基于局部搜索和整体优化的客车杆件截面参数正向设计

Top-down design method based on local search and global optimization for cross-sectional size of bus body

首先建立了局部一维搜索方法,以客车车身线框模型与型钢截面库为基础,通过截面库优化排序、杆件局部模型一维搜索以及局部-整体迭代等优化步骤,得出一个满足多工况强度要求的车身结构杆件截面尺寸下限。然后通过灵敏度分析选择关键杆件,利用多目标遗传算法NSGA-II对选定杆件的截面尺寸在截面库的范围内进行优化,以提高整体刚度及模态性能。最后在某承载式客车车身杆件截面优化设计中,将该方法的优化结果作为设计输入,结果表明,车身结构的最终方案具有明显的轻量化效果。

In this paper, first, the lightest structure under the strength condition was obtained via the implementation of strength optimization based on the wire-frame model of body structure and the sectional library. Sequencing optimization of the sectional library, local line search and local-global iterative process were contained in the strength optimization. Second, sensitivity analysis was carried out to select design variables, which are more sensitive to the stiffness and modal frequency of the body structure. Finally, the selected variables were optimized within the limits of sectional library to improve the performance of the body stiffness and modal frequency using the multi-objective genetic algorithm NSGA-II. This approach was implemented into the design process of an integral bus body. The results indicate that the proposed sectional optimization method is efficient and conducive to lightweighting of bus bodies.