LSDYNA温度分析手册与算例1

LS-DYNAThermalAnalysisUserGuideAugust1999Copyright©1999LIVERMORESOFTWARETECHNOLOGYCORPORATIONAllRightsReservedMailingAddress:LivermoreSoftwareTechnologyCorporation2876WaverleyWayLivermore,California94550-1740SupportAddress:LivermoreSoftwareTechnologyCorporation7374LasPositasRoadLivermore,California94550TEL:[phone]FAX:[phone]EMAIL:[e-mail]©1999byLivermoreSoftwareTechnologyCorporationAllRightsReservedLS-DYNAThermalAnalysisUserGuide3IntroductionLS-DYNAcansolvesteadystateandtransientheattransferproblemson2-dimensionalplaneparts,cylindricalsymmetricparts(axisymmetric),and3-dimensionalparts.HeattransfercanbecoupledwithotherfeaturesinLS-DYNAtoprovidemodelingcapabilitiesforthermal-stressandthermal-fluidcoupling.ThisdocumentpresentsseveralverysimpleexamplesinusingLS-DYNAforheattransfer,coupledthermal-stress,andcoupledfluid-thermalproblems.TheinputfilespresentedbelowusetheKEY-WORDstructureforclarity.ThestructuredLS-DYNAinputfilerequiresthatthermalcontrolparametersbedefinedoncontrolcards27-30,followedbythermalmaterialdefinitioncardsandthermalboundaryconditioncards.LS-DYNAdistinguishesbetweenastructural,thermal,orcoupledstructure-thermalanalysisbytheCONTROL_SOLUTIONkeywordorbyspecifyingthermalorcoupleontheLS-DYNAexecutionline.ThefollowingproblemsdemonstrateusingLS-DYNAforheattransferandcoupledthermal-stress.1.SteadyStateHeatTransfer-steadystateheattransferinaslabusingshellelements2.TransientHeatTransfer-transientheattransferinarodusing8-nodebrickelements3.ThermalStress-unconstrainedexpansionofablockduetoheatingThefollowingproblemsdemonstrateusingLS-DYNAformanufacturingproblemswheremodelingcoupledfluid,thermal,andmechanicaleffectsareimportant.4.Welding–demonstratestheuseofathermal-mechanicalslidesurface5.MetalForming–demonstratesmodelingoftheconversionofplasticworktoheatLS-DYNAThermalAnalysisUserGuide4Problem1:SteadyStateHeatTransferinaSlabUsingShellElementsThisproblemdemonstratesusingLS-DYNAtosolveasteadystate,2-dimensional,heattransferproblemwithtemperatureboundaryconditions.Thefigurebelowdefinesthegeometry,mesh,andboundaryconditions.TheanalyticalsolutionforthetemperaturedistributioninaslabofthicknesslwithprescribedtemperaturesT0atx=0andTlatx=lisTheanswertothisproblemisT=1atx=1.Notethefollowingmodelparametersdefinedintheinputfilethatfollows:1.Theinputisdefinedusingshellelementswithashellformulationof12foraplanegeometry(note:useshellformulation14foranaxisymmetricgeometry).2.Directanditerativesolversareavailabletosolvethesystemofequationsfortheheattransfercalculations.Thesolvertobeusedisspecifiedin(*CONTROL_THERMAL_SOLVER).ThisproblemusesthedirectsolverACTCOL,whichisaGausstypeprofilesolver.Thediagonalscaledpreconditionedconjugategradientsolver,DSCG,usesmuchlessmemoryandisfasteronmostproblemsthanthedirectsolvers.LS-DYNAInputFile:*KEYWORD$$12345678$$=============================CONTROLDEFINITIONS==============================$*TITLEsteadystateconductioninaslab*CONTROL_SOLUTION1*CONTROL_THERMAL_SOLVER001*CONTROL_TERMINATION1.*DATABASE_TPRINT1.y=12--------4--------6boundaryconditions|||T=0.atnodes1,2|||T=2.atnodes5,6|||y=01--------3--------5answerT=1.atnodes3,4x=0x=1x=2lxTTTTl=--00LS-DYNAThermalAnalysisUserGuide5*DATABASE_BINARY_D3PLOT1.$$==============================PARTDEFINITIONS===============================$*PART$PIDSECIDMIDTMIDslab111$$=============================SECTIONPROPERTIES==============================$*SECTION_SHELL$SECIDELFORM1120.0010.0010.0010.0010.$$========================THERMALMATERIALPROPERTIES==========================$*MAT_THERMAL_ISOTROPIC11.1.1.$$=============================NODEDEFINTIONS=================================$*NODE10.0.20.1.31.0.41.1.52.0.62.1.$$============================ELEMENTDEFINITIONS==============================$*ELEMENT_SHELL111342213564$$========================THERMALBOUNDARYCONDITIONS==========================$*BOUNDARY_TEMPERATURE_NODE100.200.502.602.*ENDLS-DYNAThermalAnalysisUserGuide6Problem2:TransientHeatTransferinaRodUsing8-NodeBrickElementsThisproblemdemonstratesusingLS-DYNAtosolveatransient,3-dimensional,heattransferproblemwithtemperatureboundaryconditions.Thefigurebelowdefinestheproblem.Theanalyticalsolutiontothisproblemis:WiththeFouriernumberdefinedas,F=αt/L2,andthethermaldiffusivitydefinedas,α=k/ρc.Parametersforthisproblemare:thermalconductivityk=1W/mCdensityρ=1kg/m3heatcapacityc=1J/kgCtemperatureinitialconditionTIC=0.temperatureboundaryconditionTBC=1.atx=1.Notethefollowingmodelparametersdefinedintheinputfilethatfollows:1.Transientthermalproblemsaresolvedusingimplicittimeintegration.Therefore,thereisnostabilityconditiononthethermaltimestep.Muchlargertimestepscanbeusedforthethermalsolutionasopposedtothemechanicalsolution,whichusesexplicittimeintegration.Timestepsizeissetin(*CONTROL_THERMAL_TIMESTEP).2.Transientthermalproblemsaresolvedusingageneralizedtrapezoidaltimeintegrationalgorithm.TwospecialcasesaretheCrankNicholsonmethod,α=0.5,andthefullyimplicitmethod,α=1.0,whicharedefinedin(*CONTROL_THERMAL_TIMESTEP).Although,theCrankNicholsonm