Optimization Of Maintenance Strategy For EMU Based On Life Cycle Cost And Reliability Assessment

With the increase of the Electric Multiple Units(EMU)allocation number,the maintenance workload and maintenance costs are also increasing annually.Meanwhile,the existing maintenance strategy cannot well meet the actual needs of EMU operation and maintenance.From the perspective of Life Cycle Cost(LCC),the unit price of EMU purchase is high,but the subsequent operation and maintenance costs are higher.Furthermore,the cost pressure brought by EMU maintenance has begun to appear.From the perspective of reliability,EMU,as a large-scale complex equipment of mechatronics,should take targeted maintenance measures based on the reliability characteristics of various systems and components.Therefore,based on the perspective of life cycle cost and reliability assessment,this paper studies the optimization of EMU maintenance strategy,considers economy and reliability,and ensures that EMU achieve the minimum life cycle cost under the premise of safety and reliability.In this paper,locomotive and vehicle maintenance theory,life cycle cost theory,reliability and maintenance engineering,mathematical statistics and MATLAB software application are involved in.The following aspects were mainly studied:(1)The life cycle cost model and maintenance cost model of the EMU were constructed,and the LCC estimation was carried out.It was found that the maintenance cost during the life cycle accounts for 40.2% of the LCC of the EMU,which was 2.3times higher than the purchase cost.The sensitivity analysis was carried out,and two types of sensitive factors affecting the LCC were identified,and on this basis,a maintenance strategy optimization scheme of EMU was proposed to extend the cycle interval and reduce the unit price of advanced maintenance.(2)The reliability model of EMU was established,and the traction system was taken as an example to further decompose,and the specific reliability calculation formula was given.The specific process and method of EMU reliability evaluation were clarified,then the reliability of components and the whole vehicle was evaluated according to the fault data.Based on the goal of minimum test sample and minimum test mileage,the reliability verification scheme was given,which demonstrates the rationality and feasibility of extending the cycle interval.It also reflects the practicality of LCC technology in the optimization process of EMU maintenance strategy.(3)The analysis identified two main factors that affect the unit price of advanced maintenance.Based on the qualitative reliability analysis and the purpose of reducing the LCC of EMU,the specific decision-making optimization method of maintenance strategy was proposed,and a case analysis was carried out by taking the traction system as an example.The feasibility of the scheme was demonstrated from the theoretical level,and it can provide a certain reference for the specific decision-making optimization of the maintenance strategy from the perspective of LCC.