基于退化相关性分析的竞争失效系统可靠性模型

Reliability Model of Competing Failure System with Dependent Degradation

复杂系统失效往往受多个退化过程及外界冲击的影响,属于竞争失效过程。为分析此类系统可靠性同时考虑冲击过程对退化过程的影响、不同退化过程间的相关关系和冲击导致不同退化过程退化突增量之间的相关关系,基于Gamma过程和Copula函数建立系统竞争失效可靠性模型,并提出相应的可靠性近似模型以简化计算。在此基础上,给出相关模型的参数估计和Copula函数选择方法。以微型发动机为例对系统可靠性近似模型进行检验,并分析相关性参数对系统可靠性的影响。案例结果验证了可靠性近似模型的精确性,表明退化相关性对系统可靠度有直接影响,在退化故障为主要故障模式的系统可靠性分析中需要充分考虑退化相关性。

Failure of complex systems is often affected by multiple degradation processes and external shocks,and is a competing failure process.To analyze the reliability of such systems,the influence of shock process on the degradation process,the dependency of different degradation processes,and the dependency of the sudden increments of degradation caused by shock are considered simultaneously,and the system reliability model with competing failure is derived based on Gamma process and Copula function,and then an approximate reliability model is proposed to simplify the calculation.On this basis,the parameter estimation and Copula function selection methods are presented.The approximate model of system reliability is tested by taking micro-engine as an example,and the influence of dependency parameters on system reliability is analyzed.The result verifies the accuracy of the approximate reliability model,and illustrates that the dependent degradation has direct influence on the system reliability.Thus,for the system that degradation failure is the dominant failure mode,the dependent degradation should be considered seriously in reliability analysis.