16MnR轴对称三维应力状态下高温低周疲劳寿命评价

通过对 1 6MnR带缺口的圆柱试样的轴对称三维应力状态下高温低周疲劳试验 ,并应用NHRDS有限元程序进行了缺口附近轴对称问题的循环应力、应变分析计算 ,得出了各试样危险点的应力、应变分量值和当量应力、当量应变值。基于当量概念这一基本准则 ,分析材料疲劳过程的能量损耗 ,利用当量塑性应变能密度评价了该材料轴对称三维应力状态下不同应变速率下的疲劳寿命 ,并在此基础上分析了应变速率对疲劳寿命的影响。试验结果表明 ,该材料轴对称三维应力状态下高温低周疲劳寿命用当量塑性应变能密度来表征是可行的 ,应变速率对疲劳寿命的影响可以通过将疲劳寿命评价公式中的材料常数用应变速率的函数来表示的方法得以定量的体现。

Research on Short Cycle Fatigue Life of 16MnR at Elevated Temperature Under Axisymmetrical Three-Dimensional Stress State

Through short cycle fatigue experiments at high temperature on 16MnR specimens with gap at different stain rate, using NHRDS finite element program to analyze and calculate the stress and strain at the gap, analyzing the energy dissipation during the proccess of fatigue, based on the equivalent theory, the short cycle fatigue life of steel at different strain rate was evaluated in this paper. The results show that the short cycle fatigue life of the steel at elevated temperature under axisymmetrical three-dimensional stress state can be characterized by equivalent plastic strain energy density and the influence of strain rate on the short cycle fatigue life can be expressed in quantity through substituting the constants in the evaluating formulas with the functions of strain rate.