VPG34_NISA_Modeling_..
Contents
1. Element Stiffness Matrices fog 30 x l File 25 Element Damping Matrices p SSS SSW File 26 gt Model Analysis And Restart Data v M Inertia Relief Calculation r Execution Blank Common Limit For Input Pha Go v 50000 Number Of Max Stresses To Be Sorted Element Reseguence FileSize For Decomposed Stiffiness 25 on x oan Altered Matrices Filenames Model Geometric Properties 7 Node Echo Stiffiness Matrices Com ute And Print x MV Element Echo Mass Matrices fo M Auto Constraint Warning TES Damping Matrices M Go Memory 10000000 l Stop OK Cancel OK Cancel Page 19 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial Users wishing to know more about these options are asked to view the NISA User Manual that is packaged with the eta VPG software By selecting the RUN NISA option upon selecting the OK the VPG then opens a NISA execution window and executed the NISA simulation The POST Menu The model results can be viewed in the POST menu This allows the user to review and animate the deformations of the model review and display stresses for the model and generate graphs contour plots and avi animation files of the RATTE model results Print Print To File Select POST from the top menu bar in VPG This will open the post processing module To review the results the user must read in the results files2. and the associated model file used to generate these results To review our analysis go to FILE and select the OPEN option The user will see a FILE OPEN window The file type should be set to NISA2 dat VPG will search for the results file file 26 in NISA terminology Select File Look in Ea H lin_stat26 dat File Name Open File Type NISA2 Post dat TE aa After the file is opened in VPG the user will automatically be placed into the Displacement animation menu The model will be displayed in a wireframe mode the shaded with element edge option is shown below Page 20 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial The user may animate the results by selecting the load case and then the Play button In our case we have only one load case to choose We can also select the Undeformed option which will display the original shape of the model The deformation can be exaggerated on the display by changing the Scale value By default the value is 1 0 for our example setting the scale value to 10 0 will result in a display as shown below To view the results in the form of a contour plot we can select the CONTOUR icon from the top menu bar dal Users may select the Contour Plot Animation value to display either displacements or stresses in a contour mode All available quantities which may be displayed in a contour plot are found in the Component drop down menu TO view
3. and the meshing process will begin A preview of the mesh will be shown in a white color To generate this mesh the user should select ACCEPT The final mesh should look like the figure below While we do not need a rigid link in our example model it is useful to describe the method to create one In the ELEMENT OPTION menu the user selects the CREATE function A menu showing all NISA element types supported in VPG is displayed The element type used for a rigid link is RLINK The user must define the degrees of freedom which will be constrained from the master node to the slave node s When the nodes for the RLINK have been selected the user selects DONE and the rigid link is displayed Page 11 of 22 ELEMENT TYPE THICK SHELL Select ne From The Following F i Belle LL 0 0 F SOLID SPRING DAMPER sY Symmetry _ sY Anti Symmetry MASS Z Symmetry _ z Anti Symmetry PLOTEL f aie 2 Symmetry _ 2 Anti Symmetry CABLE Select Any Combination From Following PIPE ELBOW __ Translation __ Rotation LINK Translation Rotation SPAR zl E RLINK amp _ ZTranslation __ ZRotation MPC CPD ps OK EXIT NISA Modeling Tutorial VPG Pre Post Tutorial The NODE Menu NODE OPTIONS The mesh has been created but since it was created in several individual steps there are duplicate nodes on the ALIGN NODES NODE BETWEEN PT NODE EE i CHECK DUPLICATE ID boundaries of the
