非正态变量可靠性灵敏度分析方法

RELIABILITY SENSITIVITY METHOD FOR NON-NORMAL VARIABLE

基于极限状态函数矩估计的失效概率计算,提出一种非正态变量可靠性灵敏度分析的新方法。推导极限状态函数的矩对非正态基本变量分布参数的偏导数,并利用失效概率与极限状态函数矩的关系,推导失效概率对非正态基本变量分布参数的偏导数,从而得到非正态变量可靠性灵敏度。用文中方法和改进的一次二阶矩法同时分析对数正态变量的可靠性灵敏度,验证文中方法的正确性;最后运用其方法计算失效概率对指数和Weibull分布参数的灵敏度。

Based on the moment estimation of limit state function for failure probability calculation, a new reliability sensitivity method is presented for limit state function with non-normal variables. The partial differential of the moment of the limit state function to distribution parameters of basic variables is derived. By use of the relationship of the failure probability and the moment of the limit state function, the partial differential of the failure probability to the distribution parameters of basic the non-normal variables is derived furthermore. Hereby, the reliability sensitivity is obtained for the non-normal variables. Compared with the reliability sensitivity based on the first order and second moment method, a logarithm normal illustration is used to demonstrate the rationality and the precision of the presented reliability sensitivity method. At last, the presented method is employed to analyze the partial differential of the failure probability to the parameters of exponential and Weibull distributions.