abaqus子程序Word下载.docx

abaqus子程序Word下载.docx

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UMATHT:

●canbeusedtodefinethethermalconstitutivebehaviorofthematerialaswellasinternalheatgenerationduringheattransferprocesses;

●willbecalledatallmaterialcalculationpointsofelementsforwhichthematerialdefinitionincludesauser-definedthermalmaterialbehavior;

●canbeusedwiththeproceduresdiscussedin 

“Heattransferanalysisprocedures:

overview,” 

Section6.5.1oftheAbaqusAnalysisUser'

sManual;

●canusesolution-dependentstateVariables;

●mustdefinetheinternalenergyperunitmassanditsvariationwithrespecttotemperatureandtospatialgradientsoftemperature;

●mustdefinetheheatfluxvectoranditsvariationwithrespecttotemperatureandtogradientsoftemperature;

●mustupdatethesolution-dependentstateVariablestotheirvaluesattheendoftheincrement;

●canbeusedinconjunctionwithusersubroutine 

USDFLD 

toredefineanyfieldVariablesbeforetheyarepassedin;

and

●isdescribedfurtherin 

“User-definedthermalmaterialbehavior,” 

sManual.

Useofsubroutine 

UMATHT 

withcoupledtemperature-displacementelements

shouldbeusedonlywithreduced-integrationormodifiedcoupledtemperature-displacementelementsifthemechanicalandthermalfieldsarenotcoupledthroughplasticdissipation.Nosuchrestrictionexistswithfullyintegratedcoupledtemperature-displacementelements.

Usersubroutineinterface

SUBROUTINEUMATHT（U,DUDT,DUDG,FLUX,DFDT,DFDG,

1STATEV,TEMP,DTEMP,DTEMDX,time,Dtime,PREDEF,DPRED,

2CMNAME,NTGRD,NSTATV,PROPS,NPROPS,COORDS,PNEWDT,

3NOEL,NPT,LAYER,KSPT,KSTEP,KINC）

C

INCLUDE'

ABA_PARAM.INC'

CHARACTER*80CMNAME

DIMENSIONDUDG（NTGRD）,FLUX（NTGRD）,DFDT（NTGRD）,

1DFDG（NTGRD,NTGRD）,STATEV（NSTATV）,DTEMDX（NTGRD）,

2time

（2）,PREDEF

（1）,DPRED

（1）,PROPS（NPROPS）,COORDS（3）

usercodingtodefineU,DUDT,DUDG,FLUX,DFDT,DFDG,

andpossiblyupdateSTATEV,PNEWDT

RETURN

END

Variablestobedefined

U

Internalthermalenergyperunitmass, 

U,attheendofincrement.Thisvariableispassedinasthevalueatthestartoftheincrementandmustbeupdatedtoitsvalueattheendoftheincrement.

DUDT

Variationofinternalthermalenergyperunitmasswithrespecttotemperature, 

evaluatedattheendoftheincrement.

DUDG（NTGRD）

Variationofinternalthermalenergyperunitmasswithrespecttothespatialgradientsoftemperature, 

attheendoftheincrement.Thesizeofthisarraydependsonthevalueof 

NTGRD 

asdefinedbelow.Thistermistypicallyzeroinclassicalheattransferanalysis.

FLUX（NTGRD）

Heatfluxvector, 

attheendoftheincrement.Thisvariableispassedinwiththevaluesatthebeginningoftheincrementandmustbeupdatedtothevaluesattheendoftheincrement.

DFDT（NTGRD）

Variationoftheheatfluxvectorwithrespecttotemperature, 

DFDG（NTGRD,NTGRD）

Variationoftheheatfluxvectorwithrespecttothespatialgradientsoftemperature, 

asdefinedbelow.

Variablesthatcanbeupdated

STATEV（NSTATV）

Anarraycontainingthesolution-dependentstateVariables.

Inanuncoupledheattransferanalysis 

STATEV 

ispassedinto 

withthevaluesoftheseVariablesatthebeginningoftheincrement.However,anychangesin 

madeinusersubroutine 

willbeincludedinthevaluespassedinto 

UMATHT,since 

iscalledbefore 

UMATHT.Inaddition,if 

isbeingusedinafullycoupledtemperature-displacementanalysisandusersubroutine 

CREEP,usersubroutine 

UEXPAN,usersubroutine 

UMAT,orusersubroutine 

UTRS 

isusedtodefinethemechanicalbehaviorofthematerial,thoseroutinesarecalledbeforethisroutine;

therefore,anyupdatingof 

donein 

CREEP, 

UEXPAN, 

UMAT,or 

UMATHT.

Inallcases 

shouldbepassedbackfrom 

asthevaluesofthestateVariablesattheendofthecurrentincrement.

PNEWDT

ratioofsuggestednewtimeincrementtothetimeincrementbeingused（DTIME,seebelow）.ThisvariableallowsyoutoprovideinputtotheautomatictimeincrementationalgorithmsinAbaqus/Standard（ifautomatictimeincrementationischosen）.

