The Reliability Model And T-S Polymorphic Fault Tree Of The Bogie System

With the fast development of high-speed railway vehicles,both the running speed and the usage of the EMU are increasing,which highlights the reliability and the maintainability of its operation.As an essential part of the EMU,the reliability of the bogie has a great influence on its running safety.However,there are relatively few systematic reliability analyses on bogies,and the existing evaluation methods are not comprehensive enough.Therefore,this thesis mainly studies the reliability of the bogie system from the aspects of system and component failures,using reliability model and fault tree model respectively.Firstly,the reliability model of the bogie system is established from the systematic analysis.Based on the configuration and function of the bogie system,the topological structure of the bogie is constructed,and the reliability model theory is introduced,combined with the simulation results under the damper fault,then the task reliability model and basic reliability model of the bogie system are obtained,which provides a theoretical basis for the reliability evaluation of the bogie.Secondly,starting from the component failures,the T-S polymorphic fault tree of the bogie system is set up according to the T-S polymorphic fault tree theory.Based on the configuration of the bogie and the maintenance regulations of the EMU,the fault states of the event are divided,and the actual meaning of each state of the event is given,then the T-S fault tree diagram illustrates the correlation between each event.Additionally,the logical relationship between events is expressed by T-S logic gates,through which the degree of impact caused by the failure of each component or subsystem of the bogie is studied.Finally,by applying the Bayesian network theory,the T-S polymorphic fault tree of the bogie system is transformed into a faulty Bayesian network.Through the advantages of the two-way reasoning of Bayesian network,the posterior probability and key importance of each event are calculated.At the same time,the wheelset system is set as an example to be programmed in MATLAB.The results illustrate that the use of faulty Bayesian network analysis method has an important reference value for optimizing the process and frequency of bogie maintenance and improving the efficiency of bogie maintenance.