考虑失效模式相关性的机械系统可靠性分析

考虑失效模式相关性对机械系统可靠性的影响,提出了一种基于FORM(first order reliability methods)近似的系统可靠性分析方法及其实施流程.采用FORM计算系统各失效模式的可靠度和灵敏度,在此基础上,获得用于衡量失效模式相关性的相关系数矩阵.将系统可靠性模型求解转化为多维正态积分计算,进而采用高效的近似方法获得系统可靠度.给出失效模式灵敏度和随机变量灵敏度的定义及其相应的计算方法.算例结果表明:该方法能够获得较为准确的系统可靠度,且具有较高的计算效率,能够有效识别关键失效模式和随机影响因素.

Reliability Analysis for Mechanical System with Correlated Failure Modes

To evaluate the effect of failure mode correlations on the mechanical system reliability， a system reliability analysis method and its implementation procedures were proposed based on FORM approximation. FORM was used to calculate the reliabilities and sensitivities of all the failure modes in the system， and then the failure mode correlation coefficient matrix for determining how they are correlated was obtained. The solving of the system reliability model was converted to the integration of multivariate normal distributions， and the efficient approximation algorithm was used to get reliability degree. The definition of failure mode sensitivity and the corresponding calculation method were proposed based on the numerical difference， as well as the definition of random parameter sensitivity and its calculation method through the composite derivative theorem. The results demonstrated the efficiency of the proposed method for quantifying the mechanical system reliability with failure mode correlations， and also the feasibility for identifying the key failure modes and random parameters.