基于梯度的等效静载荷法的汽车正面碰撞关键结构优化设计

Design Optimization of Key Structures in Frontal Crash Based on ESLMG

针对在已有车型的继承式开发中,由于结构尺寸、总布置等因素限制,无法快速准确地进行结构非线性优化设计的问题,提出了一种基于梯度的等效静载荷法与G_1-G_2设计规则以及载荷传递路径相结合的正面碰撞关键结构优化设计流程:收集对标车型数据,根据G_1-G_2设计规则,确定满足乘员损伤的最优目标加速度等效双阶梯形波;建立载荷数据库,得到一类车型的碰撞载荷路径百分比分布图;提取基础车型正面碰撞关键部件,以目标波形为指导对其进行必要的截面尺寸优化,并运用ESLMG对其进行厚度优化;将优化后的关键部件放入整车模型中,验证其加速度曲线是否达到目标值。结果表明,优化后的结构特性基本达到目标要求,整车碰撞性能得以改善。

In inheritance development processes of existing vehicle models, it was difficult to op- timize and redesign the structures efficiently and accurately because of the limitations of structure si- zes and general arrangements. A procedure which contained with G1 -G2 design regulation, crash load path and an ESLMG was proposed to overcome the disadvantages to improve the performance of key structures in frontal crash. First, the equivalent double step target curve was defined, which was satisfied for the requirements of passenger injury according to G1 -G2 regulation and crash loads database was built by collecting and analyzing competing models. Then, frontal crash key structures of original model were determined as optimization objects and the thicknesses of them were optimized using ES- LMG after optimizing their shapes. Finally, the optimized structures were input into full vehicle model to verify if its acceleration curve had achieved the optimization target or not. The validity of this procedure was proved with the calculation results of numerical examples.