 1 0 Initial Conditions Zero 7 Figure 4 111 Solver setup for frame model transient analysis 81 Go to the Excitations tab and create a point force load Apply the force at node 10 Use the R button to set the force direction Figure 4 112 You can screen pick the nodes from node 10 to node 9 or you can key in the labels using Femap s standard node selection dialog When you click OK on that dialog Vibrata will ask you to confirm that the displayed direction is correct Figure 4 113 123 Vibrata Documentation Example Problems Figure 4 112 Forcing function will be applied at node 10 in a direction taken from the FEM geometry 124 Vibrata Documentation Example Problems Cancel Entity Selection Select 2 Nodes for direction vector Remove by 1 Figure 4 113 Screen pick node 10 then node 9 to define the force direction
101. tive smnssssressssrererssrsererssrnererrr mme 134 Tile Residual Mectors endet uds eue rte iti ear e ah ROSE Rada 134 7 8 Response Spectrum ANalySIiS sssssserssssesersrsseserrrsrnrrrrrrrr seem menses 134 7 8 1 Absolute Summation ABS csssssseee Henne nena 134 7 8 8 Square Root Sum Square Summation SRSS sees 134 7 8 3 Naval Research Lab summation NRL csse 134 7 8 4 Nuclear Regulatory Commission Rule NRC cesceeeeeeeeeeeeeeeenes 134 8 Installation ccna tee aha eee muet ea bees Sete Se 135 8 1 Platform RequireMent ccccce cee eee ee ese em sehen hne KKR nennen 135 8 2 Installing the License Server 0 cece eee eee eect mmm 135 8 2 1 Installing Sentinel RMS ssssssssss mme 135 8 2 2 Environment VariablQ ssssssssesrrsssssrsrtrsrsen cnet ee nr rs eee nr Kr ARKA RK KAR AR RKA 135 8 2 3 Checking Your License StatUS ssssserrsrssrsrerrrssenerrrrrr sees eee rr rr rr rer eee 136 8 37 Installing Vibrata aie eire reete tesa deessent emet Peste ERA 136 8 4 Configuring Vibrata asin onaniaa Im messe hne emnes tenere nennen 136 8 4 14 Vibrata Launch SCIPt ssssssseserssssererrrsnererrrrrr mmm ene 137 9 References cui cuis t P pe n ebur ag etie su uu Me vi aie da deen BRA VAS RNA delete 138 Appendix A Additional Output2 Data for Specific ANalyS S sssssrsrsrsrrrrrrrrrrererrrrae aa 139 Appendix B Using Data from Non Nastran Solvers ssmemssesese
102. tran Input files CASE CONTROL Free Modes Small NONE EMENT PLOT ALL RT1 PLOT FIBER CORNER TRAIN SORT1 PLOT FIBER CORNER FORCE SORT1 PLOT CORNER ALL MEFFMASS NOPRINT PLOT MEFFM METHOD S Figure 2 1 TITLE card ensures that Femap creates a valid analysis set and output sets With such a TITLE card in the deck as solved Femap will create the required analysis set and will include the analysis set name in the output sets that contain its results as shown in Figure 2 2 when you import the deck and results e Jalal S Ffa k A Coordinate Systems B Geometry 3 Q Connections H Model Bes Ana ag Ma 1 FREE MODES SMALL is 2 VRA EGPM_sm_SqPulse TransComyg 1 ES 3 VRA EGPM sm SqPulse TransCon DN ge Results dE 1 Mode 1 7 38275E 5 Hz gE 2 Mode 2 5 62247E 5 Hz gE 3 Mode 3 5 08445E 5 Hz amp Entity Editor tj pa a mes Bes o General Output Set 2 H Le Tite Mode 2 5 62247E 5 Hz Value 5 62247E 5 Notes From S TestVRA gpm_sat_small op2 Date Fri May 29 16 12 18 2009 FREE MODES SMALL Title Figure 2 2 MODFEM file with required analysis set and output sets If you have already solved a large model without a TITLE card and do not wish to run it again just to add the TITLE you may be able to do so with a little careful editing in the MODFEM file Once you
103. ts jot hn e S ivraTestUSatlSat sm Dploy modfem SM DEPLOYED MODES TO 400 HZ Inch Poundf w FEM Solver Analysis Type Modal Transient Exact M Data for Transient Analyses Variables for Custom Solvers Integration interval 1 7353e 04 Dynamic uncertainty factor 1 0 Name Value Event end time 4 0 btatic uncertainty Factor 1 0 Initial Conditions Zero vi Figure 4 91 Transient event setup for deployed ISat model 69 The RCS system will fire a pulse to translate the spacecraft along its Z axis let it drift for half a second then fire a reverse pulse to stop its translation We will simulate this by applying a point force excitation at each RCS thruster node Figure 4 92 On the Excitations tab bring up the Point Force dialog Figure 4 93 Select the individual thruster nodes as shown highlight the Z direction row in the Functions table and click t 69 to bring up the Function Manager 105 Vibrata Documentation Example Problems ALIN AE as d A YA 4 aa S P mU w NL TE Figure 4 92 Nodes for RCS thruster loads 106 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name Y Point Force Excitations Forcing Functions Dir Scale Type Function Name Rx rz Ry r 3 Rz 4 m p Use nodal displacement coordinate system Node Selection Nodes Node Groups 3687 3956 Entity Selection
