非均匀介质接触问题的新线性分层模型

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1、北京交通大学硕士学位论文非均匀介质接触问题的新线性分层模型姓名：马鑫申请学位级别：硕士专业：工程力学指导教师：汪越胜20080601ABSTRACTFunctionallygradedmaterials(FGMs)possesspropertiesthatvarygraduallywithlocationwithinthematerial．Usedascoatingsandinterfacialzonestheytendtoreducestressconcentrationresultingfrommaterialproperty

2、mismatch，increasethebondingstrength，improvethesurfacepropertiesandprovideprotectionagainstadversethermalandchemicalenvironment．nustheconceptprovidesthematerialsscientistsandengineerswithailimportanttooltodesignnewmaterialsforsomespecialapplications，forexample，inaerosp

3、ace，automobile，biomedicine，nuclearenergy,gasturbineengineandmanyotherfields．RecentresearchesindicatethatFGMusedascoatingscanimprovetheresistancetocontactdeformationanddamagethatcannotberealizedinconventionalhomogeneousmaterials．Therefore，thecontactmechanicsofFGMbecome

4、sasignificantresearchtopic．Inthepresentwork，thenewlinearmulti—layeredmodelisusedtosimulatetheFGMwitharbitrarilyvaryingmaterialproperties．Themodelisbasedonthefactthatanarbitrarycurvecanbeapproachedbyaseriesofcontinuousbutpiecewiselinearcur'ves，inthepresentwork，usingthe

5、reciprocaloftheshearmodulus(flexibilitycoefficient)simulatetheFGM，theFGMisdividedintoseveralsub-·layersandineachsub--layerstheshearmodulusisassumedtobelinearfunctionandiscontinuousatthesub—interfaces．Withthemodel．thefollowingproblemsareinvestigated：(1)Stressanddisplac

6、ementfieldsofafunctionallygradedcoatedhalf-planesubjectedtonormalandtangentialconcentratedlineloadsactingatthecoatingsurfaceareobtained．Fortheproblemunderplanestraindeformation，Young’SmodulusorshearmodulusoftheFGMmayvaryarbitrarilywhilePoisson’Sratioistakentobeaconsta

7、nt．(2)Withtheabovesolutionasthefundamentalsolution，thefrictionlesscontactofrigidpuncheswithvariousshapesonafunctionallygradedcoatedhalf-planearesolved．ByusingthetransfermatrixmethodandFourierintegraltransformtechnique，themixedboundaryvalueproblemsmentionedaboveareredu

8、cedtoaCauchysingularintegralequationorasetofsuchsingularintegralequationsthatcanbenumericallycalculatedtoobtainedmaterialpro