Research On Dynamic Maintenance Strategy Of Electric Multiple Unit Multi-component System

With the launch of the Chinese standard EMU,it marks that EMU in China achieved a new stage from "made in China" to "created in China" in the R & D design and manufacturing technology.As EMUs are technology-intensive high-end equipment,the effectiveness of their maintenance plans and the scientific nature of their maintenance strategies directly affect the reliability and efficiency of high-speed EMUs.In particular,the number of EMUs currently entering the advanced repair stage continues to increase,which brings huge challenges to the EMU maintenance department.Therefore,in order to further optimize the maintenance plan,in view of the shortcomings that the static maintenance strategy can’t adapt to the fluctuation of passenger flow and operation plans,the dynamic maintenance plan of EMU was established under the influence of traffic volume changes,and the maintenance cost of EMUs was further reduced under the premise of ensuring the reliability requirements.The specific research content of the paper is as follows:First of all,in order to explore the economics of EMU component maintenance strategies under the influence of uneven passenger flow distribution,the polynomial fitting method was introduced to segment quantify wave passenger flow,and the cost function of component differential shutdown loss under the influence of uneven passenger flow distribution was also proposed,based on the accelerated failure time model,dynamic adjustment method of component maintenance plan with reliability as constraint was established,through the sensitivity analysis of the delayed maintenance reliability threshold of components,the most economical maintenance strategy adjustment method was determined.Moreover,based on the dynamic maintenance model of single component,the component cost model that takes into account the demand for transportation volume was constructed.Based on the evolution law of single component failure rate / reliability under the influence of fluctuations in transportation volume,the optimal maintenance plan at the component level was obtained through cost optimization.The dynamic grouping method based on rolling horizon approach was introduced,and the group maintenance adjustment cost of component considering the impact of traffic demand was set up.Based on the component maintenance adjustment range,the optimal grouping scheme and grouping savings within the plan horizon was obtained,the multi-component dynamic grouping model within a single maintenance planning time window was constructed.The maintenance grouping plan was dynamically updated through plan horizon rolling to adapt to changes in traffic demand.Lastly,in order to discuss the group maintenance strategy of EMU complex systems under the influence of different traffic demands,the fault-related transfer process between components was analyzed based on the fault chain theory.The correlation coefficient matrix was used to quantify the component fault correlation,and to establish the component reliability decline under the impact of failure dependence.In the maintenance plan horizon,based on economic correlation and dynamic grouping method to combine component maintenance activities,the impact of fault correlation on maintenance cost savings during dynamic grouping of components was further explored.The conclusion shows that taking into account the dependence of components when combining maintenance activities can effectively save maintenance costs.