功能梯度材料中裂紋的動(dòng)態(tài)反平面斷裂問(wèn)題.pdf

1、北京交通大學(xué)碩士學(xué)位論文功能梯度材料中裂紋的動(dòng)態(tài)反平面斷裂問(wèn)題姓名：高曉霞申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：固體力學(xué)指導(dǎo)教師：汪越勝20060301AbstractFunctionallygmdedmaterial(FGM)～anewtypeofcompositeshasbeenplayingamoreandmoreimportamroleinmallybranchesofindus訂ialneldsFractureanalysisofsuchm

2、aterials，essentialtotheiroptimⅢndesign，thereforehasbeenmeintereStofscjentistsworkillginthefieldsofmaterialsciencea11dmechaJlicsHowever，thepmpeniesofFGMsmayvaryarbitr撕1yalongacenainspatialdirection，Ⅵ，hichmakesthedirectana

3、lysisverydi衄cultinmathematicsBasedonmefactthatacontinuouscurvecanbeapproximatedbyacontinuousbutpiece—wiselinearcurve，anewmulti—layercdmodelhasbeendevelopedInthisnewmodel，Ⅱ1efhnctionaIlygradednlateriallayerisdividedintose

4、veralsub—layerS，andlinearvafiationsoft王lepmpeniesareassmedineachsub—IayerMaterialpropertiesareta【l(entobecontinuousonthesubinterf砬esa11dequaltot11eirrealvaluesBasedonmenewmultilayeredmodeI，thistlesisinvest培atestheimpactr

5、esponseofacrackinagradedinterfkialzoneorina留adedcoatingsubjectedtotheantiplatleshear10adByudlizingtheL印laceandFourier／Hallkelinte掣al廿ansfornls，theassociatedboundaryvalueproblemiscasCimoasingularintegralequationwimagenera

6、lizedCauchykemelintheL印lacetransf0姍eddomainThehistorvofthedvnalllics廿essintensitvfhctOrsforv撕ousmaterialcombinationsa11dgeome塒esareobtainedbymenumericaltecllniqueofLaplaceinversionComparisonof也epresemresultswithpreViousp

7、ublishedonesforsomespecialex鋤plesshowsthatthepresentmodelisVerye蚯ciemGenerallyspeaking，、vecouldhaVefblIowingconclusions：1)ThedifferenceofthematerialpropertiesbetweenthelowerhaIf二spaceandtheupperone(orthesurfaceofthecoa廿n

8、g)innuencesmepeakpositionobviouslv。_2)Thedi行erencebetweenmegmdientindexoftheshearmoduIusa11dthatofthedensi鉀innuencest11eDSIFssignificantly3)Thevariationofthegradientindexhaslmleinnuenceonmemomentof廿lepeakintheDSIFhistory