104. uency Hz Damping amp Figure 4 117 Set the damping of the model to 10 for mode 1 5 for mode 2 and 1 elsewhere 84 Go to the Output tab To get a measurement of the structure s movement over time create Nodal XY Plot output request for X and Y displacements UTx UTy and displacement magnitude UTMAG for node 15 as in Figure 4 118 128 Vibrata Documentation Example Problems Solver Excitations Modal Settings Output Output Stress Contour E277 Recovery Inter vals Y Nodal XY Plot Output Requests Output Variables RFIN Reaction F rce Invariant 4 U Displacements 4 UT Translations vV UTx vi UTy UTz UR Rotations 4 UTMAG Translation Magnitude V Velocities Solve Interactive Use nodal displacement coordinate system Node Selection Nodes J Node Groups Figure 4 118 Request displacement plots for node 15 85 In order to create an animation of the structure in motion create a contour request for displacement UT at all nodes Enter 0 0 for the First output time and 3 0 for the Last output time to create contours from 0 0 to 3 0 seconds We have selected 3 seconds as the end time because the structure s response will decay to about 30 of its maximum by then see Figure 4 120 Set the Output interval to 0 025 seconds and leave Total outputs blank This will produce 121 time frames for the animation Alternatively you can
105. using NRL summation 63 Copy the first event again and change the summation type to NRC 10 This should identify the same modes as closely spaced as in the NRL example above Solve this event Vibrata Documentation Example Problems File Functions Help Type FEM Name Modal Respons S wraTest frame frame modfem Frame_RSpec_SRSS Modal Respons S wraTest frame frame modfem EN F RS NRL11 Modal R SAvra Te stf Mf df rame ec odal Respons S wraTest frame frame modfern ATA Frame_RSpec_NRC Modal Respons S vraTest frame frame modfem _ Import A Export Evert Details FEM Name Mode Set FEM Units Select S vratest frame frame modfem 20 FRAME FOR BASE EXCITATIONS Inch Pound df ov FEM Solver Exckations Modal Settings Output Solver Analysis Type Modal Response Spectrum Data for Response Spectrum Analysis Variables for Custom Solvers Summation Method NRC 10 M Name Value Figure 4 85 Copy again to create a fourth event using NRC summation 64 For each event plot the results in Femap Note that Femap does not actually display contours on beam elements you will have to use criterion plots You can select that display option and also turn deformed mesh display using Femap s Post toolbar Figure 4 86 The deformation will be X translation rather than translation magnitude because the latter is not computed in response spectrum analysis Figure 4 86 Select Crit
106. ust be LogLog As always give the function a name that will help you recognize it when you want it for later use 56 Vibrata Documentation Example Problems X Spacing Start val dani End Uneven Increment 0 Function Sets 1 5 P 10 10 10 PSD Function Attributes 10 10 10 10 Name GroundTransport Figure 4 39 Create the acceleration PSD that will be used to excite the ISat 26 When all the data and attributes are set correctly click Create on the New Function dialog and save the function as shown in Figure 4 40 The new function will appear in the main Function Manager dialog ready for use in the Vibrata events you will create in the following examples Click Done to return to the Event Manager 57 Vibrata Documentation Example Problems Manage No Fiter FunctionType OrdNumDataType Nue em S anse interpolation Type Y Aus Type Figure 4 40 Create and save the function and finish by clicking Done 4 3 8 ISat with Rigid Base 27 n Femap import model ISat Launch Sm Rgd dat Figure 4 5 then import its results isat launch sm rgd op2 and the neutral file containing its groups ISat Launch Sm Rgd groups neu Save as ISat sm Launch Rgd modfem 28 Start a new event using that FEM Set the Solver Analysis Type to Modal Random Be sure to enter a recognizable event name Figure 4 41 58 Vibrata Documentation Exam