4. meshes we created To PRE PROCESSOR COINCIDENT CHECKE identify and repair this condition we will COPY enter the NODE menu Ee is rl SURFACE NODES To identify this condition select NODE SORME IDENTIFY NODE POINT OPTIONS from the main menu The NODE o function to check this condition is the MODEL CHECKER SS O COINCIDENT CHECK select this menu SET MENU PROJECT option VPG will prompt the user for the MATERIAL RENUMBER NODES tolerance it will use to check if nodes are ELEMENT PROPERTY ae 3 i Se ooo TRANSFORM coincident This should be a number small BOUNDARY CONDITIONS T in comparison to the element size Since NISA MISC CIRCLE CENTER Ct our element size was 0 75 enter 0 05 into Ear VIEW the prompt area MMMM VPG will identify and highlight any nodes which are within this distance resultant from one another In order to repair this condition nodes must be merged and the elements redefined using these nodes This is done automatically using this function EIT MODE VPG will then offer options for repairing this condition COINCIDENT CHECK B The user may select specific nodes to merge displayed ENTER TOL DEFAULT 0 01 nodes or all identified nodes Nodes will be moved Gos slightly during this operation so VPG offers an option for the certain nodes to be retained or for the central position of the nodes to be used as the new location Select the ALL NODES option and the MIDDLE POSITION option for our examp
5. subcase definitions Please enter 1 accept default for the SPDISP SET number Page 14 of 22 NISA Modeling Tutorial SPOISP SELECT OPTION CREATE ENTER SPOISP SET NUMBER 1 OR 1 TO EXIT VPG will then open a window which allows the user to define the degrees of freedom which will be associated with this SPDISP set For our example we will fully constrain all of the nodes around the hole therefore we will select the ALL D O F option as shown in the figure The SPDISP is an enforced displacement This means it can have a zero value where it is a constraint and a non zero value where it enforces a specified displacement in the degree of freedoms the user defined In our case VPG will prompt the user for the displacement value which will be 0 0 1 DEFINE O0 O F FOR SPOISF D O F 123456 S FIXED ENTER ENFORCED DISPLACEMENT DEFAULT Is 0 0 VPG Pre Post Tutorial Select One From The Following CHL p oF _ XY Symmetry sY Anti Symmetry vZ Symmetry _ YZ Anti Symmetry 2 Symmetry 2 Anti Symmetry Select Any Combination From Following __ Translatian __ Rotation __ Translation __ Rotation __ 2tTranslation __ 2Rotation S95 gt gt gt JK Cancel The user can now select the node s that are to be constrained We will select each of the nodes around the hole To do this drag a window around the nodes and release the mouse button When all of the desired nodes are highlighted select S
6. to the displayed parts using the colors of the text in the material list To assign the material we just created select ASSIGN MATERIAL Select the material name that was created in the previous step and then select the part of our bar model When the material is assigned the part color will change from a white to the material color red indicating that the material assignment is completed Please EXIT from this menu for our next step in creating the NISA model The BOUNDARY CONDITIONS Menu Loads pressures constraints and enforced displacements are defined in the BOUNDARY CONDITIONS menu This menu allows users to define edit and apply these types of boundary conditions on their models NISA provides many different types of constraints and loading options for the user We will demonstrate the application of a constraint around the hole in our bar and a force applied to the nodes at the end of our bar model To define the constraints around the hole we enter the BOUNDARY CONDITIONS menu selecting the SPDISP sub menu _ lt lt _ _ _ _ PRE PROCESSOR LINE SELECTION OPTION SURFACE EE mae MODE DELETE MODEL CHECKER Ea INCLUDE NODES IN SET MATERIAL BOUNDARY CONDITIONS List SET ELEMENT PROPERTY MODIFY BOUNDARY CONDITIONS LOAD REMOVE NODES IN SET MISA MISC SPOISP it GHO E EXIT EXIT VPG will allow the user to create the constraints as a set which can be identified in the
7. we will create the geometry and then create a mesh on that geometry data NISA models typically do not have a part concept meaning that the element types and properties are not grouped or assigned by part definitions They are controlled by the element definitions However for VPG users the concept of parts is very normal and a convenient way to manipulate the model data Page 7 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial When a part is created in VPG it is necessary to create is using an element type NKTP in NISA terms This identifies that the elements are beams solids shells etc VPG will not allow the user to mix the element types within a part lf a part will contain only geometry it is not necessary to set the NKTP ELEMENT TYPE ID or MID MATERIAL ID parameters PART DEFINITION PART DEFINITION PART ee Figure 2 CARD DESCRIPTION i VPG Main Menu and PID PART ID DTM Menu Location NKTP ELEMENT TYPE ID MID MATERIAL ID off Cancel The FILE Menu The FILE menu provides the user access to functions which save restart import and export models The function that we will access is the IMPORT function Under this function the user can import CAD data or finite element model formats There are native CAD interfaces for commercial CAD software and industry standard interfaces such as IGES and STEP formats lf a commercial CAD interface is chosen VPG will open a DOS window which
