受压弯作用构件半椭圆表面裂纹的疲劳扩展分析  

Fatigue Propagation Analysis of Semi-elliptical Surface Crack Subject to Compression-bending Loads

作　　者：张佳敏[1] 耿黎明[2] 陶伟明[1] 

机构地区：[1]浙江大学工程力学系,浙江杭州310027 [2]中国舰船研究设计中心,湖北武汉430064

出　　处：《材料科学与工程学报》2014年第3期408-411,共4页Journal of Materials Science and Engineering

摘　　要：本文给出了半椭圆表面裂纹疲劳扩展的一种有限元仿真分析方法,并对潜艇锥柱结合壳焊趾处压弯联合交变载荷作用下的裂纹扩展进行了计算分析。该方法利用有限元分析计算裂纹前沿应力强度因子,采用Paris公式预测裂纹扩展速率及扩展量,对有限元网格随着裂纹的扩展进行自动重构,从而模拟分析裂纹的疲劳扩展过程。考察了两种初始尺寸半椭圆表面裂纹的情况,计算了裂纹尺寸、应力强度因子随裂纹扩展的变化历程。仿真计算结果表明,初始裂纹尺寸对于疲劳扩展的影响主要体现在初、中期的扩展上,对后期的扩展速率、裂纹形态影响不大;当考虑了焊接区应力集中效应后,扩展的速度提高,总的疲劳扩展寿命下降。本文方法和程序可用于其他较复杂构件表面裂纹的扩展分析。A simulation scheme based on finite element method was presented for fatigue crack propagation of semi-elliptical surface cracks,which was applied to the surface crack analysis at the weld toe of submarine cone-cylinder shell subject to compression-bending alternate loads.In the framework of the simulation method,the crack stress intensity factors were calculated by finite element analysis,the crack growth velocity and extension were predicted by Paris law,and the finite element model was automatically updated as the crack growth.Two cases of different initial crack size were analyzed by the present method.The evolution of crack sizes and intensity factors were calculated.The results indicate that initial crack size has relatively strong effects on the cracking velocity and form at early stage.These effects get weakening at the later stage.When the stress concentration at the weld zone is taken into consideration,the fatigue life is shortened as the crack propagating velocity accelerated.The present method and procedure can be applied to surface crack propagation problems of complicated components or structures.

关 键 词：压-弯构件 疲劳扩展 半椭圆表面裂纹 锥柱结合壳 

分 类 号：O346.1[理学—固体力学]