Research On Phased-mission Systems Reliability Analysis,Redundancy Allocation Optimization And Maintenance Strategy

The phased-mission system is widely used in large and complex equipment such as aerospace and automobile.The completion of the functions of large-scale and complex equipments is often composed of a series of phase tasks.For example,the attack task of missile is divided into three stages: launching,inertial guidance and terminal guidance.In different task phases,the system composition and component configuration of the phased-mission systems are different.In addition,the sharing of components exists in different phases or between phases,which makes PMS in reliability modeling and analysis,redundancy allocation optimization and maintenance strategy become more complex compared with a single-phase system.This article studies PMS from the following aspects:1)The modeling of phased-mission systems is difficult and the solving process is complex because of the relevance of the phase tasks and the sharing of components existing in different phases or between phases.To solve the problem,based on the chain rule and the conditional independence rule of Bayesian networks theory,the path sets combination method of phased-mission systems is proposed.Aiming at the problem of the cross-stage correlation of components and its different failure rate in each phase,the Cumulative Exposure Model considering the historical damage of components is used to solve by obtaining the cumulative damage distribution of each component in each phase.In view of the same failure rate in each phase of the component,a conditional residual life model is used to describe the component cross-stage correlation.The path sets combination method of phased-mission systems method avoids the large conditional probability table?large storage and large computation problems caused by the excessive discrete states in the traditional Bayesian method and the problem that the PMS-BDD method has strict requirements for variable ordering and is difficult to solve the system reliability with multiple failure distribution types of components.In the end,a phased-mission systems reliability modeling and solving is carried out for a geosynchronous orbit satellite,and compared with the PMS-BDD method,which verifies the correctness of the method.2)The literature on the optimization of the PMS redundancy allocation does not consider the sharing of components between stages,redundancy sharing,and the uncertainty of component prices and failure rates.In this paper,three PMS redundancy allocation optimization models are proposed based on the road set combination method.Model?considers component sharing,model?considers component sharing,and redundancy sharing and model ? considers component sharing,redundancy sharing,and the uncertainty of component failure rate.It is verified by examples that adopting phase redundancy sharing can significantly reduce system cost without reducing system reliability.When using a robust optimization model that takes into account uncertainties,the system can effectively suppress the impact of changes in the design variables on the system when there are changes in the design variables.3)PMS is essentially a multi component system composed of multiple components.Based on this view,the multi component opportunity maintenance strategy is optimized for PMS.The path sets combination method and the dichotomy method are used to obtain the best opportunity maintenance plan that meets the system's minimum reliability requirement.The maintenance strategy aims at the overall PMS minimum maintenance cost.The example results show that the opportunity maintenance strategy reduces the maintenance cost by 26.9% compared to the individual component maintenance strategy.