workbench动力学分析实例.ppt

Workshop2SimulatetheCrushingofanEmptySodaCan WorkshopGoalandProcedure Goal Crushanaluminumbeveragecanandallowitto springback Procedure CreateanExplicitDynamics ANSYS AnalysisSystemProjectSelecttheunitssystemanddefinethematerialpropertiesImport modify andmeshthesodacangeometryDefineanalysissettings boundaryconditions andexternalloadsInitiatethesolution AUTODYN STR andreviewtheresults Step1 CreatetheProjectSchematic StartANSYSWorkbenchandfollowthesequencedstepsusingtheabbreviationsshownbelow DC DoubleClickwithLeftMouseButtonSC SingleClickwithLeftMouseButtonRMB RightMouseButtonSelectionD D DragandDrop HoldLeftMouseButtondownonitemwhiledraggingittonewlocationandthenreleaseit i e CopyorMove DC 1 CreateanANSYSExplicitDynamicsAnalysisSystemProject Step2 SpecifytheProjectUnits 2 aSelectMKSfortheProjectUnitsfromtheUnitsListprovided2 bRequestthatNativeApplicationsinWorkbenchhavetheirvaluesbeDisplayedintheProjectUnits2 cCheckthoseunitsystemstoSuppressfromappearingintheUnitsList Note EngineeringDataisnativeinWorkbench butMechanicalisNOTatthistime butwillbeinthefuture Step3 DefineEngineeringDataMaterial 3 aEdittheEngineeringDatacelltoaddamaterialtothedefaultlibrary 3 bSelectthelastslotunderEngineeringDatatodefineanewmaterialmodel SC 3 cEntermaterialmodelname My Aluminum Note AnexistingmaterialmodelintheExplicitMaterialslibrarycouldhavebeenselected buttherearerestrictionsonelementtypesthatcanbeusedwithcertainmaterialmodels whichwillbediscussedlater DC DC DC DC Step3 DefineEngineeringDataMaterial SC 3 eAddthefollowingPhysicalPropertiestothematerialdefinition DensityIsotropicElasticityBilinearIsotropicHardening 3 dMakesurethenewmaterialisactiveinordertodefineitsproperties Step3 DefineEngineeringDataMaterial 3 fEnterthefollowingvalues Density 2710kgm 3Young sModulus 7e10PaPoisson sRatio 0 30YieldStrength 2 9e8PaTangentModulus 0 0PaSincethematerialissufficientlydefined thebluequestionmarksandyellowfieldsarenolongerpresentinthedatatable Note Theresultingstress straincurveiselastic perfectlyplastic Nostrainhardeningcandevelop Step3 DefineEngineeringDataMaterial 3 gReturntotheProjectSchematic3 hSavetheProjectbyselectingthe SaveAs iconandBrowsetothedirectoryindicatedbyyourinstructor Usethename empty soda can fortheProjectname Note SavingtheProjectsavesalloftheimportantfiles TheProjectmayalsobeArchived inwhichallofthesupportingfilesarecompressedandsavedinonefile Step4 ImportandModifytheGeometry 4 cWorkbenchhasnowidentifiedthegeometryfile notegreencheckmarkinGeometrycell ItisnowOKtoDoubleClickon Geometry asthenewdefaultactionistoEditthegeometry DefaultactionsareshowninboldtypeafterRMBselects RMB SC 4 aImportthegeometrybytheprocedureshown DoNOTDoubleClickonthe Geometry cell 4 bBrowsetotheDesignModeler11 0SP1geometry soda can filled 110 agdb RMB SC Step4 ImportandModifytheGeometry 4 dSuppressthesolid Soda andthesurfacebody Hole RMB SC 4 eGeneratethechangesinthegeometry Althoughadditionalmodificationscouldbemade butnoneareneeded 4 fSavetheentireProjectviatheDM Save icon Step5 EdittheModelinMechanical 