常用波形梁护栏端头碰撞分析

车辆碰撞圆头式和地锚式端头时会发生恶性事故,故建立车辆碰撞端头的有限元模型,从侧面和正面碰撞两个角度对端头进行安全评价,分析事故形态和原因,以为新型端头的开发研究提供建议。研究结果表明:正面碰撞圆头式端头时,会发生波形梁板刺穿车体的事故;正面碰撞地锚式端头时,会发生翻车甚至翻滚的事故;侧面碰撞圆头式端头时,会发生车辆冲开护栏的事故;侧面碰撞地锚式端头时,会发生车辆翻越护栏的事故。通过对事故形态的分析,得出圆头式端头面积小且不能移动是波形梁板插入车体的主要原因,立柱不可倒伏是车辆加速度超标的主要原因,端头锚固力不足是车辆冲开护栏的主要原因,车辆爬升地锚式端头是翻车的主要原因。建议开发的新型波形梁护栏端头,能够沿波形梁板移动,与端头连接的立柱可倒伏,同时新型端头能够为标准段提供足够的约束力。以此为基础开发的新型波形梁护栏端头已应用于实际工程。

Analysis on Impact of Traditional W-beam Guardrail Terminals

Serious accidents would happen if car impacted bullet-headed or anchored W-beam guardrail terminal. Finite element analysis models were set up to simulate impact between car and the two kinds of guardrail terminals in frontal and side direction. Through the simulation results, the safety performances of the terminals were evaluated, the accident configuration and reason were made and suggestions were brought out to develop a new type W-beam guardrail terminal. The analysis indicates that W-beam terminal will penetrate into the car body when car impacts bullet-headed guardrail terminal in frontal direction, car will turn over or roll when car impacts anchored guardrail terminal in frontal direction, W-beam will be broken when car impacts bul- let-headed guardrail terminal in side direction and car will over fly barriers when car impacts anchored guardrail terminal. The reason of the terminal penetrates into the car body is that the bullet-headed terminal is unmovable and its area of terminal is small. The reason about acceleration of car is greater than the regulation of criterion is that the anchor connected to terminal is not droppable. The weaken anchor force of terminal is the reason of car cracks up the barrier. The reason of car＇s turning over is the car climbs the anchored terminal along its slope. Suggestions on new type W-beam guardrail terminal development, such as the terminals is moveable in W-beam direction, the anchor connected to terminal is droppable and the terminal has enough anchor force for standard barrier, are proposed based on the analysis of accident performance simulation. A new type W-beam guardrail terminal has been developed and applied in practice based on the analysis.