ABAQUS子程序USDFLD.

Abaqus/CAEUser'sManual12.8.5Definingfieldvariablesatamaterialpoint（在一个材料点定义场变量）InAbaqus/StandardyoucanintroducedependenceonsolutionvariableswithusersubroutineUSDFLD.Thissubroutineallowsyoutodefinefieldvariablesatamaterialpointasfunctionsoftime,ofanyoftheavailablematerialpointquantitieslistedin“Abaqus/Standardoutputvariableidentifiers,”Section4.2.1oftheAbaqusAnalysisUser'sManual,andofmaterialdirections.Materialpropertiesdefinedasfunctionsofthesefieldvariablesmay,thus,bedependentonthesolution.UsersubroutineUSDFLDiscalledateachpointforwhichthematerialdefinitionincludesareferencetotheusersubroutine.（在ABAQUS里面，你能够用子程序USDFLD来求解变量。USDFLD允许你将一个材料点上的场变量定义为时间函数，能够使用到的材料点在用户使用手册4.2.1节中“abaqus输出变量的标识码”中被提及到。材料的特性被定义作为场变量的函数，因此依赖于求解方法。）（在每个被定义材料性能的点USDFLD能够被调用）ToincludeareferencetousersubroutineUSDFLDinamaterialdefinition:1.FromthemenubarintheEditMaterialdialogbox,selectGeneralUserDefinedField.(ForinformationondisplayingtheEditMaterialdialogbox,see“Creatingoreditingamaterial,”Section12.7.1.)2.ClickOKtoclosetheEditMaterialdialogbox.Alternatively,youcanselectanothermaterialbehaviortodefinefromthemenusintheEditMaterialdialogbox(see“Browsingandmodifyingmaterialbehaviors,”Section12.7.2,formoreinformation).Abaqus/CAEUser'sManual（子程序USDFLD在材料中的定义过程可参考下面：1.在编辑材料的对话框中，选择General-UserDefinedField2.点击OK关闭编辑材料的对话框，或者在编辑对话框中选择另外的一个材料特性。）======================================================================================================================================================================================================================================================================================AbaqusUserSubroutinesReferenceManual1.1.49USDFLDUsersubroutinetoredefinefieldvariablesatamaterialpoint.（在一个材料点上使用USDFLD重新定义场变量）Product:Abaqus/StandardReferences（参考）“ObtainingmaterialpointinformationinanAbaqus/Standardanalysis,”Section2.1.6“Materialdatadefinition,”Section20.1.2oftheAbaqusAnalysisUser'sManual*USERDEFINEDFIELD“Damageandfailureofalaminatedcompositeplate,”Section1.1.14oftheAbaqusExampleProblemsManual“USDFLD,”Section4.1.24oftheAbaqusVerificationManualOverview（概述）UsersubroutineUSDFLD:allowsyoutodefinefieldvariablesatamaterialpointasfunctionsoftimeorofanyoftheavailablematerialpointquantitieslistedintheOutputVariableIdentifierstable(“Abaqus/Standardoutputvariableidentifiers,”Section4.2.1oftheAbaqusAnalysisUser'sManual)excepttheuser-definedoutputvariablesUVARMandUVARMn;canbeusedtointroducesolution-dependentmaterialpropertiessincesuchpropertiescaneasilybedefinedasfunctionsoffieldvariables;willbecalledatallmaterialpointsofelementsforwhichthematerialdefinitionincludesuser-definedfieldvariables;mustcallutilityroutineGETVRMtoaccessmaterialpointdata;canuseandupdatestatevariables;andcanbeusedinconjunctionwithusersubroutineUFIELDtoprescribepredefinedfieldvariables.（子程序USDFLD：1.允许你在一个材料点定义场变量作为时间函数，在输出变量的标示符中列出了所有材料点的变量，除了用户定义的输出变量和uvarmuvarm。2.能够用来介绍材料的性能，并且这种性能能够被定义为场变量的函数。3.在各元素的材料点中，用户定义的场变量能够被调用。4.必须调用使用程序GETVRM来接入材料点数据5.可以和UFIELD一起使用来描述预定义的场变量）Explicitsolutiondependence(明确解的关系)Sincethisroutineprovidesaccesstomaterialpointquantitiesonlyatthestartoftheincrement,thesolutiondependenceintroducedinthiswayisexplicit:thematerialpropertiesforagivenincrementarenotinfluencedbytheresultsobtainedduringtheincrement.Hence,theaccuracyoftheresultsdependsonthesizeofthetimeincrement.Therefore,youcancontrolthetimeincrementinthisroutinebymeansofthevariablePNEWDT.（由于程序提供的接入点只是在增量的开始，解之间的相互关系应该被明确：在增量的过程中，材料的性能不应该被得到的结果所影响。因此，结果的准确性依赖于时间增量的大小。因此，你能通过PENWDT来控制程序中的时间增量。）Definingfieldvariables(定义场变量)BeforeusersubroutineUSDFLDiscalled,thevaluesofthefieldvariablesatthematerialpointarecalculatedbyinterpolationfromthevaluesdefinedatthenodes.Anychangestothefieldvariablesintheusersubroutinearelocaltothematerialpoint:thenodalfieldvariablesretainthevaluesdefinedasinitialconditions,predefinedfieldvariables,orinusersubroutineUFIELD.Thevaluesofthefieldvariablesdefinedinthisroutineareusedtocalculatevaluesofmaterialpropertiesthataredefinedtodependonfieldvariablesandarepassedintootherusersubroutinesthatarecalledatthematerialpoint,suchasthefollowing:（在子程序USDFLD被调用之前，通过节点中定义的数值采用差值法计算出材料点的场变量。子程序中场变量的任意改动都是在材料点上的改动：节点场变量保持着数值被定义为初始状态（预定义场变量），或者使用子程序UFIELD,程序中场变量的值被用来计算材料的性能，材料的特性被定义依赖于场变量，并且在其他子程序中被调用。例如下面的程序:）CREEPHETVALUEXPANUHARDUHYPELUMATUMATHTUTRSOutputoftheuser-definedfieldvariablesatthematerialpointscanbeobtainedwiththeelementintegrationpointoutputvariableFV(see“Abaqus/Standardoutputvariableidentifiers,”Section4.2.1oftheAbaqusAnalysisUser'sManual).Accessingmaterialpointdata(材料存储点数据)Youareprovidedwithaccesstothevaluesofthematerialpointquantitiesatthestartoftheincrement(orinthebasestateinalinearperturbationstep)throughtheutilityroutineGETVRMdescribedin“ObtainingmaterialpointinformationinanAbaqus/Standardanalysis,”Section2.1.6.ThevaluesofthematerialpointquantitiesareobtainedbycallingGETVRMwiththeappropriateoutputvariablekeys.ThevaluesofthematerialpointdataarerecoveredinthearraysARRAY,JARRAY,andFLGRAYforfloatingpoint,integer,andcharacterdata,re