基于耐撞性能的保险杠轻量化研究

Research on lightweight of bumpers based on crashworthiness

汽车保险杠结构的耐撞性与轻量化之间的矛盾是设计保险杠结构主要考虑的问题。针对某型轿车保险杠系统,通过对原钢制保险杠进行有限元仿真分析,发现该钢制保险杠的性能达不到该车型低速碰撞的要求。因此,为了实现耐撞性和轻量化的目标,将6061铝合金应用到该保险杠系统中,并将碰撞力和质量作为约束条件建立最大吸能的优化模型,以保险杠外侧板厚度、中间板厚度、内侧板厚度以及吸能盒上下板壁厚作为设计变量进行最优拉丁超立方设计,利用LS-DYNA有限元分析软件得到不同变量情况下的信息,采用二阶响应面法拟合出近似函数,结合响应面模型和具有模拟退火过程的ASA算法对5个板件厚度进行优化,在整车碰撞中比较优化后的保险杠和原钢制保险杠,结果证明该设计方案是切实可行的。

The contradiction between the crashworthiness and lightweight of automobile bumper structure is the main problem in the design of bumper structure.For a certain type of car bumper system,the finite element analysis of the original steel bumper was carried out,and it was found that the performance of the steel bumper could not meet the requirements of low-speed collision.Therefore,to achieve the goal of crashworthiness and lightweight,the 6061 aluminum alloy was applied to the bumper system and the optimal model of the maximum energy absorption was established with collision force and mass as the constraints.The optimal Latin hypercube design was carried out with the thickness of the outer panel of the bumper,the thickness of the middle panel,the thickness of the inner panel and the wall thickness of the upper and lower panels of the energy absorption box as the design variables.The LS-DYNA finite element analysis software was used to obtain the information under different variables,the second order response surface method was used to fit the approximate function,and the response surface model and the adaptive simulated annealing(ASA)algorithm were combined to optimize the thickness of five panels.The performance of the optimized bumper and the original steel bumper were compared in the vehicle collision,and the results show that the optimized design scheme is feasible.