利用Hypermesh和nastran创建mnf流程Word文件下载.docx

利用Hypermesh和nastran创建mnf流程Word文件下载.docx

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（3）case_unsupported_cards

ADAMSMNFFLEXBODY=YES,OUTGSTRN=YES,OUTGSTRS=NO

RESVEC=NO

GPSTRAIN（PLOT）=ALL

OUTPUT（POST）

SURFACE101SET100NORMALX3FIBRE=Z1

（4）bulk_unsupported_cards

DTI,UNITS,1,KG,N,M,S

（5）global_case_control

Output栏中

点选EIGRL卡

Gpstress=all

相关文档;

TranslatingMSC.NastranData

TherearetwodifferentinterfacesthatyouusetotranslateMSC.NastrandataforuseinADAMS/Flex.Learnabout:

∙UsingMSC.Nastran2004andAbove

∙VerifyingtheModel

∙ComputingStress/StrainModes

∙XRBSupportforStress/StrainModes

∙ShortenedStress/StrainModes

UsingMSC.Nastran2004andAbove

Startinginversion2004,MSC.Nastranprovidesanimprovedinterfaceforgeneratingmodalneutralfiles（MNFs）.ThenewMSC.NastranADAMSInterfaceallowsyoutogenerateanMNFdirectlyfromMSC.NastranwithoutgeneratinganOUTPUT2file.TheMSC.NastranADAMSInterfacedoesnotrequireaDMAPalteroratranslatortoconvertMSC.NastranoutputfilestoMNFs.

TheMSC.NastranADAMSInterfaceisalicensedfeatureofMSC.Nastran.Formoreinformation,contactyourlocalsalesrepresentative.IfyoualreadyhavetheMSC.NastranADAMSInterfacelicense,refertotheMSC.NastranQuickReferenceGuideandReferenceManualforinformationonhowtouseit.

VerifyingtheModel

TheMSC.Nastrantranslatorwritesasummaryofthemodalneutralfile（MNF）exporttotheterminalwindow.IfyouareusingMSC.Nastran2004orabove,theADAMSinterfacewritesasummaryoftheMNFexporttotheMSC.Nastranoutputfile.Pleasereviewthisdataforanyconcerns.Inparticular,ensurethatthe:

∙Mass,centerofmasslocation,andmomentsofinertiaareasexpected.

∙DuringtheMNFwrite,theconstraintmodesandtheconstrainednormalmodesareorthogonalized.Thisyieldsmodesthatare:

oAnapproximationofthefree-bodynormalmodes.

oInterfacemodes,wheretheinterfaceisthecollectionofalltheattachmentpointDOFs.

Also,verifythatthefreebodynormalmodeshaveareasonablenaturalfrequency.Youshouldexpecttoseesixrigid-bodymodes,unlessdisplacementboundaryconditionsarepresent.

ComputingMSC.NastranStress/StrainModes

ForADAMS/Durabilitytoprocessstressesorstrainsonflexiblebodies,modalstressorstrainshapesneedtobepresentinthemodalneutralfile（MNF）oftheflexiblebody.YoudothisbyhavingMSC.NastranrecoverastressorstrainmodeforeverymodeshapecomputedforComponentModeSynthesis（CMS）.

∙MSC.NastranGridPointStresses

∙Example

∙KnownLimitations,Problems,andRestrictions

MSC.NastranGridPointStresses

BecausemodalinformationcontainedintheMNFcanonlybeassociatedwithnodes,theMSC.Nastrangrid-pointstressdatarecoveryoptionisrequired.ThefollowingCaseControlcommandsarerequiredintheMSC.NastraninputfiletocomputestressorstrainmodesfortheMNF:

∙GPSTRESS:

Requestsgridpointstressesoutput.

∙GPSTRAIN:

Requestsgridpointstrainsoutput.

∙STRESS（PLOT）:

Requestselementstressoutput.

∙STRAIN（FIBER,PLOT）:

Requestselementstrainoutput.

∙OUTPUT（POST）:

Delimiter.

∙SET:

Definesasetofelementsforasurfaceorvolume.

∙SURFACE:

DefinesasurfaceofplateelementsreferencedbytheSETcommand.

∙VOLUME:

DefinesavolumeofsolidelementsreferencedbytheSETcommand.

Formoreinformationonthesecommands,seetheCaseControlsectionoftheMSC.visualNastranQuickReferenceGuide.Formoreinformationoncomputinggridpointstresses,seetheMSC.NastranLinearStaticAnalysisUser'

sGuide.

Notes:

YoucanonlytransferonesurfacestressorstrainfiberofplateelementstotheMNFforprocessinginMSC.ADAMS.IfmorethanonefiberisspecifiedontheSURFACEcard,themsc2mnftranslatorissuesawarningmessageandonlytransfersthefirstsurfacestressfiberitfindsintheOUTPUT2file.

IncludingstressorstrainmodesintheMNFcansignificantlyincreasethefilesize.Therefore,itbecomesevenmoreimportanttooptimizetheMNFifpossible.ForinformationonoptimizingtheMNF,seeOptimizinganMNF.IncludingbothstressandstrainmodeswillfurtherincreasethesizeoftheMNFandisgenerallynotrecommendedforlargemodels,unlessbothquantitiesareneeded.

WhendefiningsubcasesinCaseControl,youmusthavetheGPSTRESS,GPSTRAIN,STRESS,andSTRAINcardsbeforethefirstSUBCASEcard.Inaddition,theOUTPUT,SURFACE,andVOLUMEcardsshouldfollowallsubcasedefinitionsandappearattheendoftheCaseControl.