8. 1 ELEMENT STRESS PRINTOUT KEY 5 LQ2 AVERAGED NODAL STRESS PRINTOUT KEY l4 KELFR ELEMENT STRAIN ENERGY OR INTERNAL FOR TSFRE INITIAL TEMPERATURE o c00000E 000 TOL TOLERANCE FOR NODE POINT FORCE UNBALANC o c00000E 000 KSTR ELEMENT STRESS CACULATION KEY fT i KRCTN REACTION FORCE CACULATION KEY fi La COORDINATE SYSTEM KEY FOR DISPLACEMENT 2 3 e KSTN ELEMENT CENTROIDAL STRAIN CACULATION K Cancel MEX Previous Cancel The user can type the load case description linear_static in the LCTITLE DESCRIPTION field No other control cards are required for the execution of our example model The ANALYSIS Menu The ANALYSIS menu allows the user to control the simulation output solution type and memory used in the solution The output files that are created will have the name of the NISA nis file by default The user may override this by entering a new name into the OUTPUT FILE NAME field of Page 1 of the ANALYSIS SUBMISSION menu For your convenience please accept all of the default values on Page 1 and Page 2 of these menus ANALYSIS SUBMISSION ANALYSIS SUBMISSION Pagel Page2 ANALYSIS TYPE STATIC x ERUN NISA Solver Type Restart Options OUTPUT FILE NAME ftemp l EXPORT nis Frontal Solver x set Fresh Run x Size of RAM in MB available to Sparse _ File 22 Reaction Coeffecients _ Print Restart Info x File 23 Element Mass Geometric Stiffness Matr File 24
9. NDARY DISPLAY JE MODELCHECKER TaecwanalE Bei ideale CHECK OVERLAP pulse an ancora Ze ee ehecm NORMAL BOUNDARY CONDITIONS CHECK RIGID LINK CHECK ELEM SIZE CHECK SKEW MISA MISC EXIT Since we have already repaired the coincident nodes the model has no boundary problems and is ready for execution The NISA MISC Menu Now that the model has been created and checked the user needs to define what output is needed and how exactly the simulation is run This is accomplished by the use of Control Cards The definition of Control Cards is performed through the NISA MISC menu accessed from the PRE menu CONTROL CARDS Forces Moments and other boundary Sen conditions can be selected for use in a LOAD sala CASE LDCASE By default all loads forces a moments pressures and constraints will be NISA MISC used in the simulation a o MODEOUT Note f users desire to create additional MATDIR sae eur loading cases or need to use a subset of the PDAMPING oa forces and constraints in the model they may VECTOR SEDCOMP use the GROUP card to define groups of loads CONTROL CARDS STRSFILTER and constraints TITLE PRINTCNTL EXIT EXIT Page 18 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial LDCASE DEFINITION LDCASE DEFINITION LDCASE DEFINITION CARD LDCASE DEFINITION CARD 2 LDCASE LDCASE ITEMS ITEMS LCTITLE DESCRIPTION liinear_static LCTITLE DESCRIPTION liinear_static IDLDCASE LOADCASE IDENTIFICATION NUMBER L
10. VPG PrePost Tutorial VPG PrePost Tutorial NISA Modeling Execution and Post Processing Release Date April 2009 VPG PrePost Tutorial Engineering Technology Associates Inc assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein Engineering Technology Associates Inc ETA the ETA logo and eta VPG are the registered trademarks of Engineering Technology Associates Inc All other trademarks or names are the property of their respective owners Copyright 1998 2009 Engineering Technology Associates Inc All rights reserved Engineering Technology Associates Inc 1133 E Maple Suite 200 Troy Michigan 48083 USA Phone 248 729 3010 Fax 248 729 3020 Support email support eta com Page 2 of 22 NISA Modeling Tutorial VPG PrePost Tutorial VPG PrePost Tutorial This tutorial was created to familiarize eta VPG users with the functions and techniques associated with the use of the construction preparation execution and post processing of NISA models within the VPG user environment This tutorial will demonstrate the steps required to properly prepare a model for simulation using NISA finite element software from within VPG Background Information Graphic User Interface The graphic user interface consists of 6 areas within a single window Main Menu Drawing Window View Options Dialog Window and Display Options and
