三维复合型弹塑性断裂研究

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1、南京航空航天大学硕士学位论文三维复合型弹塑性断裂研究姓名：王芳丽申请学位级别：硕士专业：工程力学指导教师：郭万林20090301三维复合型弹塑性断裂研究AbstractWiththerapiddevelopmentofscienceandtechnologyandmaterialsinsuchapplicationareasasaviation,aerospace,automotive,shipbuilding,civilengineering,andsoon,thelarge-scaleandmicro-s

2、calebecomethetrendoftherealstructure.andthethree-dimensionalmixed-modeplasticFractureisoneoftheformsofdamageinengineeringstructureastheloadingofthestructurehasbecomemoreandmorecomplicatedanddiverse.Basedonthethree-dimensionalI/IImixed-modeplasticfractureexp

3、eriment,wefocusedonthethree-dimensionalmixed-modefractureofStressfieldnearcracktipandthecrackangle.Themaincontentsareasfollowing:1．Itisshownthattheangleofthemaximumtangentialstressisthesamewiththeangleoftheminimumthree-dimensionalout-of-planeconstraintfacto

4、rundervariousmixedloadingconditionsofvariousthicknessesspecimens.ThecrackinitiationangleoffiniteelementcalculationbasedonthemaximumtangentialstresscriterionisveryclosetotheexperimentalmeasurecrackinitiationangleunderthemodeIloadingdominating（βeq>65.45°）exce

5、pt8mmthickness.2．Loading-displacementcurvechangeswiththeloadingangle,therelativisticlengthandthickness.ThethicknesseffectonloadingcurveunderthepureIloadingconditionsisthelargest,anditdecreasesthemodeIIloadingcomponentincreasing.Basedonloading-displacementcu

6、rve,loading-lengthofcrackexpandingisdrawnoutwhichcandeterminecrackinitiationloadingofstaticfractureexperiments.Keywords:Mixed-modecrack,Mixed-modetriaxialstressconstraintTz,Relativisticlengtha/W,Thicknesseffect,CrackopeningdisplacementII南京航空航天大学硕士学位论文图表清单图2

7、.1实验加载装置示意图................................................................................................................6图2.2试样形状及尺寸示意图............................................................................................................6图2.3三维弹塑性有

8、限元分析模型....................................................................................................7图2.4有限元网格.....................................................................................