| With the rapid development of high-speed EMUs and the continuous improvement of their running speed,higher and higher requirements are put forward for the safety of EMUs.In order to ensure the safe operation of EMU and improve the reliability of EMU components,it is necessary to make reasonable maintenance plan for EMU components.In addition,there are few studies on the maintenance mode of EMUs’ equipment since they were put into use.Therefore,This paper is based on the preventive maintenance theory and considering the influence of external environment and risk on maintenance mode,this paper carries out a mathematical modeling and Simulation Study on preventive maintenance strategy of EMU components considering external factors.The research results are expected to provide some reference for EMU to make maintenance plan decision and on-site maintenance.Firstly,the proportional failure rate model is introduced,and the mathematical model of low-level maintenance strategy for EMU components considering external environment is established.By using Monte Carlo simulation method and optimizing the total maintenance cost rate,the optimal maintenance plan of EMU components in the whole low maintenance cycle is obtained.The results show that the low-level maintenance plan considering the external environment makes the components of EMU more reliable and less maintenance times,and meets the requirements of maximizing economic benefits on the premise of ensuring the safe operation of equipment.Secondly,aiming at the current multi-level maintenance system of China’s EMUs,this paper is combining with the two-level imperfect maintenance strategy model,taking the components that need to be repaired or replaced during the four-level maintenance of CRH EMUs as the research object,the mathematical model of multi-level maintenance strategy considering the external environment in its maintenance cycle is established.The results show that the mathematical model has the optimal solution and is within the ideal reliability threshold range,thus the optimal maintenance plan can be obtained.In addition,the study found that considering the optimal maintenance plan of the external environment,the reliability threshold of the equipment is higher.which is in line with the actual situation.Finally,considering that the operating environment of EMU components is complex and there are many influencing factors,the maintenance plan only considering a single factor can not fully meet the actual maintenance status of EMU components.For this reason,a preventive maintenance strategy model for EMU components considering both external environment and fault risk is established.By introducing the fault risk factor,the safety risk,the risk of train delays and the severity of the fault are evaluated.The results show that the reliability threshold of the model is 16%higher than that of the sequential preventive maintenance model. |
