多级载荷作用下的疲劳寿命可靠性计算方法

DETERMINATION OF FATIGUE RELIABILITY UNDER COMPLEX LOADING

以不同应力水平下的破坏率相等进行损伤等效转换出发，建立了新的非线性累积损伤模型。在此基础上，得出疲劳寿命服从对数正态分布时多级载荷下的疲劳寿命可靠度计算方法。最后讨论了Ｐ─Ｓ─Ｎ曲线是幂函数和指数函数时的计算公式。

A new non-linear accumulate damage model was derived from the concept of equal failure probabilities under different stress levels. Based on this model,a method of calculating fatigue reliability under complex loading was obtained when the fatigue life is obeying logical normal distribution. At last, the calculating formulas were discussed when the P-S-N curve is described as a power function or an exponential function.