Dynamic responses of railway sleepers to coupling vertical and lateral forces

It is unquestionable that railway infrastructure is naturally a complex system. Its behaviours, geometry and alignment, wheel-rail forces and operational parameters such as tractive efforts are often found to be nonlinear and asymmetrical. Not only does the complex train-track interaction generate vertical impact loading, but the curving behavior of the train body also induce dynamic lateral force acting on the rail. This paper presents a numerical simulation of a standard-gauge concrete sleepers, taking into account the tensionless nature of ballast support. The finite element model was calibrated using static and dynamic responses using experimental data. Previous extensive studies revealed that the two-dimensional Timoshenko beam model is the most suitable option for modeling concrete sleepers under vertical and lateral loads. In this investigation, the finite element model of Timoshenko-like concrete sleeper has been developed and calibrated against the numerical and experimental modal parameters. The influences coupling loads on the dynamic behaviours of concrete sleepers are investigated. In addition, it is the first to demonstrate the effects of material damping on the dynamic spectra of railway sleepers. The dynamic properties of sleepers are critical to dynamic serviceability of both track systems and sleepers themselves. The insight from this study will improve the material design criteria in order to improve train-turnout interaction and ride comfort.