Sensitivity Analysis And Optimization Design Of Double EMU Body

With the development of modern technology, high-speed rail becomes a reality and faster. The high-speed train plays an important role in the technology of high-speed rail, but the problem is that the bulky body has limited its speed. So the lightweight of the High speed EMU body is a common trend in the design of passenger trains both at home and abroad. EMU body is the bearing structure of the passenger trains, and is one of the most important parts of the lightweight of vehicle structures.Taking the CRH3X double EMU body as the research object, I build a finite element model with Hypermesh software and analyze the strength, stiffness and modal’s sensitivity with the software of MSC. Nastran in the disertation. By analyzing the regular pattern based on the counting result and making weight as the minimum objective function, I design the lightweight body to meet the application requirements.The main contents include:Firstly, according to the Europe EN 12663 standard, I do the analysis and calculation of static strength of the CRH3X double EMU body in five working conditions. After checking, I find that the stress did not exceed the material’s allowable stress and the stiffness is greater than the criteria for evaluation.Secondly, to carry modal calculation of the CRH3X body. According to the bodywork modal assessment standards, empty body’s first order vertical bending frequency is not less than 17Hz and the readiness state of the body’s first order vertical bending frequency is more than 10 Hz. All above conform to the requirements.Thirdly, based on the CRH3X car body’s strength and stiffness and modal analysis, I calculate the thickness sensitivity of 41 design variables with differential method. These design variables include the sensitivity of the position body main stress, static displacement modal frequency of chassis, side wall, roof, under frame and curb girder.Finally, making the thickness of the roof plate as a design variable, the body structure’s minimum weight as the design objective, and the maximum stress of the vehicle body and the chassis maximum displacement of the bound as constraint, I complete the design of lightweight the body with method of feasible directions. The optimization results compared with previous results and verify the optimum result.