microelastic-plastic nonlinearity on fatigue damage accumulation.pdf

《microelastic-plastic nonlinearity on fatigue damage accumulation.pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、1Dependenceofmicroelastic-plasticnonlinearityofmartensiticstainlesssteelonfatiguedamageaccumulationJohnH.CantrellNASALangleyResearchCenterMailStop231Hampton,VA23681USA(ReceivedSelf-organizedsubstructuralarrangementsofdislocationsformedinwavyslipmetalsduringcyclicstress-induce

2、dfatigueproducesubstantialchangesinthematerialmicroelastic-plasticnonlinearity,aquantitativemeasureofwhichisthenonlinearityparameterβextractedfromacousticharmonicgenerationmeasurements.Thecontributionstoβfromthesubstructuralevolutionofdislocationsandcrackgrowthforfatiguedmart

3、ensitic410CbstainlesssteelarecalculatedfromtheCantrellmodel[Proc.Roy.Soc.LondonA460,757(2004)]asafunctionofpercentfullfatiguelifetofracture.AwaveinteractionfactorfWIisintroducedintothemodeltoaccountexperimentallyfortherelativevolumeofmaterialfatiguedamageincludedinthevolumeof

4、materialsweptoutbyaninterrogatingacousticwave.Forcyclicstress-controlledloadingat551MPaandfWI=0.013themodelpredictsamonotonicincreaseinβfromdislocationsubstructuresofalmost100percentfromthevirginstatetoroughly95percentfulllife.Negligiblecontributionsfromcracksarepredictedinth

5、israngeoffatiguelife.However,2overthelastfivepercentoffatiguelifethemodelpredictsarapidmonotonicincreaseofβbyseveralthousandpercentthatisdominatedbycrackgrowth.Thetheoreticalpredictionsareingoodagreementwithexperimentalmeasurementsof410Cbstainlesssteelsamplesfatiguedinuniaxia

6、l,stress-controlledcyclicloadingat551MPafromzerotofulltensileloadwithameasuredfWIof0.013.PACSnumbers:62.20.Mk;61.72.Hh;62.65.+k;43.25.Ba3I.INTRODUCTION1Cantrellhasshownthatself-organizedsubstructuralarrangementsofdislocationsformedinwavyslipmetalsduringcyclicstress-inducedfat

7、igueproducesubstantialchangesinthemicroelastic-plasticnonlinearityofthematerialthatisquantifiedbyamaterialnonlinearityparameterβ.Theβparametercanbedetermineddirectlyfrom2,3acousticharmonicgenerationmeasurements.Foragivenstateoffatigueβishighlydependentonthevolumefractionsofve

8、insandpersistentslipbands(PSBs),PSBinternalstresses,dislocationloopl