多维应力状态下裂纹扩展规律研究

Study of Regular Expansion of Fatigue Crack Expansion Under Complicated Stress

通过对具有预裂纹的圆柱形带缺口试件的高温低周疲劳试验，并借助于带有非硬化区的双曲面模型程序，进行了轴对称问题的循环应力、应变计算。研究表明三维应力状态下，裂纹扩展速率ｄａ／ｄＮ可用当量Ｊ积分范围ΔＪｅｑ及当量应变能密度ΔＷｅｑ进行表征。

A high-temperature low cycle fatigue experiment is conducted on a cylindrical specimen with preexisting crack at the notch root, and the cyclic strain and stress of axial symmetry is calculated by means of the program of two surface′s model within on-harden range. The result shows that the crack propagation rate d a /d N can be characterized by equivalent J -inteqral range Δ Jeq and equivalent strain energy density Δ equnder threedimensional stress.