Optimization Design Of The Railway Trucks Body And Fatigue Life Forecast Of Seam Weld

The technology of railway wagon is high developing to the heavy load and high velocity for improving transport efficiency and save cost, the lightweight of railway vagon is a precondition. In this paper, we take C80 railway wagon body as an analysis object, the initial static analysis of this wagon shows that the value and distribution of stress is not ideal namely the stress of some parts is very low, and that stress of others parts almost reached the allowable stress. It shows that the material of some parts does not fully play its role, and the intensity of some parts is lower, optimization design can effectively change the status of the irrational material distribution and is a main measure of lightweight design for the wagon body.In this paper, the finite element model of C80 wagon body is created, and the strength and stiffness of wagon body under the multi-load is computed basing on Hypermesh/Optistruct Software; the thicknesss of plates for wagon body are taken as design variables, the strength and stiffness of wagon body are used as restrictions, the wagon body weight is taken as the objective for minimum, a optimization design model is formulated, the feasible direction method is used to optimized the design variables, then the optimization designs considering multi-load strength and stiffness restrictions are achieved for reducing the wagon weight and improving the stress distribution.After optimization, the weld fatigue life and buckling stability of wagon body are evaluated. The weld fatigue life is evaluated using structural stress method which is based on the mesh-insensitive, the stability analysis mainly considered buckling stability under compression load. The main research contents and conclusion are follows:1. The geometric model and finite element model of C80 wagon body are established, the static strength and stiffness are calculated;2. In order to determine whether there is enough design space for optimization, the buckling stability of the wagon body was analysed and the main weld fatigue life was forecasted for C80 wagon body;3. The size optimization model and topology optimization model are formulated, then size and topology optimization designs are carried out for reducing the wagon body weight;4. The buckling stability of the optimized wagon body are evaluated, the optimized results are corrected basing on stability conditions, then static strength,stiffness and buckling stability are all met;5. The main weld fatigue life of the corrected wagon body according to the buckling stability are evaluated. In this paper, the structure optimization design of wagon body has been completed successfully basing on Hypermesh/Optistruct software and a mass reduction of a 13.83%for wagon body is achieved, at the same time, static strength and stiffness, buckling stability and weld fatigue strength meet the requirements, the lightweight of wagon body is achieved and a new method for lightweight design of railway wagon body is brought forward. Basing on this study, the integrated size, topology and shape and the multi-disciplinary optimization design including more load can be carried out to improve the design level of railway wagon.