高速公路防撞垫计算模型动力响应的研究

Research on the dynamic response of highway crash cushion computational model

为减少防撞垫传统设计过程中对实车碰撞试验和三维数值仿真分析的依赖,将防撞垫简化为多个串联的吸能元件,并将车辆和吸能元件均简化为弹簧-质量单元。采用多自由度弹簧-质量系统模拟车辆正面碰撞防撞垫的过程,最终得到相应的计算模型。以包含两个吸能元件的防撞垫为研究对象,使用显式动力学软件LS-DYNA对计算模型进行数值分析,并验证了计算模型的准确性。在满足国内乘员安全规范的前提下,对防撞垫计算模型的屈服荷载Py、屈服前刚度kd、屈服后刚度kt、形状系数c进行了研究,完成了1.3t的车辆以60km/h速度正面撞击防撞垫工况下,防撞垫计算模型的动力响应分析。

Traditional crash cushion design usually depends on the real vehicle crash tests or the three-dimensional numerical simulation analysis, which are commercially or computationally expensive. A new crash cushion computational model is proposed in this paper. Specifically, it treats the crash cushion as a series of energy absorbing elements(EAEs), these EAEs and vehicles are simplified as a bunch of spring-mass elements. So the frontal collision process of a vehicle and crash cushion boils down to a spring-mass system with multiple degrees-of-freedoms. The computational model is implemented in the LS-DYNA software and applied to a crash cushion example composing two EAEs. The key factors in the model, such as yield load Py, initial stiffness kd, post-yield stiffness kt and shape factor c, are analyzed under the national occupant safety standards. Finally, the dynamic response analysis of the model is performed on a frontal collision experiment of a vehicle and the crash cushion, where the vehicle has weight of 1.3 t and speed of 60 km/h.