Analyses of dynamic behavior of track transition with finite elements

New types of vehicle and track elements are presented, by means of the finite element method, to establish a model for dynamic analysis of vehicle-track-subgrade coupling systems. The associated stiffness matrix, mass matrix and damping matrix for these two types of elements are deduced. Computational software is coded with Matlab. As an application example, the dynamic behavior of track transition is investigated by the vehicle and the track elements. The influencing factors for the simulation include train speed, subgrade stiffness, and irregularity angles of track transition as well as the transition pattern. The computational results show that 1) Abrupt changes of the subgrade stiffness influence the vertical acceleration of the rail and the wheel/rail contact force, and this influence increases with increases in train speed, 2) Both the irregularity angles of the track transition and the abrupt changes of the subgrade stiffness have significant effects on rail vertical acceleration and the wheel/rail contact force, with the peak value in this situation being greater than that generated by irregularity angles of the track transition or the abrupt changes of the subgrade stiffness, 3) Train speed, abrupt changes of the subgrade stiffness, and track transition irregularity angles have a minor influence on the vertical acceleration of the vehicle due to the excellent behavior of vibration isolation resulting from the primary and the secondary suspension systems of the vehicle, 4) Transition pattern for irregularity of track transition has a significant influence on the vehicle acceleration and the wheel/rail contact force, and the cosine transition is a much better indicator than the linear transition, and 5) Influences of the directions the train is moving on the dynamic behavior of the vehicle and the track are relatively insignificant.