11. automeshing menu in VPG and allows the user to generate mesh on complex surface data with minimal repair begh Definition ELEMENT OPTION ONORE HOLE size Jood MERGE BOUNDARY GAP COARSE ELEMENT pE Sisire ae eee ELEMENT BITE p75 REVERSE NORMAL CHANGE ID er eee zom SURFACE MESH Mi checksursces _JPrevew Boundary FT _ Ship Narow Surfaces Modify Boundary Nodes CREATE y E Fave inawr Hotes Aio Repair DELETE TOPOLOGY MESH P in Original Part CE jeh by Part DRAG MESH o TRIANGULAR MESH _ Local Re mesh _ Variable best ELEMENT TYPE EXIT _ in Points Mesh _Ja dd Washer p eee Mash Quality IDENTIFY ELEMENT es E LABEL rarer oso MIRROR ASPECTRATIO Booo o MODIFY TRA MINT ANGLE 1500 LINE MESH TRIA MAX INT ANGLE E PENUMBER QUAD MIN INT ANGLE i GUAD MAK INT ANGLE 180 MIN ELEM SIZE 5 oo SPLIT MAX ELEM SZE 25 00 SURFACE MESH K AUTO REPAIR The user should select ELEMENT SURFACE MESH and then TOPOLOGY MESH to enter the automeshing panel The Mesh size and quality parameters are defined using the fields provided For our example we need to generate elements which are 0 75 units in size The other default parameters are acceptable for this type of model The user should select the surface of the geometry data by either selecting it with the mouse or by selecting the PART from the menu Page 10 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial When the surface has been highlighted select DONE
12. e the user has some idea about e Model geometry e Material properties and Thicknesses of the model parts e Type of output required from the analysis Start VPG and create a new database Enter bar vpg as the database name SETUP DEFAULTS VPG will prompt create a new database select Program Display YES ANALYSIS PROGRAM M i TASTEAN VPG will ask the user to select a database type mE KE defining the solver which will be used in the ees E simulation Select NISA from the SELECY E MOLDFLOW ANALYSIS menu to set the element types materials PAMCRASH eh i _ CORNER BIAS MESF papjoss and boundary conditions to those available in NISA _JEDGE BIAs MESH GENESIS NASTRAN S70 In the empty database we will import some AUTOMATIC BACKUF WISA Element Type Display 51 geometry define elements materials boundary _ ALL ELEMENT ONIOFF _ REVERSE ELEMENT conditions and control parameters The first step in creating a FE model with VPG is to create a PART entity Parts can contain geometry or elements They don t need to be representative of any physical entity For instance you might have some geometry and some elements of your model in a part not necessarily all elements or geometry of a physical structure Parts are a way for users to conveniently group data in their model However most users will group the data in parts as a complete physical structure geometry and or elements Since we have no geometry to import
13. eu DONE from the menu ABORT EXCLUDE ON OFF The selected nodes will then be KEY IN NODE RANGE identified with an ALL note MULTLPOINT REGION confirming that these nodes will NODE be constrained in ALL degrees of PART freedom WINDOW FREE REGION Forces can be applied in much CIRCULAR REGION the same manner Exiting to the REJECT LAST BOUNDARY CONDITIONS DONE menu we will select LOAD from the menu The user will be presented with all of the various options to load the model including point forces moments and pressure loads For our example we will select FORCE MOMENT Page 15 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial LOAD CARDS SELECTION OPTION BEAM LOADS BODY FORCE val 7 a FORCE MOMENT CREAT EOGEFORCE DELETE PREUR master LIST FORCE BOUNDARY CONDITIONS MOVINGLOAD MODIFY movnceath o ono he Ce CIOS FOIRSIE rs NODAL TEMP DIFF SPDISP fj Eo E After selecting FORCE MOMENT the user can then edit or delete existing forces or create new ones Select CREATE from this menu and we will define nodal forces for our example As with the constraints we can define a set by which to reference a series of loads We will enter 1 for this set number default value defined b VPG FORCE MOMENT SELECT OF TION CREATE ENTER CFORCE SET NUMBER 1 OR 1 TO EXIT AR oae VPG will then ask us for a nodal force value Enter the value 0 0 0 25 to define a force acting in the Z di
