可靠性灵敏度分析的一种新方法

 基于极限状态函数矩估计的失效概率计算,提出一种新的可靠性灵敏度分析方法。推导极限状态函数的矩对基本变量分布参数的偏导数,并进而利用失效概率与极限状态方程矩的关系,推导失效概率对基本变量分布参数的偏导数,从而得到可靠性灵敏度。与改进一次二阶矩可靠性灵敏度分析方法相比,所提方法不用求极限状态方程的设计点,因而不需用到极限状态函数对基本变量的梯度函数,适用于隐式极限状态方程的可靠性灵敏度分析,算例结果也充分显示所提方法的合理性和精度。

A New Reliability Sensitivity Analysis Method

Based on the moment estimation of limit state function for calculation of failure probability,a new reliability sensitivity analysis method is presented.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 variables is derived furthermore.Hereby,the reliability sensitivity is obtained.Neither design point nor gradient of the limit state function to the basic variable is required for the presented method,therefore it is more suitable for the implicit limit state equation comparing with the reliability sensitivity based on the first order and second moment method.Some illustrations are used to demonstrate the rationality and the precision of the presented reliability sensitivity analysis method.