ansys非线性屈曲分析例子命令流

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1、Non-LinearBucklingAnlyisBucklingAnalysisBucklingisthefailureofcolumnsandrodswhenunderacompressiveload.Therod/column/beambendsbeforetheloadreachesthematerial’syieldpoint.Bucklingoccursduetothestructure’simperfections.StructuresthatcanbuckleBeamsRodsColumnsCrankshaftsPistonandCylinder

2、sSyntheticbonesandprosthetics.AnymechanismthatundergoescompressionBucklingAnalysisFiniteElementMethodFiniteElementAnalysisallowstheSolutionofbucklingproblems.TheColumnisdividedintodifferentnodesandasmallpreloadisadded.ANSYSoffers2bucklingmodes,Eigenvalue(Linear)andanon-linearsolutio

3、nmethod.EigenvalueSolutionForthissolutionmethod,ANSYSusesthelinearEigenvaluemethodtosolveforthebucklingload.TheFollowingisacommandpromptusedtoruntheEigenvaluemethodonANSYS.ANSYSCommandPropmtResultsFromANSYSNon-LinearBucklingAnalysisANSYScanalsoproducenon-linearresults.Thisisdonebyus

4、ingsub-steppedloads,tocalculatethestrainsandgettinganewYoung’sModuluswiththegivenstrain.Aninitialdeformationisplacedinthemodel,sothatANSYSmaybendthemodelandsimulatebuckling(otherwisetheloadwouldshowonlycompressiveresults).ThenextisacommandprompttoinputinANSYStoproducetheanalysis.ANS

5、YSCommandInputGraphedResultsDeformedPlotBehindThescenes:ANSYSItisimportanttounderstandwhattheNLGEOMcommanddoes,andhowitdoesit.ThiscommandallowsANSYStoengageinanon-linearelasticmodelingofthebeam.EquationsThefirstEquationisthePlasticstrainequation:Wherethesuperscript“pl”representsthep

6、lasticstrain,and“el”representsthelinearstrain,andԐnistheoriginalstrain.Tocalculatethelinearstrainthefollowingequationisused:EquationsInthepreviousequationRepresentstheequivalenttotalstrainmeasureandiscalculatedusingthefollowingequation:EquationDescriptionAscanbeseenintheequation,ast

7、henumberofiterationsareincreased,themagnitudeoftheplasticdeformationdecreases(inanewiteration,theresultsfortheplasticstrainisusedastheinitialstrain).Therateofthedecreasealsodecreaseswithanincreasingnumberofiterations,untiltheanswerforthestrainconverges.Thishoweverdoesnottakeintoacco

8、untNon-linearYoungm