Study On Urban Rail Vehicle Brake System Reliability Modeling And Simulation

The complex and time-varying urban rail vehicle brake system failure is theroot cause of train caused a major accident. Internal elements, structuralrelationship, external properties and the variation of brake system complete withthe specificity and uncertainty. Its failure modeling analysis is the difficult issuesin international research. The existing failure modeling methods exist someshortcomings such as difficult to match model and verify, not effectively dealingwith the failure randomness and the evolution of uncertainty.In this paper, on the basis of the degree of failure and hazard and the levelof security of urban rail transit vehicles braking system determined, commoncause failure, no failure data, and failure correlation and recovery of eachsubsystem internal failure and each other are studied. The failure channels ofdistribution the failure characteristics are revealed of unit components andsubsystem of braking system. The GO-Small Sample theory is put forward, shortfor GO-SS method. Failure characteristics are excavated amount of a very smallsample of the test and field data, to create hybrid reasoning and systematicreliability model of urban rail vehicle brake system, to seek its fast parsingalgorithm, and to extract the security confidence and trends.This paper focuses on the reliability modeling and simulation of thebraking system to carry out the following studies:1Starting from failure to the cell-level components, the reliabilityevaluation method of brake key components is carried out in a small sample data.The failure rate is estimated by multilayer Bayesian estimation in no failure data.Combined with maintenance time obeying lognormal distribution in the smallsample, mean time between repairs parameters are estimated.2GO-SS method of system-level reliability modeling is proposedcombined with the small sample theory and reliability analysis of GOmethodology. The equivalent reliability parameters of closed-loop repair systemand two failure modes parts are analyzed, when the brake air system divided intoeight subsystems according to its works. So the systematic braking system reliability model is established. The quantitative and qualitative analysis of thisrepairable system reliability are completed, and then repairable system reliabilitycharacteristics and minimal cut sets in the steady-state case are got. At last theimpact of common cause failure is taken into account of system unavailability,so brake system failure probability chart is get.3An improved monte carlo sequential method is using for the simulation ofurban rail vehicle brake system reliability. For the failure modes and failureduration of system, the actual failure process of brake component is simulated tobuild its reliability index and give a general method for solving simulation. Theresults validate the correctness of parsing algorithm of the system downtimeprobability.The exploration and practice of urban rail vehicle brake system reliabilitymodeling and simulation provide theoretical support for the safe operation ofour rail trains and supply a scientificbasis for the establishment of the EMU trainbraking system design and the maintenance management system credibility, forthe reference method of the complex time-varying system reliability analysis.