5 aEditthemodelinWorkbenchMechanical SinceEditisthedefaultaction double clickingontheModelcellisalsoacceptablehere RMB SC 5 bSelecttheMKSUnitssystemRecallthatMechanicalisnotnativeinWorkbench sotheUnitsheremaynotmatchtheProjectUnitsNote Althoughtheunitsystemusedfordataentryandpost processingistheMKSsystem theactualunitsystemusedbytheAUTODYNsolveristhemm mg mssystem becauseitprovideshigheraccuracy ThiswillbeshownlaterwhentheAnalysisSettingsarediscussed Step5 EdittheModelinMechanical RigidSteelPunch moveddownwards FlexibleAluminumSodaCan crushed RigidSteelDie fixed 5 cDefinetheAluminumCanproperties StiffnessBehavior FlexibleThickness 0 00025metersMaterialAssignment My Aluminum 5 dDefinethePunchandDieproperties StiffnessBehavior RigidMaterialAssignment StructuralSteel Step5 EdittheModelinMechanical 5 eReviewtheContactspecifications Keepcontactdefinitiondefaults 5 fSavetheProject Note ThereisnoSaveiconinMechanical Step6 SetSizingControlsandMeshModel 6 dOrientthemodeltoselectthe8edgesthatdefinethecancircumferences withtheLeftMouseButton UsetheCtrlkeyformultipleselections asneeded 6 aSelecttheMeshbranch6 bSpecifytheMeshDetails PhysicsPreference ExplicitElementSize 0 010meters6 cChoosetheEdgeselectionfilter RMB anywhere 6 eWiththe8edgesstillhighlighted Insert RMBanywhereongraphicsscreen anEdgeSizing SC SC Step6 SetSizingControlsandMeshModel 6 fSpecifytheEdgeSizingDetails Type NumberofDivisionsNumberofDivisions 36Behavior Hard6 gGeneratetheMesh RMBoneitherMeshbranchorEdgeSizingbranch RMB SC Meshview Step7 DefinetheAnalysisSettings 7 aSpecifytheAnalysisSettings EndTime 6 0e 4secondsAutomaticMassScaling YesMinimumCFLTimeStep 1 0e 7sec SC 7 bSettheSolveUnits mm mg msNote Themm mg msunitsystemisthemostaccurateinmostsimulations soitistheonlyonecurrentlyavailable Althoughmoresolverunitsystemswillbeavailableinthefuture anyunitsysteminthedrop downlistmaybeusedtoenterdataand ordisplaytheresults Step7 DefinetheAnalysisSettings 7 cKeeptheremainingdefaultsNote Therearemultiplewaystocontroltheerosionofanelement Inthiscase theelementwillonlyfailwhenthegeometricstrainreaches150 7 dUsethedefaultnumberofdatasetstosaveduringthesolution Dependingontheanalysis thisnumbermayneedtobeincreased butthatrequiresadditionaldiskspace sobejudicioushere Step8 ApplyBCsandExternalLoads 8 aFixtheSteelDie base SelecttheBodyfilterInsertaFixedSupportunderExplicitDynamicsSelectthesteeldieApplytheselection RMB SC SC Step8 ApplyBCsandExternalLoads 8 bDisplacetheSteelPunchInsertaDisplacementunderExplicitDynamicsSelectthesteeldieApplytheselection RMB SC SC Step8 ApplyBCsandExternalLoads Note Thepunchspeedandabruptchangeindirectionareunrealistic butsufficientfordemonstrationpurposes Normally themovementwouldbeprescribedaccordingtoaSINEwavefunction 8 cSpecifythevertical Y displacementtobeaTabularloadandsetboththeXandZdisplacementstobezero 8 dRamptheYdisplacementasfollows Time 0 0secY 0 0metersTime 5e 4secY 0 060metersTime 6e 4secY 0 030meters Step9 InsertResultItemstoPostprocess 9 aInsertaTotalDeformationplotrequestundertheSolutionbranch 