考虑状态模糊性时广义失效概率计算的矩方法

针对失效状态和安全状态具有模糊性的广义可靠性分析问题,提出了一种广义失效概率计算的矩方法。所提方法首先将广义失效概率的积分区域依据功能函数的取值离散化,在离散化的积分区域中,极限状态函数对模糊失效域的隶属函数近似保持为常数,从而将模糊可靠性问题转化为一般的随机可靠性问题,进而可以利用近似的矩方法求得广义失效概率。该文给出了所提方法的实现步骤和原理,算例结果表明所提方法对于中低维问题具有很高的精度和效率。

MOMENT METHOD FOR GENERAL FAILURE PROBABILITY WITH FUZZY FAILURE STATE AND FUZZY SAFETY STATE

For general reliability analysis with fuzzy failure state and fuzzy safety state, moment method is proposed to calculate general failure probability. In the integral operation of the general failure probability, the integral region is scattered according to the value of performance function. In the scattered integral region, the membership function of the performance function to the fuzzy failure region keeps approximately constant, with which the calculation of the general failure probability is transformed into that of the random failure probability. After the transformation from the general failure probability to the random failure probability is completed, moment method is employed to obtain the general failure probability directly. The concept and the implementation of the proposed method are described step by step, and the results of a number of numerical and engineering examples show that the proposed method possesses high precision for low and medium dimension problems.