Effect factors on the City tram Derailment during a collision

Abstract:

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.