Intercity High-speed Train Section Optimization Design

ABSTRACT:Multiple goals are often utilized in practical engineering design optimization problems. In this paper, by taking CRH3X emu middle car as object, The strength, stiffness and free modal under empty and full load status are analyzed. Then based on the results of the analysis, several conditions are chosen by considering the performance indexes. Finally, this article explore the body section optimization method by means of approximation model. The article mainly completed the following several aspects:1. The establishment finite element model. The complex car body structure is simplified primarily based on a certain principle. Then car body finite element model is established based on HyperMesh;2. The car body structure performance evaluation index analysis. According to the relevant requirements of EN12663:2000, the strength of car body is analyzed under nine main working condition, and the free modal analysis is also processed under both empty and full load status. By analyzing the results, the body’s stress and displacement distribution are summarized, which provides reference for subsequent analysis;3. The establishment of car body optimal approximation model. On the basis of multidisciplinary parameter optimization platform-Isight, the sample is obtained by using the experimental design method firstly. By taking underframe section material thickness as the design factor and the vertical bending stiffness and torsional stiffness and modal as output response, approximate model of high precision is set up with using the response surface method based on sample results data;4. The section structure multi-objective optimization design. On the basis of the approximate model, the section structure is optimized by using the dominant genetic algorithm NSGA-Ⅱ and the optimal solution set of multi-objective Pareto is obtained. Three optimization solution are chosen and analyzed and it shows that comparing with the original design scheme, the bending rigidity is still improved when the mass drops in part of solution, which achieve the objectives of the optimization design;5. The shape of the car body section optimization. The rib angle of underframe section is changed by using Sculptor. It shows that by using Isight which integrated with Sculptor and Ansys to calculate, the method which combines grid deformation technology and parametric optimization method is feasible when takes the car body optimization. The method can obtain a better design scheme, which has a guiding significance for later design and layout of the rib in the underframe.To sum up, a variety of alternatives are provided for the design of the high-speed train car body section through the study of this article, which has some reference value.