Lateral Stability Analysis And Optimization Of High-speed EMU Bogie

The lateral stability of high-speed EMU is related to the stability and safety of vehicle operation,and is greatly affected by wheel wear.Therefore,it is very important for the safe and stable operation of high-speed EMU to analyze the influence of wheel wear on lateral stability and improve the lateral stability.This paper takes a high-speed EMU in China as the research object,and uses multi-body dynamics theory,wheel-rail contact theory and wear theory to establish vehicle system dynamics model and wheel wear prediction model.The influence of wheel wear on lateral stability,running stability and curve passing performance is analyzed,and the robust optimization design of suspension parameters is carried out to improve vehicle dynamic performance.The main research contents are as follows:The vehicle system dynamics simulation model of a high-speed EMU is established by using SIMPACK software.The line geometry model is established based on the data of a high-speed railway.The ballastless track irregularities of high-speed railway are used as wheel-rail excitation.The accuracy of the simulation model is verified by comparing with the line comprehensive test data.The vehicle dynamic performance under different lines and speeds is analyzed to ensure the safe and smooth operation of the vehicle and lay the foundation for the subsequent wheel wear and suspension parameters optimization.In order to study the influence of wheel wear on lateral stability,a wheel wear prediction model of high-speed EMU is established based on wheel-rail contact theory and Archard wear model.The reliability of the prediction model is verified by the measured wheel wear data.The wheel wear profiles with different operating mileages are selected to match with the new rails,and the wheel-rail contact relationship and equivalent taper change laws are studied to determine reasons for the deterioration of vehicle dynamic performance.The vehicle dynamic performance under different lines,wheel wear profiles and speeds is analyzed,and the vehicle dynamic performance with significant changes is determined and optimized as the objective function.In order to reduce the influence of uncertain factors on vehicle dynamic performance,grey fuzzy Taguchi method and response surface method are used to carry out robust optimization design of suspension parameters.Through sensitivity analysis,the suspension parameters with greater influence on vehicle dynamic performance are selected as design variables.The parameter design is completed by the grey fuzzy Taguchi robust optimization design method,and the optimal parameters combination is determined according to the multiperformance characteristic index.The response surface robust optimization model is established with the normalized suspension parameters as the design variables and the maximum signal-to-noise ratio as the optimization objective.The robust optimization model is optimized by using Non-dominated Sorting Genetic Algorithm II to obtain the optimal suspension parameters combination.By comparing with the mean value and signal-to-noise ratio of vehicle dynamic performance before optimization,it is verified that the proposed methods can effectively improve the vehicle dynamic performance and robustness.In this paper,the influence of wheel wear on vehicle dynamic performance is investigated,and the research results provide some reference for the maintenance and optimization of wheel profile of high-speed EMU.Two methods are used to optimize the suspension parameters robustly,which provides a new idea for improving vehicle dynamic performance.