14. l may make use of optional display features including background colors shading and element outlines These may be controlled through the UTILITY Menu and the SETUP options found there Page 4 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial Introduction The NISA suite of software has been in use by engineers and scientists since the 1980 s when Engineering Mechanics Research Corporation EMRC first commercialized the product Users worldwide have used the NISA solver for automotive aerospace civil structural problems taking advantage of the efficient data structure and accurate solution The NISA solver has been made available through an add on module in the eta VPG software product Static linear and normal modes solutions may be created and executed through the eta VPG user interface This capability allows the user to perform stress and deflection calculations on their structure and the ability to calculate natural frequencies of their structures using this simple interface The goal of this tutorial is to instruct the user in the method of creating executing and post processing a NISA simulation In order to automate this process a Drop Test Module has been implemented in eta VPG that allows the engineer to quickly define all necessary parameters used in a drop test and by allowing the engineer to create a series of drop test simulations representing multiple test configurations Problem Description For our examp
15. le COIHCIDEHT WODE CHECE OFTION NODE CHOICES iv T A EEN erek LOWER ID HIGHER ID MERGE ONLY OK Feset Cancel EMIT VPG will then prompt if you would like to merge and delete the now unused nodes or if you would like to merge the nodes and retain the now unused nodes For our example we will select MERGE and DELETE Page 12 of 22 NISA Modeling Tutorial The MATERIAL Menu VPG Pre Post Tutorial The definition of model materials and the assignment of the materials to model parts is accomplished through the MATERIAL menu MATERIAL DEFINITION MATERIAL DEFINITION CARD 1 Mi MATERIAL MATERIAL PROPERTY ITEMS DATA ASSIGN MATERIAL CARD DESCRIPTION MATERIAL_1 CHANGE COLOR MATID MATERIAL ID fi COPY HISA HATEEIAL BODELS lt a EX ELASTIC MODULI IN X DIRECTION CREATE m EY ELASTIC MODULI IN Y DIRECTION o c00000E 000 DELETE TEREE 1 1 HATERTAL EZ ELASTIC MODULI IN Z DIRECTION o c00000E 000 LIST 741 ogy cee NUXZ POISSON S RATIOS IN Y DIRECTION o c00000E 000 MATERIAL COLOR ON OFF NUYZ POISSON S RATIOS IN Z DIRECTION o c00000E 000 lt 4_ 1 APLASTIC ON OFF RENUMBER 5 1 CREEP VIEW A EXIT EXIT OK Next Cancel When the user enters the MATERIAL menu the model display will be indexed to the materials defined in the database The part colors will correspond to the part colors shown on the PART ON OFF menu If a part is displayed in a white color it is a
16. le problem we ll choose a simple structure that will allow use to define some simple geometry some easily created boundary conditions and material properties The geometry of our example is shown below The bracket Is fixed around the hole Load is added at the end of bracket A A Material properties are as following w S o be f a a e Isotropic w Pa N an e Young s Modulus 3 0E 07 psi P i ee A No Nor e Poisson s Ratio 0 3 ASe e a L M hs F s w d os i i S ce i M Page 5 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial Procedural Flowchart Open VPG and set database type to NISA Import CAD data or create geometry in eta VPG Create PARTS using the proper element type Create Mesh using VPG meshing tools Define Material Models and Shell Thickness Define Boundary Conditions and Loads Define Simulation Parameters and Output Files Output Model for Calculation Page 6 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial Creating a NISA Model For our example we will create geometry and construct a model for a static linear analysis To start our example open a new VPG database When you open the new database select NISA from the Main Menu Optionally this can be selected from the SETUP menu in the ANALYSIS PROGRAM menu selection Selecting NISA will allow you to begin to define all of the parameters necessary for a static linear analysis model It is expected that prior to entering the VPG softwar
