A lightweight numerical model of railway track to predict mechanical stress state in the rail
Résumé
A new approach is conducted within SNCF Réseau to redefine and improve the actual procedure behind rolling stocks admission. A perspective to update computation rules for traffic conditions is to consider track fatigue issues. In this sense, the study aims to provide a better knowledge of stress state induced by moving vehicles in rails through a lightweight numerical model of the track. Specifically, the track model consists of a two-layer discrete support model in which the rail is considered as a beam and sleepers are punctual masses. The rail pads and ballast layer are modelled as spring/damper couples. Considering the track’s vertical response, the study intends to quantify the impact of the vehicle’s dynamic overload on the track response and verify the possibility of these overloads to excite track vibration modes. A first study considering constant moving loads already shows negligible effect of track inertia forces due to high track stiffness and damping. This justifies the prediction of mechanical stress state in the rail for fatigue issues through a static model of the track and a simplified dynamic
model for the vehicle.