基于行人头部保护的汽车发动机罩系统优化设计

Optimization Design of Vehicle Hood System Based on Pedestrian Head Protection

摘要: 为满足某汽车发动机罩系统轻量化、刚度模态特性、行人头部保护的综合性能需求，使用HyperWorks软件对发动机罩系统进行了基于性能仿真驱动的优化设计。首先对初始发动机罩内板进行刚度模态的静态性能分析，对整车模型进行了行人头部碰撞仿真实验，计算出八个关键试验点的伤害值；其次在四种不同工况下对发动机罩内板进行了单目标拓扑优化，在此基础上利用折衷规划法对内板进行了多目标拓扑优化，并对结构改进后的模型进行了安全性能和静态性能的分析检验；最后运用全局响应面法对发动机罩系统进行了多目标多学科联合匹配优化，对优化结果进行了性能仿真验证。最终优化结果表明：改进后的内板结构和发动机罩系统材料厚度匹配方案，使刚度得到增加，一阶频率大于共振频率，发动机罩系统质量减少，关键试验点伤害值得到降低，实现了轻量化的同时提升了静态、安全性能。

Abstract: In order to meet the comprehensive performance requirements of lightweight, stiffness modal characteristics and pedestrian head protection, HyperWorks software is used to optimize the hood system based on performance simulation. Firstly, the static performance of the initial engine hood inner plate stiffness mode is analyzed, the pedestrian head collision simulation experiment is car-ried out on the whole model, and the damage values of eight key test points are calculated. Secondly, the single objective topology optimization of the inner plate of the hood is carried out under four different working conditions. On this basis, the compromise programming method is used to carry out multi-objective topology optimization of the inner plate, and the safety and static performance of the improved structure model is analyzed and tested. Finally, the global response surface method is used to optimize the engine hood system, and the results are verified by simulation. The final op-timization results show that the improved inner plate structure and the material thickness match-ing scheme of the hood system can increase the stiffness, the first-order frequency is greater than the resonance frequency, the hood system mass is reduced, the key test point hurt value is reduced, and the static and safety performance is improved while lightweight is realized.