ABAQUS分析收敛控制.docx

ABAQUS分析收敛控制.docx

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ABAQUS分析收敛控制

AbaqusAnalysisUser'sManual©

7.2.1Convergeneeandtimeintegrationcriteria:

overview

NumerouscontrolparametersareassociatedwiththeconvergeneeandintegrationaccuracyalgorithmsinAbaqus/Standard.Theseparametersare

assigneddefaultvaluesthatarechosentooptimizetheaccuracyandefficiencyofthesolutionforawidespectrumofnonlinearproblems.Youcanchangethesolutioncontrolparameters,asdescribedinthefollowingsections:

«Abriefsynopsisofthemoreimportantsolutioncontrolparameters,togetherwithadescriptionofthecircumstancesinwhichtheycanbeusedeffectively,isprovidedinCommonlyusedcontrol

parameters,”Section7.2.2.Thissectionislikelytobethemost

usefulforthegeneraluserandshouldbereadfirst.

«Abaqus/Standardincorporatesanempiricalalgorithmdesignedto

solvetheequilibriumequationsofnonlinearsystemsaccuratelyand

economically.Thecriteriausedtoestablishconvergeneeof

nonlinearincrementsandtheautomaticadjustmentofincrementsizebasedontheconvergeneeratearedescribedinConvergeneecriteriafornonlinearproblems,”Section7.2.3.

*Abaqus/Standardallowsyoutochoose“timeintegrationaccuracy

parameters”inproblemsthathaveaphysicaltimescale.Thealgorithmsthatusetheseparametersforautomaticallyeontrolling

timeincrementsizesaredescribedinTimeintegrationaccuracyin

transientproblems,”Section7.2.4.

•Abaqus/CFDallowsyoutochoosetheeontrolparametersusedinanAbaqus/CFDtoAbaqus/StandardortoAbaqus/Explicitco-simulationtoalleviateinstabilityandmeshdistortionduringtheanalysis.

Modifyingthedefaultsolutioncontrols

Thedefaultvaluesforthesolutioneontrolparametersneednotbeadjustedformostcases.Youcanresetthem,however,withinastepdefinition.

Valuesgivenforthesolutioncontrolparametersremainineffectfortheremainderoftheanalysisoruntiltheyarereset.

InputFileUsage:

*CONTROLS

The*CONTROL5ptioncanberepeated,ifnecessary,withdifferentparameters.

Abaqus/CAEUsage:

Stepmodule:

Other—GeneralSolutionControlsEdit:

toggleonSpecify

Resettingalldefaultsolutioncontrols

Youcanrestoreallsolutioncontrolparameterstotheirdefaultvalues.

InputFileUsage:

*CONTROLRESET

Abaqus/CAEUsage:

Stepmodule:

Other—GeneralSolutionControlsEdit:

toggleonResetallparameterstotheirsystem-defineddefaults

7.2.2Commonlyusedcontrolparameters

Products:

Abaqus/StandardAbaqus/CFDAbaqus/CAE

References

Convergeneeandtimeintegrationcriteria:

overview,”Section

7.2.1

•

Section14.15.1ofthe

CONTROLS

•Customizinggeneralsolutioncontrols,Abaqus/CAEUser'sManual

Overview

Solutioncontrolparameterscanbeusedtocontrol:

«nonlinearequationsolutionaccuracy;

«timeincrementadjustment;and

«FSIstabilizationandmeshdistortioninanAbaqus/CFDtoAbaqus/StandardortoAbaqus/Explicitco-simulation.

Thesesolutioncontrolparametersneednotbechangedformostanalyses.Indifficultcases,however,thesolutionproceduremaynotconvergewiththedefaultcontrolsormayuseanexcessivenumberofincrementsanditerations.Afterithasbeenestablishedthatsuchproblemsarenotduetomodelingerrors,itmaybeusefultochangecertaincontrolparameters.

Thissectionpresentsabriefsynopsisofthemoreimportantsolutioncontrolparameters,togetherwithadescriptionofthecircumstancesinwhichtheycanbeusedeffectively.

Valuesgivenforthesolutioncontrolparametersremainineffectforthe

remainderoftheanalysisoruntiltheyarereset.Youcanrestoreall

solutioncontrolparameterstotheirdefaultvalues（seeConvergeneeandtimeintegrationcriteria:

overview,”Section7.2.1）.

Terminology

Inthissectiontheword“flux”meansthevariablewhosediscretized

equilibriumisbeingsoughtandforwhichtheequilibriumequationsmaybenonlinear:

force,moment,heatflux,concentrationvolumetricflux,or

poreliquidvolumetricflux.Theword“field”referstothebasic

variablesofthesystem,suchasthecomponentsofthedisplacementinacontinuumstressanalysisortemperatureinaheattransferanalysis.Thesuperscript■referstoonesuchtypeofequation.ThefieldsandcorrespondingfluxesavailableinAbaqus/Standardarelistedin

Convergeneecriteriafornonlinearproblems,”Section7.2.3.

Definingtolerancesforfieldequations

Solutioncontrolparameterscanbeusedtodefinetolerancesforfieldequations.Youcanselectthetypeofequationforwhichthesolutioncontrolparametersarebeingdefined,asshowninTable7.2.2-1.The

defaulttolerancescanberesetiftheanalysisdoesnotrequirehighaccuracyintheconvergeneecriteria.

Table7.2.2—1Sel