汽车缓冲吸能式保险杠碰撞能量衰变特性研究

摘要

For energy-absorbing bumpers of automotive turning impact kinetic energy into multiple impact condition in an instant and realizing the purpose of multiple point synchronous or asynchronous absorption, the Hypermesh software was used to establish a finite element model for the energy absorbing bumper, and the ANSYS/Ls-Dyna solver was simulated for the crash analysis of maximum stress of the bumper and energy absorption characteristics of energy absorbing cushion de-vice and the characteristics of collision energy decay curves at different velocity as 10 km/h, 20 km/h, 30 km/h, 40 km/h and 50 km/h. The simulation results show that the energy-absorbing box of grooves and beams was suffered the greatest stress, and the beam stress was concentrated to the center distribution rule when the bumper was crashing, and when the stress con-centration increased a certain extent, the beam started bent in the center. With the increase of the impact energy, the energy absorption ratio of the energy absorbing device increased at first and then decreased. In the process of collision, the way of collision energy decay was the linear attenuation, along with the increase of the impact velocity, the slope of the collision en-ergy decay curve increased sharply.%针对汽车缓冲吸能式保险杠在瞬间将汽车撞击产生的动能转化成多向撞击状态，实现多点同步或异步衰减吸收的目的。基于Hypermesh软件建立汽车缓冲吸能式保险杠正面碰撞有限元模型，采用ANSYS/Ls-Dyna求解器对汽车正面撞击速度分别为10 km/h、20 km/h、30 km/h、40 km/h、50 km/h时保险杠的最大应力及缓冲吸能装置的吸能特性进行数值仿真，得到不同撞击速度下的碰撞能量衰变特性曲线，仿真结果表明：碰撞时吸能盒的凹槽处和横梁所受的应力最大，横梁所受的应力有向中心集中分布的规律，当其应力集中到某一程度时，横梁开始从中心处发生折弯；随着撞击动能的增加，吸能比呈先增大后减小的趋势；碰撞过程中，碰撞能量近似线性衰减，随着撞击速度的增加，碰撞能量衰减曲线的斜率急剧增大。