107. ut Requests sssssssersesressusseesrosrerrorrsorrunrennusrunrnuruen 18 3 2 Event Manager Batch Solution Mode csssssss mm 18 3 2 1 Batch Processing with MATLAB SCrIPtS ssssssssssssserrerrrrnererrrrnrrerr rr erna 18 3 3 Function MAN QQ Class ssd iie Seed ee ea ex yan cay da weed MR ER e Dye eR Pen GE 18 3 3 1 Functions REGION Hasena eher rer reset leg eue dunt vele eret epa dat 18 3 8 2 Function Sets REGION is sana nd rotten cece ence ee eee eee nee menses enn 18 3 3 3 PlOE REGION rero caster desea ped e evade da an le ele ee ee 18 3 3 4 Math REGION iaman ab ara netu pH se thal des SR Nn Aa DEAR 18 3 8 5 Hints for Creating Complex Functions sese 18 3 4 XY Plot Results Display 0 cece eect eee ee eee I I hh 19 3 5 Contour Results Display sssssssssrsssssrsrrssssrnersrrnrnrrsrrn memes ess en eene 19 3 5 1 Viewing Transient Analysis Results sssssssssserrrrssserersrrsererrrrrr rer r rr rr nara 19 3 5 2 Viewing Frequency Response Results stossssssrerssssrrrrrrrrrerrrrrrner ers renar a 19 3 5 8 Viewing Random Analysis Results srsssssrrssesrrrrrrrrrrerrrrrrrerrrrr rr re rr renad 19 3 5 4 Viewing Response Spectrum Results cece cece eee eect ee rr reser enad 19 3 6 Event Definition File EVT s eie Penida ee trc e P Te eeud a ebd Ra Er 19 3 6 1 Event File Conventions ssssossessessrssrrrrrrrrrr Ihnen 19 3 6 2 Event Summary Section cece een eee teeta ease
108. xcitations fen Figure 4 115 Save the new function to the frame excitations file Exctations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name E Point Force 1 Force Node 10 basic 1 0 96723 Hammerfrc Unit TnPulse Load Set 2 Force Node 10 basic 2 0 2539 Hammerfrc Unit TriPulse Enforced Motion Forcing Functions Dir Scale Type Function Name F x 0 96723 Force HammerFrc Unit TriPulse S Y 0 25390 Force HammerFrc Unit TrPulse S fe m Use nodal displacement coordinate system Node Selection EC Self correlated Figure 4 116 Apply the forcing function to the Vibrata event 83 Go to the Modal Settings tab and open the damping dialog Use the damping schedule to set the viscous damping to 1 for all modes then key in damping of 10 for mode 1 and 5 for mode 2 as in Figure 4 117 127 Vibrata Documentation Example Problems Solver Exckatons Modal Settings Output Frequency Modal Damping 96 Translational Modal Effecti a Mode Hz Viscous Structural 1 0160 10 00 0 00 3 1440 5 00 0 00 Effective mass threshold 96 Modal Viscous Damping Sum mar y User Matrix Mode Frequency Schedule Diagonal Off Diagonal Ratio Diagonal Hz 95 Mean Max 1 0160 10 5 4201 1 00 7 4740 100 11 1395 1 00 15 4939 1 00 15 5820 1 00 31 4804 1 00 O A VI 4 ww NA KK rA e No 1 2 3 4 5 6 7 8 Viscous Damping Schedule Freq
109. xckations Modal Settings Output M Stress Contour Item Label Recovery Intervals Elem XY 2 CSD 8 15 Plot XY Plot Contour Figure 4 34 Use the Copy button to create a new event from an existing one 21 With the new event selected go to the Excitations tab delete the existing excitation and define a new one using the variable amplitude forcing function Figure 4 35 52 Vibrata Documentation Example Problems Vibrata Advanced Modal Dynamic Analysis 1 0 7 jee roe x File Functions Help Events Name Type FEM Name LN lt e a ATA Evert Detals FEM Name Mode Set FEM Units Select S lvraTestlframelfraeme modfem 2D FRAME FOR BASE EXCITATIONS Inch Poundf w FEM Solver Exctations Modal Settings Output Soler ExcRations Modal Settings Output Type Item Label CSys Dir Scale Factor Function Name 1 Accel Motion 2 disp 1 1 0 Var 1to3g 1to40Hz Figure 4 35 For the new copied event delete the old excitation and create a new one 22 Solve the new event by clicking Solve on the Output tab 23 Compare the results of the two events 22 On the Output tab click Plot XY after the solution has finished 23 In the UIPlot dialog load the results from the first frame event Figure 4 36 53 Vibrata Documentation Example Problems File f Plot Options Statistics L Load Workspace n Save File Save Workspace

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