PNEWDT 

issettoalargevaluebeforeeachcallto 

If 

isredefinedtobelessthan1.0,Abaqus/Standardmustabandonthetimeincrementandattemptitagainwithasmallertimeincrement.ThesuggestednewtimeincrementprovidedtotheautomatictimeintegrationalgorithmsisPNEWDT 

×

DTIME,wherethe 

usedistheminimumvalueforallcallstousersubroutinesthatallowredefinitionof 

forthisiteration.

isgivenavaluethatisgreaterthan1.0forallcallstousersubroutinesforthisiterationandtheincrementconvergesinthisiteration,Abaqus/Standardmayincreasethetimeincrement.Thesuggestednewtimeincrementprovidedtotheautomatictimeintegrationalgorithmsis 

usedistheminimumvalueforallcallstousersubroutinesforthisiteration.

Ifautomatictimeincrementationisnotselectedintheanalysisprocedure,valuesof 

thataregreaterthan1.0willbeignoredandvaluesof 

thatarelessthan1.0willcausethejobtoterminate.

Variablespassedinforinformation

TEMP

Temperatureatthestartoftheincrement.

DTEMP

Incrementoftemperature.

DTEMDX（NTGRD）

Currentvaluesofthespatialgradientsoftemperature, 

TIME

（1）

Valueofsteptimeatthebeginningofthecurrentincrement.

time

（2）

Valueoftotaltimeatthebeginningofthecurrentincrement.

DTIME

Timeincrement.

PREDEF

arrayofinterpolatedvaluesofpredefinedfieldVariablesatthispointatthestartoftheincrement,basedonthevaluesreadinatthenodes.

DPRED

arrayofincrementsofpredefinedfieldVariables.

CMNAME

User-definedmaterialname,leftjustified.

NTGRD

numberofspatialgradientsoftemperature.

NSTATV

numberofsolution-dependentstatevariablesassociatedwiththismaterialtype（definedasdescribedin 

“Allocatingspace”in“Usersubroutines:

Section15.1.1oftheAbaqusAnalysisUser'

sManual）.

PROPS（NPROPS）

User-specifiedarrayofmaterialconstantsassociatedwiththisusermaterial.

NPROPS

User-definednumberofmaterialconstantsassociatedwiththisusermaterial.

COORDS

Anarraycontainingthecoordinatesofthispoint.Thesearethecurrentcoordinatesinafullycoupledtemperature-displacementanalysisifgeometricnonlinearityisaccountedforduringthestep（see 

“Procedures:

Section6.1.1oftheAbaqusAnalysisUser'

sManual）;

otherwise,thearraycontainstheoriginalcoordinatesofthepoint.

NOEL:

Elementnumber.

NPT:

Integrationpointnumber.

LAYER:

Layernumber（forcompositeshellsandlayeredsolids）.

KSPT:

Sectionpointnumberwithinthecurrentlayer.

KSTEP:

Stepnumber.

KINC:

Incrementnumber.

Example:

Usingmorethanoneuser-definedthermalmaterialmodel

Tousemorethanoneuser-definedthermalmaterialmodel,thevariable 

CMNAME 

canbetestedfordifferentmaterialnamesinsideusersubroutine 

UMATHT,asillustratedbelow:

IF（CMNAME（1:

4）.EQ.'

MAT1'

）THEN

CALLUMATHT_MAT1（argument_list）

ELSEIF（CMNAME（1:

MAT2'

CALLUMATHT_MAT2（argument_list）

ENDIF

UMATHT_MAT1 

and 

UMATHT_MAT2 

aretheactualusermaterialsubroutinescontainingtheconstitutivematerialmodelsforeachmaterial 

MAT1 

MAT2,respectively.Subroutine 

merelyactsasadirectoryhere.Theargumentlistcanbethesameasthatusedinsubroutine 

Uncoupledheattransfer

Asasimpleexampleofthecodingofusersubroutine 

UMATHT,consideruncoupledheattransferanalysisinamaterial.Theequationsforthiscasearedevelopedhere,andthecorresponding 

isgiven.Thisproblemcanalsobesolvedbyspecifyingthermalconductivity,specificheat,density,andinternalheatgenerationdirectly.

First,theequationsforanuncoupledheattransferanalysisareoutlined.

Thebasicenergybalanceis

where 

V 

isthevolumeofsolidmaterialwithsurfacearea 

S, 

isthedensityofthematerial, 

isthematerialtimerateoftheinternalthermalenergy, 

q 

istheheatfluxperunitareaofthebodyflowingintothebody,and 

r 

istheheatsuppliedexternallyintothebodyperunitvolume.

Aheatfluxvector 

isdefinedsuchthat

istheunitoutwardnormaltothesurface 

S.Introducingtheaboverelationintotheenergybalanceequationandusingthedivergencetheorem,thefollowingrelationisobtained:

Thecorrespondingweakformisgivenby

where

isthetemperaturegradientand 

isanarbitraryvariationalfieldsatisfyingtheessentialboundaryconditions.

Introducingthebackwarddifferenceintegrationalgorithm:

theweakformoftheenergybalanceequationbecomes

ThisnonlinearsystemissolvedusingNewton'

smethod.

Intheaboveequationsthethermalconstitutivebehaviorofthematerialisgivenby

And