Research On Urban Rail Transit Vehicle Brake System Analysis Methodology

The operation safety and security of urban rail transit has become an important issue currently, while it's developing rapidly. As the carrier, the urban rail transport vehicle, the security situation of which is not optimistic, has always gone wrong and caused accidents, because of its high speed, large capacity and complex environment. These failures will not only seriously affect the normal operation, but also cause accident which will lead huge casualties and economic losses. The brake system, as the key system of urban rail transit, directly affects the safe operation of vehicles. To improve the safety of vehicle operation, making brake system safety analysis, discovering the fault state laws and safety features, and evaluating the state prediction, are effective early-warning security measures.This paper focuses on the safety analysis of brake system and has made the following studies:1.According to the existing problems of urban rail traffic vehicle braking system safety analysis, the paper put forward a comprehensive safety analysis method named as GO-Bayes method, based on GO method which is used for reliability analysis and reasoning theory. The basic conception has been systematically expounded, which involves structure two-sides modeling, information fusing of a variety of fault with Bayes theory, reliability analyzing based on system model and reverse reasoning of fault. The way of the system modeling analysis and process are summarized.2. Application analysis of urban rail transit vehicle brake system is made based on GO-Bayes method. The system graph model is established based on the architecture theory and fault information of system. The reliability and the security of system architecture are analyzed and quantitative and qualitative analysis is completed. The normal probability and inverse probability of the system is calculated, while minimal cut sets are obtained. Probability assessment of the current state of system is made considering detection information.3. The application process of simulation safety assessment of urban rail transit vehicle brake system is studied with Monte Carlo methods. The simulation model of normal probability calculation based on GO-Bayes model of system is established and the simulation result has verified the analytical method. The trends prediction assessment of system reliability and safety are simulated based on components' reliability, separately as first pre-fault time of the system and fault-repaired system which is with parts updated. The state forecast of the system in long-term operation has been researched.