用層狀材料邊界元法研究功能梯度材料中的斷裂力學問題.pdf

1、山東科技大學碩士學位論文用層狀材料邊界元法研究功能梯度材料中的斷裂力學問題姓名：陳英儒申請學位級別：碩士專業(yè)：安全技術及工程指導教師：肖洪天20040501山東科技大學碩士學位論文摘要AbstractItisimportanttOtreatthefracturedamagewhenfunctionallygradedmaterials(FGMs)aredesignedSincethemicro—crackswillappeardurin

2、gthemoldingofmaterialandtheusageofthefunctionallygradedmaterialsthenthesemicrocrackswillgrowandincorporateintomaincracksTheresultwillaffecttheservicelifeandincursafetyhazardSotheproblemsoffracturemechanicsinfunctionallyg

3、radedmaterialshavebeenbecomethevitalresearchdirectionandhottopicsThispaperexaminesthestressintensityfactorsandgrowthofapennyshapedcrackperpendiculartogradedInterfacialZoneofbondedbimaterialsbyusingboundaryelementmethodba

4、sedonthegeneralKelvinsolution(GKSBEM)，thefollowingachievementshavebeengained：ThenumericalvaluevalidationtoGKS—BEMhasb西nmadeThemodifiedmultiregionmethodandtractionsingularelementarerespectivelyusedtotreattheCOplanarcrackp

5、roblemandthesingularityeliminationofthestressofcrackfrontAndthelayerdiscretizationtechniqueisutilizedtoapproximatethedepthmaterialnonhomogeneityofFGMinterfzezoneTheresultshowsthattheGKSBEMCallbeeffectivelyusedtesearchthe

6、fracturemechanicsprobleminFGMsThestressintensityfactorsofthepenny—shapedcrackareresearchedindetailThegradedinterfacialzoneistreatedasanonhomogeneousinterlayerwithitselasticmodulusvaryinginthicknessdirectionThecracksurfac

7、esaresubjecttoeitheruniformnormaltractionoruniformsheartractionTheDon—zerostressintensity／actorsareexam／nedbytakingintoaccounttheeffectsofthenonhomogeneityparameterofthegradedinterfacialzone，thecrackdistancetothegradedin

8、terfacialzone，andthethicknessofthegradedinterfacialzoneForthenormaltractions，thenonzerostressintensityfactorvaluesofthemodeIfracturearepresentedForthesheartraction，thenonzerostressintensityfactorvaluesofthemodesIIandIllf