Reliability Modeling And Maintenance Strategy Optimization For Systems With Main And Auxiliary Components Under Imperfect Inspection

With the advent of industry 4.0 era,a series of technologies such as sensor technology and Internet of things have developed rapidly,which not only brings convenience to daily production and life,but also brings new opportunities and challenges to reliability research.The progress of inspection technology makes the system state data easier to obtain,which is conducive to the development of condition-based reliability research.However,in practice,due to technical limitations and environmental impact,there are usually errors in inspection,such as inspection errors caused by improper operation of operators and measurement errors of inspection equipment.Ignoring these errors will lead to decision-making errors and even serious consequences such as property and life safety losses.In addition,the imperfection of inspection will also cause deviation to reliability evaluation and analysis.Therefore,the study of system reliability under imperfect inspections has important theoretical and practical significance.Inspired by practical problems,this paper takes the systems with main and auxiliary components as the research object.The system includes critical subsystems and auxiliary subsystems.The critical subsystem with main components is responsible for completing the system function.Once the subsystem fails,the whole system will fail;The auxiliary subsystem is used to protect the critical subsystem from environmental impact,so as to ensure that the system operates in a relatively stable state.The failures of the subsystem will not directly lead to the failure of the whole system.This paper establishes the reliability and maintainability models under imperfect inspections by using the methods of probability theory,recursive method,semiregenerative process theory and numerical simulation,which provides a method for finding the optimal maintenance strategy.The main research work of this paper is as follows:Firstly,taking the systems with one component in both the critical subsystem and auxiliary subsystem as the research object,the reliability model of systems under imperfect inspections is constructed.The reliability indexes of the system,such as reliability function and distribution function of the first failure time,are derived by recursive method.The correctness of the derivation results is verified by a numerical example and system simulation,and the influence of inspection quality on system reliability is studied by sensitivity analysis method.Secondly,for the system mentioned above,considering corrective maintenance and preventive maintenance strategies,the inspection and maintenance model under imperfect inspection is constructed,the periodic inspection optimization problem is proposed,and the optimal solution is given.The long-run average cost of the system is derived by using the semi-regenerative process method and aiming at minimizing the average cost of long-term operation,the inspection period is optimized.The optimal inspection policy of the system is obtained by enumeration method.The impact of different maintenance on the cost is studied through comparative research.Thirdly,based on the above researches,the model is further extended by considering that the auxiliary subsystem contains multiple components.For one thing,system with multiple components in auxiliary subsystem is modelled.For another,the optimization problem of preventive maintenance strategy is constructed.The long-run average cost of the system is derived by the semi-regeneration process method.Aiming at minimizing the long-run average cost of the system,the maintenance thresholds of the main component and the auxiliary subsystem and inspection period are optimized.The optimal preventive maintenance strategy is obtained by enumeration method.What’s more,the correctness of the results is verified by simulation.This paper aims to solve the problem of reliability modeling and maintenance strategy optimization of systems with main and auxiliary components under imperfect inspections,which enriches and expands the research content of reliability of systems with main and auxiliary components to a certain extent.It has important theoretical and practical significance for reliability modeling,evaluation and analysis of dependent multi-component systems and the decision and optimization of inspection and maintenance strategy under imperfect inspections.