Modelling the singular rail and wheel surface defect for predicting railway ground vibration

Abstract

When undertaking a railway vibration assessment, the presence of singular defects on the rail and wheel surfaces significantly affects the ground vibration level. The objective of this paper is to analyse the most common of these defects found on urban lines and to derive the equivalent wheel/rail contact stiffness and wheel position relative to the rail. Special attention is paid to the modelling of wheel/rail interface, using a non-linear Hertzian contact. Theoretical analysis of the wheel/rail contact is performed in order to compute the Hertzian coefficient. To calculate ground vibration levels, a fully 3D numerical prediction model is developed, based on a two-step approach, combining a multibody analysis of the vehicle and a finite element analysis of the track and the surrounding ground. An application is proposed, based on the AM96 trainset, largely used in Brussels Region (Belgium). High-vibration levels are predicted in the presence of these defects. A selection of simulation results are presented in order to compare the defect type and to analyse the effect of the vehicle speed.