考虑次裂纹时U71Mn钢的主裂纹扩展行为  

Main Crack Propagation Behavior of U71Mn Steel Considering Secondary Crack

作　　者：文良华 李孝滔 李煦[2] 曹世豪[2] 江晓禹[2] 

机构地区：[1]朔黄铁路原平分公司,原平034100 [2]西南交通大学力学与工程学院,成都610031

出　　处：《机械工程材料》2017年第6期79-83,89,共6页Materials For Mechanical Engineering

基　　金：国家自然科学基金资助项目(11472230);国家自然科学基金重点资助项目(U1134202/E050303);四川省青年科技创新团队项目(2013TD0004)

摘　　要：采用ANSYS有限元软件,结合疲劳与磨损耦合模型,模拟计算了10t轮重的车轮以全滑动方式滚过初始长度100μm、扩展角度30°的钢轨表面裂纹时裂纹的等效应力强度因子Keff,研究了钢轨疲劳与磨损的关系并分析了主、次裂纹扩展方向及出现次裂纹时主裂纹的扩展行为。结果表明:钢轨的破坏形式以疲劳损伤为主;当裂纹出现分叉之后,主裂纹尖端的应力集中会得到比较大的缓解,其等效应力强度因子下降较快;当裂纹扩展到长度大于1mm之后,在主裂纹扩展过程中均伴随着次裂纹的出现,且主裂纹扩展方向基本不变,扩展速率逐渐加快,而次裂纹的扩展速率和扩展方向都基本不变。Using the finite element software ANSYS and combining the fatigue and wear coupling model,the equivalent stress intensity factors of cracks were simulated and calculated when the 10-ton wheel rolled over on the rail surface crack that had an initial length of 100μm and an extension angle of 30°.The relationship between rail fatigue and wear was investigated and the propagation directions of the main and secondary cracks and the propagation behavior of main cracks after the secondary cracks appearing were also analyzed.The results show that the destruction mode of the rail gave priority to fatigue damage.When the branched cracks appeared,the stress concentration at the main crack tip would be relatively largely relieved,resulting in a relatively rapid decrease of the equivalent stress intensity factor.After the crack propagation length reached over 1 mm,the main crack further propagation process was accompanied by the appearance of secondary cracks;the propagation direction of the main crack remained unchanged and the propagation rate increased gradually,while the propagation directions and rates of the secondary cracks remained unchanged.

关 键 词：有限元方法 疲劳损伤 磨损 次裂纹 主裂纹 扩展路径 

分 类 号：U211.5[交通运输工程—道路与铁道工程]