Dynamic response of sleepers in a track with uneven rail irregularities using a 3D vehicle–track model with sleeper beams

Abstract

Employing a 3D model of the vehicle–track interaction, dynamic responses of sleepers in railway tracks are determined due to the effect of uneven irregularities (cross-levels) in left/right rails. An integrated mathematical model of the vehicle–track system is used to calculate the dynamic behavior of sleepers in the railway track. The general methodology of the dynamic analysis is presented by extracting the mathematical equations and by introducing the coupling process in the wheel–rail interface. Besides the vertical (bounce) and pitch motions, roll degrees of freedom of the components are taken into account. Except rails and sleepers, other components of the vehicle–track system are simulated with the rigid-body elements, linked to each other within the resilient elements (springs and dashpots). The rails and sleepers are modeled with the beam elements, making the model more detailed in the track subsystem. A numerical integration algorithm based on Newmark’s method is developed, capable of solving the dynamic interaction of the entire system in time domain. Applying various irregularity profiles from the field measurement data as the source of excitation, the dynamic response of sleepers in track structure is treated in the longitudinal and traverse directions. Dynamic displacements under sleepers are compared with the analytical solution of the beam on elastic foundation (static response) to highlight the dynamic amplifications. The results of analysis show that the profile unevenness in left/right rails plays an important role in dynamic stability of the sleepers in railway track, particularly when the severity of the profile unevenness was increased.