Research On Weight Lightening Of A-type Metro Aluminum Alloy Car Body Structure

With the continuous development of urban metro transportation in China,the lightweight design of car body of metro vehicles has become increasingly important.This is because the reduction of the weight of the car body is beneficial to improve the running speed of the metro train,increase the passenger capacity,and reduce the manufacturing and operating costs.After the lightweight design of car body,the stiffness and natural frequency of car body may be reduced,so that car body is more likely to resonate when subjected to excitation from the line or other aspects.If the vibration exceeds a certain limit,it will affect the running quality of vehicle and the ride comfort of passengers.For this reason,this paper carries out an research on weight lightening of the car body without reducing the stiffness and natural frequency.This paper describes the current status of lightweight research on car body of rail vehicles at home and abroad in recent years.Taking the aluminum alloy car body of a type A metro vehicle as the research object,on the basis of fully understanding its structural characteristics,the car body structure is simplified reasonably,and the finite element model of the car body is established.The finite element simulation analysis of the strength,stiffness and mode of the car body is carried out,and the performance of the car body is checked according to relevant standards.It can be seen that the performance of the car body meets the requirements of standards.On the basis of the performance analysis of the car body,the plate thicknesses of the car roof,side wall,and underframe side beam are taken as the design variables,and a two-step optimization strategy is used to carry out the lightweight research on the car body.In the first optimization,based on the analysis of mass sensitivity,stress sensitivity,displacement sensitivity and relative sensitivity,the design variables are classified and the range of variation of various types of the design variable values is adjusted.To reduce the weight of the car body is taken as the optimization purpose,the car body is optimized.The first optimized car body is taken as the research object.Based on the analysis of mass sensitivity,modal frequency sensitivity and relative sensitivity,the design variables are reclassified and the range of variation of various types of the design variable values is adjusted.To increase the natural frequency of the car body in the preparation status is taken as the optimization purpose,the car body is optimized for the second time.After two optimizations,the weight of the car body is reduced by 335kg,the stiffness of the car body and natural frequency of the car body in the preparation status remain basically unchanged,and the strength,stiffness and mode of the car body meet the requirements of relevant standards.The research method used in this paper provides a certain reference value for the lightweight design of car body of rail vehicles in the future.