Optimization Design Of EMU Car Body Side Wall Structure Based On Stiffness Maximization

As an important component of Chinese transportation field,railway transportation accounts for more than half of the total national transportation volume.It is the core force of Chinese economic development and the main artery of the national economy.However,with the increasing demand for transportation,the requirements for railway transportation are getting higher and higher: larger volume,faster speed and higher safety.Therefore,it is of great necessity to find ways to improve the performance of trains.In order to match the increasing demand for rail transportation,the optimization design of car body structure has become a hot research topic.The side wall of the car body is the middle part connecting the roof,the end wall and the underframe.It is connected to the rest of the car body and is the main bearing part.This paper selects the side wall of a certain EMU car body as the main research object,and optimizes its stiffness and weight.(1)Considering the car body structure,through the model analysis and simplification,a reasonable finite element model of the car body is constructed.Based on the TB/T 3550.1 and other standards,the working conditions of the car body are loaded,and then the numerical simulation analysis is carried out to qualitatively analyze the weak links of the car body.The results show that although the car body has stress concentration in some positions and there are some weak positions,the car body meets the corresponding design requirements in terms of strength and stiffness.(2)In order to improve the efficiency of optimization analysis,the calculation model is appropriately simplified,and some important working conditions are calculated and optimized based on the half-car model.Firstly,the section selection of beam and column is carried out.Taking the side wall of the car body as the main research object,the section selection of the side wall beam and column is carried out according to different forms such as T-beam and I-steel.The overall stiffness of different structures under harsh working conditions is compared to determine the section shape.The results show that compared with the beam and column structure of other sections,the overall stiffness of the car body is higher when the side wall beam and column structure of the car body adopts the section of the B-beam.(3)The optimization model of car body side wall is constructed,and the size of car body side wall is optimized.The optimization work is divided into three parts.Firstly,the thickness of the beam-column structural plate of the side wall of the vehicle body is set as the design variable to maximize the stiffness of the vehicle body.The influence of different design variables on the stiffness of the side wall of the vehicle body under the weight constraint is analyzed and calculated.Secondly,considering the thickness of the side wall panel as the design variable,the weight of the car body is constrained,and the stiffness change of the car body under different grouping conditions is analyzed and calculated.Finally,on the basis of the above,considering the side wall beam column structure and the thickness of the side wall plate,the lightweight design of the car body is carried out under the condition of constant stiffness.