基于有限元分析的裂纹比拟法估算微动疲劳寿命  

FEM ANALYSIS BASED CRACK ANALOGUE METHOD FOR LIFE PREDICTION OF FRETTING FATIGUE

作　　者：王振亚[1] 刘道新[1] 张晓化[1] 

机构地区：[1]西北工业大学航空学院,西安710072

出　　处：《机械强度》2011年第5期729-734,共6页Journal of Mechanical Strength

基　　金：国家自然科学基金(50671085;50771070);国家863高技术研究发展计划(2007AA03Z521)资助~~

摘　　要：采用Ansys有限元软件对方足微动桥/平面试样接触状态进行分析,确定试样微动接触面上应力场分布和接触面三区(黏着区、滑移区、张开区)分布特征,分析接触面上接触状态随外加交变载荷的变化规律,在此基础上改进微动疲劳(fretting fatigue,FF)寿命估算的裂纹比拟法(crack analogue method,CAM)。选取不同水平的循环载荷及不同名义接触压力对Ti811钛合金试样在350℃下进行微动疲劳试验,验证改进裂纹比拟法(modified crack analogue method,MCAM)的准确性。结果表明,微动疲劳中接触面压应力与剪应力在黏/滑交界区存在突变,张应力幅在滑移/张开分界处达到最大值,裂纹易在此萌生并扩展。改进的裂纹比拟法估算值与实验结果取得良好的一致性。Ansys was applied to analysis the contact status of a plane specimen contacting with a rectangular fretting pad.The distribution of the stresses and the three zones（sticking,slipping and opening） on the contact surface were determined.Evolution of contacting status was also analyzed under fretting cycles.A modified crack analogue method（MCAM） was put forward to predict life of fretting fatigue based on above results.Experiments under different cyclic loads and nominal contact stress were conducted to verify the validity of MCAM.The results show that the normal stress and shear stress change sharply at the edge of the mixed sticking /slipping zones in fretting process.Tensile stress amplitude reaches maximum value at the edge of the mixed slipping /opening zones,where the cracks initiate and propagate more easily.The fretting fatigue life predicted by the MCAM agrees with well experiment results.

关 键 词：微动疲劳 有限元法 裂纹比拟法 寿命预测 钛合金 

分 类 号：O343.3[理学—固体力学] O346.2[理学—力学]