Prediction of welding distortion and residual stress in a th

国外关于焊接变形和参与应力分析的研究文献

Available online at http://

ComputationalMaterialsScience43(2008)

353–365

http:///locate/commatsci

Predictionofweldingdistortionandresidualstressina

thinplatebutt-weldedjoint

DeanDenga,*,HidekazuMurakawab

a

ResearchCenterofComputationalMechanicsInc.,TogoshiNI-BLDG7-1,Togoshi,Shinagawa-ku,Tokyo142-0041,Japan

b

JoiningandWeldingResearchInstitute,OsakaUniversity,11-1,Mihogaoka,Ibaraki,Osaka567-0047,Japan

Received1October2007;receivedinrevisedform22November2007;accepted4December2007

Availableonline29January2008

Abstract

Inautomotiveindustry,thinplatepartsarecommonlyused.Duringassemblingprocess,weldingtechnologyisusuallyemployedbecauseofhighproductivity.Weldingdistortionoftenoccursinthinplateweldedstructuresduetorelativelylowsti ness.Thedistortioncausesproblemsnotonlyintheassemblingprocessbutalsointhe nalproductquality.Therefore,predictionandreductionofweldingdeformationhavebecomeofcriticalimportance.Inthisstudy,three-dimensional,thermo-elastic–plastic,largedeformation niteele-mentmethod(FEM)isusedtosimulateweldingdistortioninalowcarbonsteelbutt-weldedjointwith1mmthickness.Tocomparewiththelargedeformationtheory,thesmalldeformationtheoryisalsousedtosimulatetheweldingdeformationandweldingresidualsstress.Meanwhile,thecharacteristicsofweldingtemperature eld,plasticstraindistributionandweldingresidualstressinthinweldedplatesarealsoexaminednumerically.Experimentsarealsocarriedouttomeasuretheweldingdistortioninthethinplatebutt-weldedjoint.Bycomparingthesimulationresultswiththemeasurements,itisfoundthattheresultspredictedbythethermo-elastic–plastic,largedeformationFEMmatchtheexperimentalvalueswell.Moreover,usingtheinherentstrainsobtainedbythethermo-elastic–plasticFEM,http://paringtheresultssimulatedbytheelasticFEMwiththosepredictedbythethermo-elastic–plasticFEM,itisveri edthattheinherentstrainmethodcane ectivelypredicttheweldingdeformationinthethinplatebutt-weldedjointwith1mmthickness.Ó2007ElsevierB.V.Allrightsreserved.

PACS:07.05.Tp;47.11.Fg;65.40.De;81.20.Vj

Keywords:Weldingdistortion;Numericalsimulation;Thinplate;Plasticstrain;Finiteelement;Inherentstrain;Nonlinearanalysis

1.Introduction

Distortioninaweldedstructureistheresultofthenon-uniformexpansionandcontractionoftheweldandsur-roundingbasematerial,causedbytheheatingandcoolingcycleduringweldingprocess.Weldingdistortionhasnega-tivee ectsontheaccuracyofassembly,externalappear-ance,andvariousstrengthsoftheweldedstructures.Inmanycases,additionalcostsandscheduledelaysareincurredfromstraighteningweldingdistortion.Onthe

*

Correspondingauthor.Tel.:+81337853033;fax:+81337856066.E-mailaddress:deng@rccm.co.jp(D.Deng).

otherhand,increasingly,thedesignofengineeringcompo-nentsandstructuresreliesontheachievementofsmalltol-erance.Forthesereasons,predictionandcontrolofweldingdeformationhavebecomeofcriticalimportance.Inthepastdecades,alotofexperimentsandnumericalanalyseshavebeenconductedforpredictingweldingdis-tortion,andalotoffundamentalknowledgehasbeenalsoestablished[1–7].However,thereisverylimitedliteraturedescribingthepredictionandmeasurementofweldingdeformationinthethinplateweldedstructuresespeciallyfortheseweldedstructurewhoseplateorwallthicknessislessthan3.0mm.Recently,Liangetal.[8–10]haveestablishedanumberofdatabasesofweldinginherentdeformationsfortypicalthinplateweldedjointusing

0927-0256/$-seefrontmatterÓ2007ElsevierB.V.Allrightsreserved.doi:10.1016/http://matsci.2007.12.006

国外关于焊接变形和参与应力分析的研究文献

354D.Deng,H.Murakawa/ComputationalMaterialsScience43(2008)353–365

experimentalmethodandinverseanalysismethod,andsomemeaningfulachievementshavebeenobtained.

Inautomotiveindustrythethinplatepartsarecom-monlyemployed,andalotofthinplatepartsareassembledbyarcweldingprocessbecauseofhighproductivity.Duetorelativelysmallsti ness,signi cantweldingdistortionoftenoccurs.Tocomprehensivelyunderstandthecharacteristicsofweldingdeformationinthinplateweldedstructure,itisnecessarytodofurtherfundamentalresearchesbymeansofbothexperimentandnumericalsimulation.

Inthisstudy,three-dimensional,thermo-elastic–plastic,largedeformation niteelementmethod(FEM)isemployedtosimulateweldingdistortionandweldingresid-ualstressinalowcarbonsteelbutt-weldedjointwith1mmthickness.Tocomparewiththelargedeformationtheory,thesmalldeformationtheoryisalsousedtosimulatetheweldingdeformationandweldingresidualsstress.Mean-while,thecharacteristicsofweldingtemperature eld,plas-ticstraindistributionandweldingresidualstressinthinweldedplatesarealsoexaminednumerically.Experimentsarealsocarriedouttoverifythenumericalsimulationmethod.Moreover,usingtheinherentstrains(plasticstrains)computedbythethermo-elastic–plasticFEM,anelasticFEM,inwhichthelargedeformationistakenintoaccount,isalsoutilizedtoestimatetheweldingdeforma-tioninthesamebutt-weldedjoint.2.Experimentalprocedure

Inthisstudy,asimpleexperimentiscarriedouttomea-sureweldingdeformationinthethinplatebutt-weldedjoint.Thebutt-weldedjointconsistsoftwothinmildsteelsheets.Thedimensionofeachsheetis100mmÂ100mmÂ1mm.Theweldingmethodisgasmetalarcwelding(GMAW).Theshieldinggaswas80%Ar+20%CO2.TheweldingwireisYGW16[11].ThedetailedweldingconditionsareshowninTable1.

Toimitatetheweldingconditionsusedinautomobileindustry,aninitialgapbetweenthetwoplatesissettobe0.4mmandapartiallyweldingisperformedinthejoint.Thelengthofweldinglineisabout60mm.Thespecimensareweldedwithoutexternalconstraints.Intheexperi-ments,threeidenticalbuttjointsareperformed.Fig.1showsthepictureofacompletedjoint.

Afterwelding,thede ectionatthecenteroftheweldinglineismeasuredusingasimplemethodasshowninFig.2.Intheexperiments,aVerniercaliperisusedtomeasurethevaluesofh0andh1.Inthis gure,wisthedi erencebetweenh0andh1.Themeasuredvalues(w)ofthesethreejointsare2.20mm,1.90mmand2.10mm.Approx …… 此处隐藏：30413字，全部文档内容请下载后查看。喜欢就下载吧 ……