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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。
Through the high-temperature and low-cycle fatigue tests of 16MnR notched cylindrical specimens under axial symmetry and three-dimensional stress conditions, the cyclic stress and strain analysis of axisymmetric problems near the notches were carried out using the NHRDS finite element program. Dangerous point of stress, strain and stress equivalent stress equivalent strain value. Based on the basic principle of equivalence concept, the energy loss of material fatigue process was analyzed, and the fatigue life under different strain rates under axial symmetric three-dimensional stress state was evaluated by equivalent plastic strain energy density. Based on the analysis, Effect of fatigue life. The experimental results show that it is feasible to use the equivalent plastic strain energy density to characterize the high temperature and low cycle fatigue life under the condition of axisymmetric three-dimensional stress, and the effect of strain rate on the fatigue life can be obtained by using the strain constant in the fatigue life evaluation formula Function to represent the method to be quantified.