wavelet transform analysis of acoustic emission generated during friction stir welding of 6061 aluminum外语英文电子书

《wavelet transform analysis of acoustic emission generated during friction stir welding of 6061 aluminum外语英文电子书》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、Availableonlineatwww.sciencedirect.comSC!ENC2@DIRECTBMACHrNETOOLS&MANUFACTUREOe5lGN.RESE.&JICHANDAPPUt.lnQNPergamonfoccmationalJournalofMachine'Tools&Manufacrure43(2003)1383-1390VVavelettransformanalysisofacousticemissioninmonitoringfrictionstirweldingof6061aluminumChangmingChen,RadovanKovacevic

2、*,DraganaJandgricResearchCenterforAdvancedManufacturing,DepamnentofMechanicalEngineering,SouthernMethodistUniversiry,1500InrernationalParkway,Suire100,Richardson,TX75081,USAReceived4February2003;receivedinrevisedform28April2003;accepted7May2003AbstractInthispaper,acousticemission(AE)signalsarede

3、tectedandpreliminarilyanalyzedinordertoinvestigatethepossibilityofapplyingtheAEtechniqueforthein-processmonitoringofanentirefriction-stir-welding(FSW)process.ExperirnemaJtestsarecarriedourusingahigh-speedrotatingtooltraversingontwo,butted6061aluminumalloyplateswiththreeequallyspacedgapsmadeoftwo

4、notchesalignedalongthebuttingjointoftheparts.Thewavelettransform(WT)isusedtodecomposetheAEsignalintovariousdiscreteseriesofsequencesoverdifferentfrequencybands.Therearesignificantsuddenchangesinthebandenergya(themomentwhentheprobepenetratesintoandpullsouroftheweldjoint,aswellaswhentheshouldermak

5、escontactwithordetachesfromtheplates.Thebandenergyvariationduringthetraversingofthetoolover.thedefectedregionreflectstheexistence,location,andsizeofthewelddefects.Athree-dimensionalrepresentationofbandenergyvstimeandscalegivesvaluableinfor•mationonthepotentialwelddefectsduringfrictionstirwelding

6、.Coupledwithacontourmapping,therepresentationcanbeeffectivelyutilizedformonitoringthetransientweldingstateandquicklyidentifyinggapdefects.©2003ElsevierLtd.Allrightsrese~ed.Keywords:Acousticemission;Waveletanalysis;Frictionstirwelding;Processmonitoring;Welddefects'.1.'"1.Introductionwhichprovides

7、foramoreflexibleautomationinmanu•facturing[3].Friction-stir-welding(FSW)isasolid-statematerialAEmonitoringisoneofthemostsensitivetechniquesjoiningmethodresultinginalow-levelofdeformationthatisusefulforreal-timedetectionofcra