车辆撞击中央分隔带开口活动护栏仿真分析及安全性能评估

Simulation Analysis on Median Movable Opening Barrier under Vehicle Impact and Safety Assessment

为了研究不同类型车辆撞击下中央分隔带开口活动护栏防护性能,保证撞击后车辆以及乘客的安全,结合护栏防护等级和高速公路常见的车辆类型,基于显示动力有限元软件LS-DYNA分别建立了小型客车、大型客车和大型货车撞击护栏的精细化数值仿真模型。护栏结构采用梁单元和壳单元模拟,车辆结构采用壳单元模拟,该模拟方法可以有效反映高速碰撞下车辆和护栏的非线性动力响应行为。通过分析3种车辆撞击护栏不同位置时护栏的最大变形,研究了结构的耗能能力和抗撞性能,探讨了撞击过程中车辆的运动轨迹、速度和加速度的变化规律,实现了车辆撞击下中央分隔带开口活动护栏安全性能的综合评估。结果表明:小型客车﹑大型客车和大型货车撞击护栏后均能返回正常的行驶路径,表明护栏具有较好的导向能力;波形梁板在车辆撞击下产生较大结构变形,具有较好耗能能力;BFI型防阻块有效降低了车辆的撞击动能,具有良好的抑制车辆侧翻的能力;小型客车撞击后乘员碰撞速度和加速度的横向与纵向分量均满足护栏缓冲功能要求。建立的中央分隔带开口活动护栏具有较好的阻挡功能﹑导向功能和缓冲功能,护栏安全性能满足SB防护等级要求。分析结果可为护栏结构设计和性能优化提供理论参考依据。

To investigate the protection performance of median movable opening barrier impacted by different vehicle types, and ensure the safety of vehicles and passengers after impact, combining with the protection level of barrier and the common types of vehicles on expressways, the refined numerical simulation models of small passenger car, large passenger car and large truck impacting barrier are established by using the explicit dynamic FE software LS-DYNA. The barrier structure is simulated by beam element and shell element, and the vehicle structures adopt shell element. This simulation method can effectively reflect the nonlinear dynamic response behavior of vehicle and barrier under high-speed impact. Through analyzing the maximum deformations of barriers when 3 types of vehicle impacting different positions of the barrier, the energy dissipation capacity and impact resistance of the structures are investigated, the changes of trajectory, velocity and acceleration of the vehicles during impact are discussed, and the comprehensive evaluation of safety performance of median movable opening barrier under vehicle impact is performed. The result shows that(1) the 3 types of vehicle can all return to the normal driving path after impact the barrier, indicating that the barrier has good guiding ability;(2) the corrugated plate experienced large deformation after vehicle impact and has better energy consumption capacity;(3) the BFI-type obstruction block can reduce the impact kinetic energy of the vehicles, and has good capacity in vehicle rollover inhibition;(4) the lateral and longitudinal velocities and accelerations of passenger under passenger car impact meet the buffering requirement of the barrier. The proposed median movable opening barrier has good functions of blocking, guiding function and buffering, and the barrier safety performance meets the requirements of SB protection level. The analysis result can provide a theoretical basis for the structural design and performance optimization of barriers.