Stability of multi-body system under axial pulse load: An idealised model for collision stability of rail vehicles

AbstractThe longitudinal collision stability and critical instability criteria of rail vehicles is investigated herein, using an idealised model with multi-bodies connected by Shanley cells under axial pulse load. In this model, the car bodies of rail vehicles are idealized as rigid bodies, and their interactions are represented by Shanley cells, with two-dimensional motion being taken into account. Based on this model, the vertical and axial responses of the multi-body system before the occurrence of buckling are presented and discussed. Influences of key parameters (i.e., the shape, duration and intensity of the pulse load) on the collision stability of rail vehicles are revealed. An equivalent non-dimensional p_e-i_e diagram is drawn for arbitrary form of pulse loadings, by introducing two non-dimensional indices of effective impulse and effective peak load, to predict the instability of rail vehicles during the longitudinal collision process. Finally, the critical instability criteria of rail vehicles in longitudinal collision is presented. It is shown that the collision stability of rail vehicles is highly sensitive to loading parameters, and the distance between two flanges of Shanley cells significantly influences the critical instability boundary. The proposed theoretical model and the findings can be used to guide the optimal design of collision safety for rail vehicles.