Example

ThisexampleshowsthechangesthatarerequiredintheMSC.Nastraninputfilewhenthecomputationandtransferofbothstressandstrainmodesaredesired.Becausethemodelcontainssolidandshellelements,asurfaceandavolumearedefinedforcomputingthesegrid-pointstressesandstrains.ThesurfacefiberselectedisZ1andthegrid-pointstress/straincoordinatesystemisconsistentlydefinedtobethebasicFEmodelsystem.

KnownLimitations,Problems,andRestrictions

∙OnlyoneFIBERisoutputonSURFACE.

∙SURFACEorVOLUMEshouldbedefinedinconsistentcoordinate（basic）system.

ExampleofNastranforStressandStrain

MSC.NastranXDBSupportforStress/StrainModes

Youcanstoretheortho-normalstressand/orstrainmodesinXDBfileformatthatarecompatiblewiththemodeshapesinthemodalneutralfile（MNF）andsubsequentmodalresponsesfromanMSC.ADAMSsimulation.Thebenefitsofthiscapabilityare:

∙Unlimitedmodelsize-MSC.PatrancanaccessresultsfromanXDBfileofanysizeandwithmuchmoreefficiencythanfromanOP2file.

∙MSC.Fatigueanalysis-ModalcoordinatesfromMSC.ADAMScanbecombinedwithstressorstrainmodesinXDBfileforveryefficientMSC.Fatigueanalysisusingmodalsuperposition.

∙Element-basedsupport-TheXDBfileformatsupportselement-basedand/orgrid-pointbasedstressorstrain.Element-basedresultsallowyoutoperformadvancedfatigueanalysessuchasmulti-axialfatigueandweldments.

Learnmore:

∙CreatinganXDBFile

∙Limitations

∙Examples

CreatinganXDBFile

TocreateanXDBfilewithstressorstrainmodes,addthefollowingentryintheBulkDatasection:

PARAM,POST,0

ThisisinadditiontothenecessarycommandsthatareaddedtoCaseControl（seeComputingMSC.NastranStress/StrainModes）.Inthecaseofgridpointstressesorstrain,however,oneadditionalcommandisrequiredtooutputgridpointstressorstrainmodes:

STRFIELD=ALL

Notethatifyouareonlyinterestedinworkingwithelement-basedstressorstrain,thiscommandisnotneeded.Formoreinformationontheseentriesandcommandsseethe,MSC.NastranQuickReferenceGuide.

Backtotop

Limitations

∙Grid-pointstrainmodescannotbestoredintheXDBnorcanMSC.Patranpost-processthem.

∙Element-basedstressorstrainmodescannotbestoredintheMNFnorcanADAMS/Durabilitypostprocessthem.

Examples

ThefollowingareexamplesofMSC.Nastraninputdecks.SeetheCaseControlsectionoftheMSC.NastranQuickReferenceGuideformoreinformationontheADAMSMNFcommandthatisbeingusedintheseexamples.

ExampleofRequestingNoGridPointStress/Strain

Inthefollowingexample,nogridpointstressorstrainmodeshavebeenrequested.Onlyelement-basedstrainmodeshavebeenrequestedwithSTRAIN（PLOT）=ALL.ThesestrainswillbestoredintheXDB（PARAM,POST,0）forpostprocessinginMSC.PatranorforcombiningwithMSC.ADAMSmodalresponsesfromADAMS/DurabilityforanMSC.Fatigueanalysis.Thisisthemostefficientprocessforobtainingstrainsforthesolepurposeofperformingafatigueanalysis.IfyouarenotinterestedinviewingstrainsinMSC.ADAMS,thereisnoneedtocomputegrid-pointstrainmodesnorstoringthemintheMNF.Youwillalsoseeasavingsinfilesizeandprocessingtimefromthis.Thesameistrueforstressmodesiftheyaredesiredoverstrains.

SOL103

CEND

ADAMSMNF,FLEXBODY=YES,OUTGSTRS=NO,OUTGSTRN=NO

...

STRAIN（PLOT）=ALL

BEGINBULK

ENDDATA

ExampleofRequestingGrid-PointStressonAllSolidElements

Inthefollowingexample,grid-pointstress（GPSTRESS）modeshavebeenrequestedonallsolidelements（VOLUME）.Thisdata,aswellastheelement-basedstress（STRESS）modes,willbestoredintheXDBduetotheSTRFIELD=ALLcommandandthePARAM,POST,0card.ThegridpointstressmodeswillalsobestoredintheMNFwiththeOUTGSTRS=YESoptionsetontheADAMSMNFcommand.ThisallowsADAMS/DurabilitytopostprocessstressesontheflexiblebodyinMSC.ADAMSusingthemodalstressrecoverytechnique.

ADAMSMNF,FLEXBODY=YES,OUTGSTRS=YES,OUTGSTRN=NO

STRESS（PLOT）=ALL

GPSTRESS=ALL

SET92=ALL

VOLUME12SET92DIRECT

ExampleofRequestingGrid-PointStress

Inthefollowingexample,again,grid-pointstressmodeshavebeenrequested.TheywillnotbestoredintheXDB,however,becausetheSTRFIELD=ALLcommandismissing.Therefore,onlyelement-basedstressmodeswillbeavailableintheXDB.Grid-pointstressmodeswillbestoredintheMNFbecausetheADAMSMNFoption,OUTGSTRSisstillsettoYES.

ShortenedStress/StrainModes

Shortenedstress/strainmodesreferstothecapabilityofdefiningagrouporsubsetofelementsinFEAforstress/strainrecoveryduringmodalneutralfile（MNF）generation.FEAprograms