Dytran官方经典培训讲义_chapter10_BC

PAT328,Section3,March2001DYT101,Section10,September2002S10-1SECTION10LAGRANGIANBOUNDARYCONDITIONSPAT328,Section3,March2001DYT101,Section10,September2002S10-2SINGLEPOINTCONSTRAINT-SPCPreventsapointmovinginaparticulardirection.MustbeinitializedintheCaseControlsection:SPC=SIDAnySPCnentriesnotselectedincasecontrolareignored.Thedisplacementcoordinatesystemoftheconstrainedgridpointdeterminesthedirectionthattheconstraintisappliedin.Canbeusedtomodelboundaryconditionsandplanesofsymmetry.Anycomponentingridcoordinatesystemcanbeconstrained.Componentsinagridcoordinatesystemarereferredbydigits1to6.Anycombinationispossible,e.g.23,156.SPC=100BEGINBULK...SPC,100,27,123SPC1,100,156,19,THRU,28PAT328,Section3,March2001DYT101,Section10,September2002S10-3ROTATIONALBOUNDARYCONDTION–SPC2Usedtomodelrotationalboundaryconditionsongridpoints.MustbeselectedinCaseControlSPC=SIDPAT328,Section3,March2001DYT101,Section10,September2002S10-4SINGLEPOINTCONSTRAINTINLOCALCOORDINATES–SPC3Usedtodefineasinglepointconstraintinalocalcoordinatesystemoracascadeoftwolocalcoordinatesystems.MustbeselectedinCaseControl.SPC=SIDPAT328,Section3,March2001DYT101,Section10,September2002S10-5ENFORCEDMOTIONPrescribesthemotionofgridpoints.Forceofpressureloading-TYPE=2inTLOAD1definition.MustbeselectedinCaseControl.Anyloading(TLOADnentry)notselectedinCaseControlisignored.Enforcedmotioncanbeprescribedinalocalcoordinatesystem.PAT328,Section3,March2001DYT101,Section10,September2002S10-6ENFORCEDGRIDPOINTMOTIONSpecifiedpointscanhavetheirvelocityset.Velocity-TYPE=2inTLOAD1definitionTLOAD1,100,110,,2,120DAREAdefinesmagnitudeoftranslationalorangularvelocityperDOF.FORCEdefinesmagnitudeanddirectionoftranslationalvelocity.MOMENTdefinesmagnitudeanddirectionofangularvelocity.Velocitycanvaryarbitrarilywithtime.TheTABLED1entrygivesthevariationofvelocity.TLOAD=100BEGINBULK...TLOAD1,100,110,,2,120TABLED1,120,,,,,,,,++,0.0,0.0,1.0,1.0,ENDTFORCE,110,27,,-6.0,,1.0PAT328,Section3,March2001DYT101,Section10,September2002S10-7ENFORCEDMOTIONFORCEinCORDXXXIfonaFORCEentryaCIDisreferenced,theenforcedmotionisprocessedinalocalcoordinatesystem.FORCE,110,27,2,-6.0,,1.0PAT328,Section3,March2001DYT101,Section10,September2002S10-8RIGIDWALLS-WALLModelsarigidplanewhichspecified”slave”pointscannotpenetrate.Usedtomodelhard,undeformabletarget.Defineapointonthewallandavectorperpendiculartoit,pointingtowardsthemodel.Twokindsofcontact:PENALTYMethod:Allowedpenetration.Forceincreasesasnodespenetratedeeper.Canhavefriction.KINEMATICMethodNodesareputbackontheSurface.ImpulseisappliedtoNodes.Cannothavefriction.WALL,101,0.0,0.0,0.0,0.0,0.0,1.0,102,++,PENALTY,0.2SET1,102,1,THRU,1999PAT328,Section3,March2001DYT101,Section10,September2002S10-9TIEDCONNECTIONSTwomesheswithdifferentcoarsenessarepermanentlytiedtogetherduringtheanalysis.Allowsbeam,shellandsolidmeshestobetiedtogetherwithouttheneedforcoincidinggridpointlocations.Possiblegapsbetweenthemeshescanberequestedtobeclosed.Notrecommendedinareaswherestresspeaksorfailureisexpected.Threetypesoftiedconnections:TwosurfacestiedtogetherGridpointstiedtoasurfaceShelledgetiedtoashellsurfacePAT328,Section3,March2001DYT101,Section10,September2002S10-10TWOSURFACETIEDTOGETHER(RCONN)Twosurfacesarepermanentlytiedtogetherduringtheanalysis.Mastersurface:alwaysattachedtothecoarsemesh.Slavesurface:alwaysattachedtothefinermesh.Lumpingforcesandvelocitiesaccordingtoshapefunctions.Forces:slavepointsmasterpointsVelocities:masterpointsslavepointsExample:Twosolidsaretiedtogetheralongtheircommonsurface7and8.RCONN,1,SURF,SURF,7,8PAT328,Section3,March2001DYT101,Section10,September2002S10-11GRIDPOINTSTIEDTOASURFACE(RCONN)Individualgridpointsaretiedtoasurface.SlavesurfacetypeisGRIDandOPTIONmustbesettoNORMAL.Mastersurfacemustbedefinedasasetofsegments.Onlythetranslationaldegreesoffreedomaretied.Example:Thenode1to10ofabeammesharetiedtotheshellsurface7.RCONN,1,GRID,SURF,3,7,NORMALSET1,3,1,THRU,10PAT328,Section3,March2001DYT101,Section10,September2002S10-12SHELLEDGETIEDTOASHELLSURFACEConnectsbeamsorshell-edgestoshellelements.SlavesurfacetypeisGRIDandOPTIONmustbesettoSHELL.Mastersurfacemustbedefinedasasetofsegments.Translationalandrotationaldegreesoffreedomaretied.Example:Theedgegridpoints1to10ofashellmesharetiedtotheshellsurfacenumber7.RCONN,1,GRID,SURF,3,7,SHELLSET1,3,1,THRU,10PAT328,Section3,March2001DYT101,Section10,September2002S10-13RIGIDBODYELEMENTS(RBE2)Definesasetofgridpointsthatformarigidbody.Thisentryallowsparticulardegreesoffreedomofasetofgridpointstobetiedtogethersothattheyalwaysmovethesameamount.Usedtomodelspotwelds,butelementscannotfail.Example:Nodes1to28willhavethesamedisplacementinxandz-directionasnode55.RBE2,12,55,13,1,THRU,28Insteadofdefiningtiedcomponents,itisalsopossibletousetheFULLRIGoption.Thiscausesthesetofgridpointstobehavelikeasinglerigidbodyelement.ThenameoftheRBE2willbecomeFRnumber.Example:Nodes1to28and55willbehavelikearigidbody.ThenamewillbeFR12.RBE2,12,55,FULLRIG,1,THRU,28PAT328,Section3,March2001DYT1