Research on Reliability Modeling and Maintenance Strategy of Key Component of EMU Based on Stochastic Differential Equation and Copula Theory

Preventive maintenance strategy is an important mean to ensure the reliable operation of large equipment in power plant, nuclear power plant, high-speed railway Electric Multiple Units (EMU) and other fields. Aiming at the problems of high maintenance cost and great damage of EMU gearbox, the reliability and state maintenance decision model based on stochastic differential equation (SDE) and Copula theory was proposed in this paper. Firstly, the model comprehensively considers the degradation process of components and the external random disturbance factors, describes the external random disturbance by Brownian operation, and establishes the Weibull proportional risk model based on SDE. Secondly, based on Copula theory, the reliability model of component performance degradation is obtained. On this basis, the corresponding Time-Based Maintenance (TBM) and Condition-Based Maintenance (CBM) strategies are established, and the preventive maintenance strategy of components is formulated with the optimization goal of minimizing cost ratio. Finally, the example is given to analyze the reliability model and verify its validity.