Reliability Study Analysis Of Bogie System For Metro Trains

As a transportation mode with the largest carrying capacity in urban rail transportation,metro features fast speed,short train interval time,large carrying capacity,punctuality and efficiency,and low influence by environmental factors.These all make it significant for the relief of urban ground transportation pressure and social and economic development.As China’s urban metro operation mileage continues to grow,an increasingly number of metro trains are put into operation.As a result,the efforts to safeguard the safe and reliable operation of metro trains have become one of the core issues for metro development.As the core subsystem of the train,the bogie system plays a key role in carrying and transmitting various loads,damping and buffering,and guiding,etc.Whether the bogie system can work normally and smoothly poses a direct impact on the safety of the train.Hence,it is of great significance to study the reliability of the bogie system to ensure the safe and reliable operation of the metro train.In this paper,the reliability of the bogie system of Guangzhou metro train was analyzed and studied.The main points of the study are as follows.(1)The reliability study was carried out from the perspective of metro train bogie design.By applying FPMA method,the structural composition,working principle,functional logic relationship and performance of metro train bogie system were analyzed in depth.The key components were identified and margin analysis of key components was carried out to study the essential safety and reliability of each structural component of the bogie from a design perspective.(2)Reliability calculation from the perspective of metro train bogie operation: by employing the collected historical failure data of metro train bogie,a failure distribution model fitting study was performed for the bogie based on the component level to determine the operational reliability characteristic function of key components and obtain the probability of component failure at different time points.(3)To address the problem of incompleteness and uncertainty of objective small sample data,predicated on the failure probability determined by the fault distribution fitting,subjective empirical data obtained by experts in the field on the probability of failure of each component at specific time nodes were introduced.The subjective and objective data were fused by using evidence theory to obtain the multi-source fusion failure probability of each key component of the bogie system.This made full use of the multi-source reliability data information and solved the problem of cognitive uncertainty caused by small sample data.(4)The reliability of the bogie system of metro trains was studied in a deepgoing way,and a fault tree was established and transformed into a Bayesian network model.The failure probability obtained from the fusion of multi-source reliability data was used as the prior probability of the root node of the Bayesian network model.The posterior probability and the importance and sensitivity ranking of key components were inferred by the joint tree algorithm of Ge NIe software to identify and the weak points of the system.(5)The design reliability analysis and the application reliability analysis of the metro train bogie system were conducted respectively.The application reliability analysis results were fed back to the design reliability analysis,so as to dig deeper into the causes of the weak parts of the system,and to find out the shortcomings of the existing design of the bogie system.For good measure,reasonable suggestions were proposed for improving the design reliability of the system,as a way to make the design reliability and operational reliability support each other.In this way,the inherent reliability of the bogie system was enhanced,thus improving the operational reliability of the system,and ensuring the safe and smooth operation of the metro trains..