Abstract: The lightweight automobile body is a key subject in the design and development. Based on the existing steel and aluminum hybrid body platform of electric vehicles, under the premise of keeping the structure of the lower body unchanged, the original steel material of the upper body is replaced by aluminum material by equivalent stiffness and sensitivity analysis method, and the performance of the body is systematically compared. The results show that the weight of allaluminum body structure is reduced by 20% and the lightweight coefficient is increased by 18% compared with that of upper steel and under aluminum body structure on the premise that the key performance of the body bending and torsional stiffness, bending and torsional model, collision performance is basically the same. It provides important theoretical support and guiding significance for the structural design and application of aluminum alloy materials in the future.

Key words: the same platform architecture; steel-aluminum hybrid structure; all-aluminum structure;lightweigh

摘要： 车身轻量化是车身设计和开发的重点课题。文章基于现有电动车钢铝混合车身平台， 在保持车身下车体架构不变的前提下，将上车体原来的钢制材料通过等效刚度和灵敏度分析 方法替换成铝制材料，并对车身性能进行了系统性的对比研究。研究结果表明，在保证车身 关键性能（弯扭刚度、弯扭模特、碰撞性能）基本相当的前提下，全铝车身结构相比上钢下 铝车身结构，重量降低 20%，轻量化系数提高 18%。为后续车身铝合金材料的结构设计和大 量应用提供了重要的理论研究支撑和指导意义。

关键词: 同平台架构；钢铝混合结构；全铝结构；轻量化