Research On Joint Life Space Partition And Optimal Maintenance Decision For Multi-unit Systems

Maintenance is an important means to keep a system in its normal and reliable operating condition.However,with the rapid development of modern technology,most systems have become more and more complex that cannot be easy to analyze and now comprise multiple units with various dependencies formed by the interactions of the structures and functions between the components.Therefore,considering the correlation in the study of the optimal maintenance decision for multi-unit systems has become a focus problem.For a system with many identical or different units,the enumeration method is complicated and time-consuming.The high-dimensional model solving is very difficult.In this paper,in order to develop more effective optimal maintenance decision for multi-unit systems with TBM,the main studies are as follows:(1)The deterioration state space partition method is applied to the joint life space partition and modeling for multi-unit systems.The common description and model for multi-unit systems based on opportunistic maintenance policy with TBM is presented and the relationships between them are established.All possible maintenance combinations and their corresponding probabilities are deduced on the basis of analysis of the partition results.(2)The stationary probabilistic density function is defined in multi-unit systems.Further,take a two-unit system as an example,the stationary probabilistic density function is deduced and its numerical solution is developed.Eventually,the numerical experiments verify the correctness and validity of the partition method.(3)Considering the maintenance parameters,the minimization of the average long run cost rate model is developed for the two-unit system and the genetic algorithm is applied to search the optimal threshold.Finally,the numerical experiments and sensitivity analysis are carried out to verify the correctness and validity of the models.