| With the rapid development of high-speed railway,the train running speed is constantly improving,and the structural safety problems of the car body become more and more important.The stainless steel car body with the advantages of light weight,high strength and corrosion resistance is gradually applied to the design of the car body of subway vehicles,so it is very important to study the strength and fatigue life of stainless steel car body.Based on the B type stainless steel body of subway developed by a factory,the main research contents are as follows:(1)The model of the research and analysis of the subway car body is established,and the model of the car body structure is simulated by the shell unit provided by the manufacturer,including the roof,side wall,end wall and underframe,which lays the foundation for the analysis of the static strength of the vehicle body from the angle of the whole vehicle.The modeling software can not completely restore the actual structure of the subway car body,which is to change part of the structure of the subway car body.There are many solder joints in the actual structure of the subway car body,and the functions and types of these welding points are different.(2)After determining the working conditions and boundary conditions,the static strength of the vehicle body is analyzed,each working condition is loaded into the model by the pre-processing software Hyper Mesh,and then the finite element calculation is carried out by using the Ansys software to obtain the von-mises cloud diagram,observe the position where the maximum stress occurs,and compare it with the allowable stress of the position,calculate the load bearing capacity of the whole vehicle and verify whether the model meets the prescribed requirements according to the results.Based on the Optistruct software,the first 10 modes of the car body are calculated,and the results are checked to verify whether the mode of the subway car body meets the requirements.(3)Through Hyper Mesh software to add three specific fatigue conditions to the car body model,the Ansys software is used to calculate,and six to seven stress points with the first main stress are selected under each working condition,and the fatigue life evaluation is based on the method of calculating the cumulative damage ratio in the BS7608-1993 standard.(4)On the basis of the analysis results of static strength,displacement and fatigue life evaluation,the stress points and car body structure with concentrated stress and larger displacement are observed,and the local size optimization of car body structure is carried out by using Optistruct software,and then the thickness parameters of part structure of car body are modified by Hyper Mesh software to achieve the purpose of lightweight.and the optimized model is imported into Ansys software again for calculation and comparison.And then Optistruct the local structure of the car body by the software topology optimization,topology optimization is an essential optimization method.Through the above research,the following conclusions are drawn :(1)The modal vibration frequency of the car body meets the requirements,and the static strength and stiffness meet the standard requirements.(2)The cumulative damage of 20 fatigue assessment points of the car body is less than 1,and the fatigue strength meets the requirements of use and is safe.(3)The plate thickness of the stainless steel car body is determined and the light weight is realized.(4)The results of local structure topology optimization show that the stress-exceeding stress-constrained grids account for 0.6% of the total grids and are within acceptable range. |
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