非比例载荷下缺口件疲劳寿命有限元分析  

Finite Element Analysis of Fatigue Life for Notched Specimen under Nonproportional Loading

作　　者：金丹[1] 王巍[1] 田大将[1] 林伟[1] 

机构地区：[1]沈阳化工大学能源与动力工程学院,沈阳110142

出　　处：《机械工程学报》2014年第12期25-29,共5页Journal of Mechanical Engineering

基　　金：国家自然科学基金(11102119);辽宁省教育厅(L2011066);国家重点基础研究发展计划(973计划;2011CB706504)资助项目

摘　　要：针对Mod.9Cr-1Mo铁素体钢V型缺口件进行一系列非比例低周疲劳试验.试验结果表明,除圆路径外,各路径下裂纹萌生寿命占总寿命的60％～77％,与先前文献相比较,其分散性较小.采用ANSYS软件进行模拟计算,材料弹塑性特性采用Von Mises屈服准则、多线性随动硬化律和单轴循环应力应变曲线来描述.使用柱坐标系,通过固定试件一端,另一端加轴向和周向位移来实现拉扭应变控制.有限元模拟结果表明,各路径下缺口根部均产生了明显的应力集中,第一主应变、等效应变的最大值均发生在缺口根部.基于模拟得到的缺口根部的应力应变结果,采用Smith-Watson-Topper（SWT）方法进行疲劳寿命预测,除针对单轴路径预测结果偏低外,大部分预测结果位于2倍分散带内.A series of tests for low cycle fatigue are conducted for the notched specimen of Mod.9Cr-1Mo ferrite steel under multiaxial loading.The test results show that the initiation life is 60％-77％ of the total life for all the strain paths,except circle path.On the whole,the scatter degree is smaller comparing with previous results from the literatures.ANSYS software is used for simulating and the Von Mises yield criterion,multilinear kinematic hardening rule and uniaxial cyclic stress-strain curve are employed to indicate the material elastic-plastic behavior.In the cylindrical coordinate,one end is fixed and another one is subjected to the axial displacement and circumference displacement to gain the strain control as those in the test.For all strain paths,the stress concentration is observed in the notched root and the maximum of the first principal strain and Von Mises strain occur in the notched root.Smith-Watson-Topper（SWT） approach is employed to predict the fatigue life based on the simulation results.On the whole,the most prediction results are in a factor-2 scatter band,except conservative prediction result for uniaxial path.

关 键 词：MOD 9CR-1MO钢 缺口件 非比例载荷 有限元分析 疲劳寿命预测 

分 类 号：TG155[金属学及工艺—热处理]