Availability and reliability of system with dependent componentsand time-varying failure and repair rates

摘要

System reliability depends not only on the reliabilities ofncomponents in the system but also on their interactions. Generally, in ansystem, not only s-independent failures but also s-dependent failuresnamong components can occur; thus there are many studies where thens-dependencies among components are taken into account in systemnreliability and availability analysis, but in which the failure andnrepair rates were assumed constant. Whereas, from a practical viewpoint,nthe constant failure rate assumption for components has been, and isnrepeatedly challenged by knowledgeable reliability practitioners.nTherefore, there are other studies which handled the problem ofntime-varying failure rates, among which all concerned repairable systemsndid not involve s-dependent failures. In most cases, however, to combinens-dependent failures and time-varying failure and repair rates in systemnreliability and availability analysis is the most appropriate for realnsystems. But it is very difficult to obtain the analytic solution and,nin most cases, the closed-form solution for system reliability andnavailability does not exist, so that numerical or simulation methodsnmust be used. This paper studies one kind of system that enduresnenvironmental shocks, and where one or more components can failnsimultaneously due to a cumulative shock-damage process. An approach fornreliability and availability analysis of such kinds of repairablensystems is presented, where failure and repair rates of components cannbe varied with time. One type of special vehicle with such mechanicalnsystems illustrates system reliability and availability solutions