中文摘要：

建立了某大型客车车身骨架FE模型，获取了自由模态参数以及静态弯曲和扭转工况下的刚度和强度特性。基于分析结果，对车身骨架结构形式进行了改进。利用优化设计方法，建立了以客车薄壁梁厚度为设计变量，车身总体积和表征车身刚度的状态量为响应的优化模型。通过对影响车身轻量化和力学性能指标构件的灵敏度分析，筛选了设计变量，重新建立了以车身骨架总体积最小为目标的优化模型，得到了轻量化效果明显的优化方案。最后对轻量化模型进行典型工况分析，与初始模型进行了对比，验证了优化方案的可行性。

英文摘要：

The FE model of coach skeleton was developed. The normal modal parameter, indicators for stiffness and strength properties under static bending and torsion cases are calculated. Based on the analysis results, the structure Configuration of the skeleton was modified accordingly. Optimization model for lightweight design was for- mulated. The thicknesses of skeleton components are selected as design variables, and the volume of coach skeleton together with the indicators for the stiffness of the skeleton are set as responses. A sensitivity analysis is conducted to select the design variables which affect the structural performance most, followed by an updated optimization model with these selected design variables. Finally, saving. The feasibility of the optimization scheme is alightweight scheme is proposed to reach a significant weight- verified by the comparison with the original model.