基于内聚力单元热障涂层体系失效过程有限元模拟分析-(5662)

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1、loadsinsubstrate.Astensileloadsincrease,thecompressivestressincoatinggraduallytransformedintothetensilestateandverticalcracksfirstlyappearedinthecoating.Whenstraininthecoatingapproachestoabout0.27%,thecoatingbeginstofracture，whichisconsistentwellwiththeexperimentalresults.Th

2、irdly,withthesimilarmethod,theparametersofcohesiveelementmodelabouttheinterfacefractureofTBC/bondcoatwereevaluatedbysimulatingarepresentativesegmentedcoatingunitundertensions.Thewholefractureprocessincludingverticalcracks,interfacedelaminationandspallationofthecoatingwerepre

3、dictedwiththesedeterminedmaterialproperties.Thesimulationresultsshowthatwhenthesubstratestrainis0.43%,acrackattheTBC/bondcoatinterfaceoccursandpropagates.Astheexternaltensileloadsincreasemorelarge,moreandmorecracksquicklynucleateandextendalongtheinterfacedirection.Finally,di

4、fferentcracksconnectwitheachotherattheinterfaceregionandalargedelaminationforms.Theresultsareinagreementwithwiththecorrespondingexperimentalresultsbydigitalimagecorrelationtechnique.Keywords:Thermalbarriercoatings；Cohesivezonemodel；Extendedfiniteelementmethod;Fracture;Mechan

5、icalpropertiesIII目录第1章绪论.........................................................11.1引言........................................................11.2热障涂层材料的研究和发展现状................................21.2.1热障涂层系统..........................................21.2.2热障涂层材料的制备方法...........

6、.....................31.2.3热障涂层的失效机理....................................41.3热障涂层材料的失效检测及其检测方法的发展现状................51.3.1热障涂层材料的失效检测................................51.3.2有限元法的发展及应用现状..............................51.4本文选题的依据和研究内容....................................6第2章基于扩展有限元8

7、wt%Y2O3-ZrO2纯陶瓷弯曲载荷作用下的数值模拟..82.1室验样品的制备..............................................92.2实验测试方案...............................................102.2.1单边切口梁法断裂强度计算公式的改进...................102.3扩展有限元模型.............................................122.4实验结果和分析....................

8、.........................132.4.1单边切口梁法评估断裂强度和断裂韧性...................132.4.2