Reliability Analysis And Optimization Of Metro Bogie Frame

With the rapid development of urban rail transit,subway has become the preferred transportation scheme for people’s daily urban travel,which puts forward higher requirements for the performance of metro vehicles.As the main force bearing component,bogie frame is one of the key components to ensure the safety of vehicle operation,which plays a decisive role in the safety,stability and reliability of vehicle operation.Therefore,based on the reliability theory,combined with the finite element analysis and dynamic stress test,the reliability analysis and optimization design of a metro vehicle bogie frame are carried out.The main research contents are as followsFirst,the structural performance of bogie frame is analyzed.The finite element model of bogie frame is established by Hyper Mesh software,and the strength analysis is carried out based on UIC615-4 and en13749 standards;The Goodman fatigue limit diagram is used to evaluate the fatigue strength of the weld area with large stress;The first eight modal shapes and natural frequencies of the frame are obtained by modal analysis.Through the above finite element analysis,whether the structural performance of bogie frame meets the requirements is verified.Second,the multi-layer cross entropy method is used to analyze the static strength reliability of bogie frame.Based on the importance sampling function,a multi-layer cross entropy reliability analysis method is proposed.The accuracy and efficiency of the method are verified by comparing with Monte Carlo method;Secondly,the parametric modeling of bogie frame is carried out,with structural stress as the output variable and structural plate thickness as the input variable,the central composite test design is carried out,and the high-precision response surface model is fitted;Then,the static strength reliability of bogie frame is analyzed by using multi-layer cross entropy method.Third,the dynamic stress test of bogie frame is carried out to analyze the fatigue reliability.According to the above analysis results,the layout scheme is determined,and the stress time history of the frame is obtained through the action stress test,and the equivalent stress amplitude of each measuring point is obtained through data processing;The probability distribution function is obtained by fitting the data of each measuring point,and the fatigue reliability of bogie is obtained by random sampling 10000 times and probability statistics.Finally,the cross entropy optimization method is used to optimize the bogie frame design.Firstly,test function is used to verify the accuracy of cross entropy optimization algorithm,and then static strength response surface function is used as the objective function to optimize the design of bogie frame.Under the same condition,the static strength,fatigue strength and static strength reliability of the optimized frame model are calculated again.The optimization results show that the stress of bogie frame structure is reduced and the reliability is improved,which is in line with the expected optimization goal.