Research On Multi-attribute Opportunity Maintenance Strategy Of EMU Multi-Component System Based On Disassembly Sequence

With the development of China’s high-speed railway business,the mileage of high-speed railways has reached 35,000 kilometers.Taking high-speed trains has become one of the most important modes of daily travel for the public.Therefore,higher requirements have been placed on the safe operation and maintenance strategies of EMU.Based on the preventive maintenance plan of EMU components,the thesis introduces the opportunistic maintenance risk threshold and constructs the opportunistic maintenance model of system.At the same time,combined with the disassembly theory,the maintenance strategy is further optimized to form an opportunity maintenance plan with low cost,high efficiency and high reliability for the multi-component system.First,in order to formulate a more realistic maintenance strategy for EMU components,introduce the concept of mission success,comprehensively consider the maintenance cost and availability of components,according to multi-attribute decision theory,integrate the above-mentioned decision-making objectives and optimize them into an objective function;and AHP is used to obtain the weight value of each decision-making objectives.The research results show that,compared with the maintenance strategy that takes maintenance cost as a single optimization goal,the maintenance strategy that integrates and optimizes multiple decision-making objectives is more in line with on-site needs.Secondly,the current maintenance system in China is mainly based on the maintenance model of the preventive plan at the component level.Due to the large number of EMU parts and the complicated structure,in order to further improve the system maintenance strategy optimization problem,ontroduce opportunistic maintenance into the existing maintenance model.Based on the hybrid failure rate evolution rules,combined with multi-attribute decision theory,an optimized model of preventive maintenance at the component level was established.On the basis of the component layer,introduce the opportunistic maintenance risk level of components,establish an opportunistic maintenance model that integrates risk thresholds and time windows for opportunistic maintenance,and optimize its maintenance plan.The research results show that the opportunistic maintenance model can effectively reduce the total maintenance cost.Finally,in order to explore the impact of disassembly operations on the system maintenance plan,taking the parts with disassembly relationship in a mechanical system of EMU as the research object,based on the disassembly theory,a disassembly model based on the disassembly mixed graph was established,and plan the optimal disassembly sequence for a single component.A hybrid failure rate evolution rule is used to describe the evolution law of reliability before and after component maintenance.Consider the impact of disassemblycost and disassembly time on the maintenance plan,based on multi-attribute decision theory,a preventive maintenance model at the component level is established.Use the component-level maintenance plan as a basis,the decision threshold was established by taking the opportunity to maintain the risk threshold and time window,the opportunistic maintenance model with the total maintenance cost as the optimization goal.The results of the study indicate that maintenance strategies that consider the impact of disassembly operations are more economical and usable than maintenance strategies that do not consider disassembly operations.