Analysis of the Periodic Orbit in a Discretely Supported Railway Track Under a Moving Load

This paper studies the periodic orbit that appears in the deformation of a railway track on ballast with discrete supports due to a moving load.The track modeling methodology is based on the finite element method.A convergence analysis is performed to determine the number of elements per span needed to obtain accurate and reliable results without unnecessarily increasing computational costs.A sensitivity analysis of the main track parameters is also performed to study their influence on the periodic orbit.Different orbits are obtained depending on the velocity on the moving load and the value of the load itself when the velocity is constant, respectively.Additionally, the influence of the stiffness of the railpads and the ballast, respectivelly, on the maximum deflection of the orbit is analyzed.The result obtained is that the shape of the orbit depends little on the speeds considered, but the deflection increases with speed.As logic indicates, the deflection in the orbit increases as the load increases for a constant speed.Regarding the influence of the stiffness of the railpads and the ballast, the conclusion is that it is greater for low stiffness and decreases as the stiffness increases.