| Abstract: | This study investigated the wheel-lift and roll-over derailment mechanisms caused by train collisions using a precise virtual testing model (VTM) of a Korean high-speed train. The VTM was a complex, nonlinear finite element model composed of the shell, beam, solid, spring, and surface contact elements for the car body, bogies, suspensions, and wheel–rail interfaces. The VTM was validated by checking the errors in the total energy and the dynamic responses of the spring elements. To achieve a quick, dynamic relaxation of the dead weight of the VTM before the collision analysis, the artificial damping method and the artificial force method were introduced and numerically evaluated. The surface-to-surface contact model from commercial software, Ls-Dyna, was applied to the VTM in order to simulate the derailment mechanisms caused by collision accidents. The numerical analyses of the VTM colliding with a large deformable obstacle or a rigid wall revealed for the first time that a mixed slip/roll-over-type derailment mechanism generally occurs. Furthermore, the simulation results were consistent with the results from a simplified theoretical derailment model of a wheel set. |
