Reliability Analysis of Metro Doors Based on Fault Tree and Monte Carlo Methods

Objective Door system is the most frequently used critical system during vehicle operation, so it is necessary to study its reliability and failure characteristics to ensure the safe operation of urban rail transit. Method Based on the data of door system failure conditions across various Shanghai Rail Transit lines from February 2021 to February 2022, a simulation model based on FTA (fault tree analysis) is established under given state transition rules. Based on this model, the Monte Carlo method is used to simulate the reliability of unknown failure modes: by performing static simulation, the pseudo-random numbers are generated using the linear congruence method to replace real random numbers, and the failure rate of top events and the importance of basic events are calculated; by performing dynamic simulation, the reliability distribution and lifetime sampling values of each component are obtained through multiple distribution fittings; by simulation experiments, the density distribution curves and reliability curves of the system are plotted. Result & Conclusion Numerical results show that，because the failure probability of basic events that obey exponential distribution and Weibull distribution within certain time intervals is very high, thus the system is very likely to fail when it runs into this time interval.