Lightweight And Structural Optimization Design For Middle Body Side Wall Of CEMU

With the problem of resource shortage increasingly prominent, the design of lightweight get more and more attention by designers, in which it is a persistent topic that the trade-off between the performance improving and material using. In this article, structural strength, stiffness and modal of CEMU vehicle body were analyzed for verification, regarding the body side wall as the research object. To acquire the lightest body quality, it employs single objective and multi-objective optimization to explore more than two kinds of optimization conditions, and conducts the shape optimization design of side wall reinforcement plate angle on the basis of size optimization results. The main contents of this article include:(1) Considering the bodyshell complex, it establishes the finite element model of the middle vehicle body after simplified appropriately and reasonably.(2) According to EN12663:2000, it analyzes strength, stiffness and modal in 11 kinds of main conditions to understand the influence of car body related performance.(3) Using simcode in ISIGHT integrated ANSYS, it accomplishes the single objective and multi-objective optimization with the thickness of side wall as the design variables, the lightest body quality as the objective. Firstly, it uses experimental design method to sample selection of design variables and obtains the sensitivity of design variables on corresponding performance. Then it uses Multi-Island Genetic Algorithm based on approximate model and gradient optimization algorithm NLPQL optimization strategy to complete single objective optimization of car body quality, and Multi-Island Genetic Algorithm to complete multi-objective optimization. Multi-objective optimization result is suitable for the operation of the body relatively via the two kinds of optimization results comparing considering the comprehensive performance.(4) Based on multi-objective, grid deformation technology is used to establish control domain to realize the control to side wall reinforcement plate. A universal component Simcode integrated HyperMesh and ANSYS through the ISIGHT, regarding stiffness and first order vertical bending vibration frequency of the side wall as objective function, finally it obtains the reasonable layout side reinforcement plate angle and the optimized bending stiffness, torsional stiffness and first-order vertical bending vibration frequency improve. The research of this article provides certain reference value for structure analysis of high speed vehicle and the optimization design of large structure, and also makes certain foundation for further studies of railway vehicle’s optimization design.