Research On Opportunistic Maintenance Decision-Making Method Of Electric Multiple Unit System Considering Resource Constraints

The rapid development of rail transit has greatly improved the efficiency of railway operation in China.From 2018 to 2022 alone,China ’s railways transported 13.2 billion passengers,of which electric multiple unit(EMU)undertook extremely important transportation tasks.In order to ensure the safe and efficient operation of EMU and meet the increasingly frequent travel needs of passengers,it is extremely necessary to formulate a scientific and economical maintenance strategy.Considering that there are many correlations between components in the EMU system,the introduction of opportunistic maintenance concept can effectively improve its operation efficiency and maintenance economy.At the same time,human resources and spare parts resources,as the main resources to ensure the smooth implementation of the maintenance tasks of the EMU system,also need to adopt practical configuration strategies to conduct in-depth analysis.Therefore,this paper studies the joint decision-making of opportunistic maintenance strategy and maintenance resource allocation strategy of EMU system.Firstly,in order to improve the economy of EMU opportunistic maintenance strategy,an opportunistic maintenance strategy based on dynamic time window is proposed.Based on the economic correlation of each component,this strategy introduces the concept of opportunistic maintenance to merge the maintenance timing of each component.Taking the downtime of the traditional opportunistic maintenance strategy as the trigger condition,the reliability utilization value and the delay penalty cost are introduced to construct the opportunistic maintenance downtime optimization model,and the dynamic time window is realized.The example analysis shows that the opportunistic maintenance strategy based on dynamic time window can effectively reduce the total maintenance cost compared with the traditional opportunistic maintenance strategy,improve the economy of the opportunistic maintenance strategy,and provide some theoretical support for the maintenance decision of the EMU system.Secondly,the joint optimization decision of opportunistic maintenance and human resource dynamic configuration based on dynamic time window is established.Considering the difference between maintenance tasks and downtime and the constraints of limited human resources,the dynamic allocation method of human resources is used to select limited maintenance personnel,and then the number of maintenance personnel and the threshold of opportunity maintenance are taken as decision variables,and the total maintenance cost is taken as the goal to optimize.The example analysis shows that compared with the traditional opportunistic maintenance model and the fixed maintenance personnel maintenance model,the proposed model realizes the dynamic configuration of maintenance personnel,saves the total maintenance cost,reduces the downtime,and further optimizes the economy and application efficiency of the opportunistic maintenance strategy.Finally,the joint optimization decision of opportunistic maintenance and(S,s)strategy based on dynamic time window is established.The strategy introduces a two-level imperfect maintenance method,uses the cost-effectiveness analysis method to make a choice,determines the number of spare parts consumption based on the number of maintenance parts,and divides the spare parts ordering strategy into three situations according to the existing inventory.A joint optimization decision is proposed,which takes the opportunity maintenance window,the maximum inventory and the safety inventory as the decision variables,and the minimum total cost during the maintenance planning period as the optimization goal.The iterative method and enumeration method are used to solve the strategy.The example analysis shows that the two-stage imperfect maintenance mode in the opportunistic maintenance strategy has better economy than the single-stage imperfect maintenance mode.At the same time,the safety inventory and maximum inventory in the spare parts inventory strategy are optimized,and the joint optimization of the opportunistic maintenance strategy and the spare parts inventory strategy is realized.