现代有轨电车碰撞脱轨影响因素

运用多刚体动力学理论对有轨电车与汽车在平交道口的碰撞进行仿真分析.研究结果表明有轨电车在平交道口受到汽车以20km·h-1的速度侧面撞击时,有轨电车的最大脱轨系数达到1.63,超过标准GB5599—1985中规定的第一限度(1.2),具有较大的脱轨风险.此外,撞击后有轨电车的动态响应以及脱轨风险在很大程度上受到碰撞边界条件的影响.当汽车撞击有轨电车前后两端头车时,被撞击车辆承受的横向碰撞力仅能通过一侧的车间铰接结构向其他车辆进行传递,导致有轨电车脱轨系数较高.随着汽车质量和撞击速度的增加,碰撞力显著增加,有轨电车的脱轨系数也逐渐加大.当有轨电车撞击点与车体质心间距的逐渐加大,被撞击车辆除了承受剧烈的横向冲击还产生一定的摇头运动,加剧有轨电车碰撞后脱轨的风险.轮轨摩擦系数由于雨雪等天气因素降低时,一方面车辆所需要的制动距离明显增加,更容易造成碰撞事故的发生;另一方面钢轨对于车轮运动的抑制作用减弱,加大了有轨电车脱轨的风险.

Effect factors on the City tram Derailment during a collision

The collision simulation between a city tram and an automobile at the level crossing is carried out based on the multi-body dynamics. The research results indicate that when the city tram is impacted laterally by an automobile with a speed of 20 km?h-1, the maximum derailment coefficient of the city tram is 1.63, exceeding the limit (1.2) defined in the standard GB5599-1985. That means the collided city tram has a high risk to derail. Besides that, the dynamic response and the derailment risk of the collided city tram are affected seriously by the collision boundary conditions. When the first or the last vehicle of the city tram is collided by the automobile, the lateral impact load can be transmitted to the adjacent vehicle by only one side, which results in a high derailment coefficient. With the increased impact mass and speed of the automobile, the impact force is obviously increased. As a result, the derailment coefficient of the city tram is also gradually increased. As the distance between the impact point and the mass center of the car body increases, the collided city tram is endured not only the lateral impact force but also the yam moment. Due to this reason, the collided city tram has a high risk of derailment. Besides that, when the friction coefficient decreases due to bad weather, the braking distance of city tram and automobile increases, so that the collision accident is more likely to occur. On the other hand, the reduced friction coefficient decreases the wheel-rail forces against the lateral motion of wheel sets. As a result, the collided city tram is more likely to derail.