| In this thesis, the CRH3 EC01 EMU is our main study target. We determined the direction and goals on Structural Optimization by the structural strength calculation and checking on fifteen kinds of load cases. Then we do the structural optimization study mainly on the body weight and the structural strength based on ISIGHT Optimal Design of platforms.1. According to the European《EN12663》Standard, strength for body shell 15 load cases is calculated, and Von Mises stresses and displacement distribution are obtained, then strength is verified. Characteristics of body shell's stresses distribution and structure designing are summarized. We find the six kinds of load cases of excessive static strength and the maximize VON Mises stresses area is in the coupler region.2. By the analysis of body shell's structural strength, characteristics of body shell's stresses distribution and structure designing are summarized and the direction and goals on Structural Optimization are determined. The thickness of profile in the coupler region is the design variable and the value of maximize Von Mises stress is the objective, we study the optimal design of structural stress based on discrete design variable by two programs and obtained two good result to make the structural stress meet the standard.3. We studies on the minimum weight of the vehicle body based on the optimization result step forward. By changing the profile thickness of chassis, side wall, roof and so on, we obtained the minimum weight of vehicle body on meeting the standard of strength and stiffness. Because of the EC01 EMU is the first one of the CRH3, so we must consider the security seriously.4. Based on the integration function and optimization function of platform ISIGHT, we developed three different optimization schemes with DOE, approximate models and different Algorithm such as Hooke-Jeeves Direct Search Method and Multi-island Genetic Algorithm. Then we obtain some good result and compare the efficiency of different schemes.
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