9 bInsertanEquivalent von Mises StressplotrequestundertheSolutionbranch Therigidbodies i e thepunchanddie willnotshowstress RMB RMB SC SC SC SC SC SC Step9 InsertResultItemstoPostprocess 9 cInsertanEquivalentPlasticStrainplotrequestundertheSolutionbranch RMB SC SC SC Note Eventhoughasingletimepoint attheendoftherun isspecified thecompletesetofresultscanbeviewed includinganimations Recallthatthedefaultoutputcontrols 20equallyspacedtimepoints wasretainedundertheAnalysisSettingsbranch 9 dSavetheProjectagain Step10 RuntheAUTODYNSimulation 10 aSelectSolverOutputunderSolutionInformationandSolvethesimulation TheSolverOutputshowstherunstatistics includingtheestimatedclocktimetocompletion Anyerrorsorwarningsarealsonoted Terminationdueto wrapuptimereached isexpectedhere SC Step10 RuntheAUTODYNSimulation 10 bSelectEnergySummaryunderSolutionInformationtoreviewtheglobalstatistics Notetheabruptchangesinkineticenergyduetotheunrealisticloadingscenario TIME 5 0e 4secondsoccursaround3200cyclesintorun Constantvelocityafterstartingfromrest Step11 ReviewtheResults 11 aSelectTotalDeformationandShowtheElementsunderTrueScale Themaximumdeformation 0 060m exceedsthepunchvalueduetothemomentuminvolved i e anexcessivepunchspeedwasusedtoreducetherequiredcomputerruntime SC Step11 ReviewtheResults 11 bAnimatetheresultsbysettingthecontrolsasshownbelowandthenpressingtheAnimationbutton Fortransientdynamics thedefaultDistributedmodeisinadequate asitlinearlyinterpolatesbetweensavedresults TheResultSetsmodeisoptimal asitusestheactualsaveddata Toreviewastaticresult justclickonthedesiredTimeorValuefromtheTabularDataandusetheRMBtopickRetrieveThisResult Thegivenstatewillthenbeshown RMB Pickthese2first Thenpickthis Pickthistosavetheanimation Toretrieveagivenresult Step11 ReviewtheResults 11 cRepeattheprocedure ifdesired forthevon Misesequivalentstressresults Note Nostresscandevelopinarigidbody ThepunchanddieareeachcondensedouttoamassattheirrespectivecentersofgravitywithsixDOFsactive Contactisbasedontheexteriorsurface soasixDOFbodycanhaveacomplicatedcontactsurface SC Step11 ReviewtheResults 11 dRepeattheprocedureonelasttimefortheequivalentplasticstrainresults 11 e HidethePunchandDieforabetterviewoftheresults PertheAnalysisSettings erosiondoesnotoccuruntilthegeometricstrainis1 50 SC SC RMB Step12 ReviewtheOutputFiles 12 aPickFilesundertheViewmenutoaccesstheProjectfiles 12 bSelectOpenContainingFolderviatheRMBoptionfortheAUTODYNprintfile admodel prt RMB Step12 ReviewtheOutputFiles 12 cDoubleclickonthefileadmodel prt 12 dAsnotedearlier thesolverunitssystemwasmm mg msinordertomaximizetheaccuracy AftertheSimulationisdone theresultsareconvertedbackintothecurrentMechanicalunitssystem Step12 ReviewtheOutputFiles 12 eTheAUTODYNprintcontainstheMaterialSummaryinformationandrunstatistics TheEnergyandMomentumareshownonbothamaterialbasisandaPartbasis shownhere Step12 ReviewtheOutputFiles 12 fTheEnergyandMomentumBalance MassScaling andRunTimesarealsoincludedintheadmodel prtfile 12 gNomasswasaddedtothemodel sincethetimestepswereallabovetheMini