基于马氏距离的竞争失效可靠性分析

为了解决产品退化失效与冲击失效共存的竞争失效下可靠性评估,提出了一种基于马氏距离的评估方法.引入马氏距离将多元退化数据降至一元马氏距离,采用具有随机影响的Wiener过程进行退化建模.研究了泊松过程以及固定时间发生的两类极端冲击过程,建立了同时考虑变阈值和最小冲击幅值的相关竞争失效模型.采用裂纹增长案例验证了所提方法的有效性,敏感性分析评估了模型参数对产品可靠性的影响.结果表明泊松过程冲击和固定时间冲击都对产品可靠性水平的分析值产生影响.

Reliability Analysis for Competing Failure Based on Mahalanobis Distance

A reliability analysis method based on mahalanobis distance (MD) was proposed for the reliability evaluation at competing risk involving both degradation-based failure and shock-based failure. Firstly, MD was used to transform the multivariate degradation data to one dimensional MD data, and the MD data was modeled by Wiener process with random effects. Then, two extreme shock processes were considered, the shock processes with Poisson process and the shock processes with a fixed time. The reliability models of the two situations were established respectively. Both the shift threshold and minimum magnitude of shock loads were considered synchronously in these dependent competing failure models. Finally, the effectiveness of proposed models was demonstrated by a fatigue crack increase example. Besides, sensitivity analysis was performed to assess the effects of model parameters on the reliability. Results show that, both the shocks with Poisson process and with a fixed time affect the analysis results of product reliability.