17. n indication that no material properties have been assigned to that part To create a new material for our model we will select CREATE from the MATERIAL PROPERTY menu This will open a list of available material types Since our simulation is a simple static linear analysis and our material is an isotropic steel we will select the MATERIAL option from the list To define the specific material constants associated with our material VPG provides a table to enter these properties Please be MATERIAL COLOR ON OFF MATERIAL PROPERTY ASSIGN TOTE all CHANGE COLOR COPY CPEATE DELETE DEFINE PROPERTIES ERASE UNREF MATL LIST FEG Benu Tindor NE MAT NAME MID 1 MATERIAL RENUMBER VIEW EXIT sure to enter properties which correspond to you model units The minimum data required is an Elastic Modulus and a Poisson s Ratio for the material For our material steel we will enter 3e7 in the EX ELASTIC MODULUS field and 0 3 in the NUXY POISSON S RATIO IN X DIRECTION When the data has been entered select OK to accept the data and create the material Page 13 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial Once the material has been created we may assign it to any parts in our mode which contain elements To apply this material to our bar model we will select ASSIGN MATERIAL from the MATERIAL PROPERTY menu A list of available materials will be displayed in the menu area and will be referenced
18. of the hole as shown in the figure below PRE PROCESSOR LINE SURFACE ELEMENT NODE MODEL CHECKER SET MENU MATERIAL ELEMENT PROPERTY BOUNDARY CONDITIONS MISA MISC EXIT ELEMENT OPTION COARSE ELEMENT CHANGE ID COPY i CREATE BELETE DRAG MESH ELEMENT TYPE IDENTIFY ELEMENT LABEL MIRROR MODIFY LINE MESH RENUMBER REVERSE NORMAL SPLIT SURFACE MESH AUTO REPAIR 2 LINE MESH 3 LINE MESH VPG will prompt the user for the number of elements to be generated The first value is that along the lines selected the second number is the number of elements to be generated between the selected lines NG PICK LINE PICK LINE ENTER NWO OF ELEMENTS ON EACH SIDE N1 N2 No Nea aA Enter 4 2 generating 4 elements along the selected lines and 2 elements between the selected lines The resulting mesh is shown in the figure below To accept the mesh the user selects YES from the menu when prompted to accept the mesh If the user would like to abort or remesh the model they may select those options and restart the meshing operation Page 9 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial To complete the mesh around the hole the user can the model as shown in the following figure To create the remaining mesh we will use an automeshing tool which creates meshes on a surface This is found in the ELEMENT menus under the SURFACE MESH menu The TOPOLOGY MESH is the
19. oper number of MODEL CHECKER fields on subsequent Cards in the SET MENU SELECT OPTION RCTABLE definition For our case we will matema o enter 8 in this field providing fields for 8 ELement pRopeRTy EAM constants on CARD2 Enter 0 1 for each BOUNDARY CONDITIONS sane of the fields on the card inthe RCx fields Wsamec POME coo E se UREILE ial aaes caRD1 x RCTABLE o ITEMS DATA ITEMS CARD DESCRIPTION CARD DESCRIPTION IDRC REAL CONSTANT ID no E NUMRC NUMBER OF REAL CONSTANT RC2 REAL CONSTANT2 Be Mee eee RC3 REAL CONSTANT3 RC4 REAL CONSTANT4 RC5 REAL CONSTANTS RC6 REAL CONSTANTS RC REAL CONSTANT RC8 REAL CONSTANTS OK Next rat Cancel OK Pai ext Previous Cancel As in the material definition we can then ASSIGN this RCTABLE to the parts we desire Exit to the Main Menu The MODEL CHECK Menu After the mesh has been generated materials defined and boundary conditions created for the model it is important to check the model for common errors All of the model checking and repair functions are found in the MODEL CHECKER menu Page 17 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial Select BOUNDARY DISPLAY from the MODEL CHECKER menu to display the free edges of the model This allows the user to determine if there are any unwanted voids or cracks in the model PRE PROCESSOR MODEL CHECKE SELECT OPTION LINE SURFACE SINGLE ee ELEMENT aspect Ratio MULTIPLE SURFACE NODE BOU
20. rection with a magnitude of 2 5 N ENTER TIME AMPLITUDE CURE ID ENTER NODAL FORCE Fe FY Fa ME hy MZ OR The user may select the nodes on which they would like this force applied to Select eh three nodes on the free end of the bar as shown in the image Once the nodes have been selected the user selects DONE from the menu to complete the selection An arrow is displayed indicating the direction and locations of the forces ETA Pent Page 16 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial The ELEMENT PROPERTY Menu NISA models make use of a general purpose RCTABLE real constant table for definition of various model quantities One of the applications of this RCTABLE is the definition of material thickness NISA allows the definition of material thickness at each node of an element and uses the fields on an RCTABLE definition to define the material thickness Our model has a uniform thickness of 1 0 mm We will define an RCTABLE with just four numbers 1 0 1 0 1 0 1 0 denoting a material thickness of 1 0 To define the RCTABLE we enter the NISA MISC menu and select the ELEMENT menu and then the RCTABLE option This will open a dialog for creation of an RCTABLE ee ee OO PRE PROCESSOR After selecting CREATE from the LINE RCTABLE menu the user will define an EREE RCTABLE name and the number of TEN constants that will be used in the table Tane This will provide the pr
21. the Top Menu Area TOP MENU BAR File Parts Pre Road SUSp Utmies View ALE FS DTM Macro Help NSS ad GAIAAFS DPA Esa VHA J HGF ar amp VIEW OPTIONS DRAWING WINDOW Z He y ETA YPG READING LOAD CURVE DATA CURRENT RI RESET CURRENT UNIT SYSTEM MM TON SEC N DATABASE RESTORE M LINES T SHRINK T FILLHIDE ENTER COMMAND M SURFACES NORMAL COLOR DI ALOG WI NDOW ZELEM OREN SHADE DI SPLAY OPTI ONS Lal Figure 1 VPG User Interface 1 MAIN MENU The Main menu options are displayed in this area after selections from the TOP MENU BAR 2 DRAWING WINDOW Display graphic entities CAD points lines surfaces FEA nodes elements 3 VIEW OPTIONS Page 3 of 22 NISA Modeling Tutorial VPG PrePost Tutorial Part control model positioning program setup and utilities 4 DIALOG AREA Interface command prompt and scrollable command history 5 DISPLAY OPTIONS Toggle ON OFF graphic entities to be displayed and controls display mode 6 TOP MENU BAR This menu lists all of the main menus as well as Utility menus and Help Menus Function Keys For quick access and to improve productivity function keys are assigned for the most frequently used menus as follow Aa _ FPR F3 Fa F5 F6 Clear Menu Element Import File Model Options Options Checker Options E S eet Seo Surface Pre Online Help Options Processor NOTE Please note that some images shown in this tutoria
22. the Z Displacement contour set the Contour Plot Animation value to DISPLACEMENT and set the COMPONENT value to Z Displacement The display will show the image below Page 21 of 22 NISA Modeling Tutorial VPG Pre Post Tutorial The contour bar at the right of the display will show the maximum and minimum values of the displacement To display the Von Mises Stress contour set the Contour Plot Animation value to STRESS STRAIN All stress values available will be listed in the COMPONENT drop down Select VON MISES and select the TOP surface from the LAYER drop down The contour plot below will be displayed When the user has completed the post processing tasks they may QUIT the post processing tools and return to the pre processing tasks Summary Static linear analysis can be performed using the NISA solver executed from VPG All of the modeling tasks associated with building a NISA model can be accessed within VPG You can get additional information by contacting support eta com Page 22 of 22 NISA Modeling Tutorial
23. will display the results of the import of the data and report the successful import or any errors which may have occurred For our case we import the geometry of the bar in IGES format We will select the FILE menu from the upper left hand corner of the VPG window and select the IMPORT command The File Open window will appear and the user should select We will select the IGES file type from the window drop down menu and select bar igs from our VPG_Tutorials PREPOST NISA directory After the file is imported the user will be able to review any import related messages in the message area at the bottom of the VPG window This model now contains the geometry surfaces and lines necessary to construct our finite element model Page 8 of 22 NISA Modeling Tutorial The ELEMENT Menu VPG Pre Post Tutorial Creating NISA elements in VPG is accomplished through various means Elements may be created one at a time or for the entire model using the line and surface data All element creation tools are found in the ELEMENT menu For our example we will use a semi automatic method for creating elements CREATE allows users to define one element at a time We will use the 2 LINE MESH function where we define 2 lines between which we would like to create a mesh VPG will automatically generate multiple elements between the lines selected using a number of elements defined by the user Select the lines near the hole and a segment
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