Rail surface spot irregularity effects in vehicle-track interaction simulations of train-track-bridge interaction

Abstract

The presence of rail surface damage leads to increased vibrations on railway bridges as wheels cross the localized irregularities. These short wavelength irregularities appear frequently on the top of rail in railway tracks and, along with the increased axle loading, fatigue failure accelerates, and ultimately, serviceability decreases. Compromised bridge safety and reliability is countered by an increase in inspections as bridge structures continue to age and deteriorate. In recent years, the effects of rail surface spot irregularities on the condition of railway bridges have attracted the attention of the industry and the research community. This study has two objectives. Firstly, it introduces the methodology, algorithms, and models for Vehicle Track Interaction (VTI) simulations developed to study the effects of Rail Surface Spot Irregularities (RSSI) on system response. The proposed VTI simulator solves the wheel-rail interaction problem in a Staggered Time Marching (STM) form. Long- and short-wave surface irregularities are accounted for. A multi-point wheel-rail contact algorithm is developed and implemented for properly capturing the wheel contact points in view of the relative size of the wheel and the rail surface irregularities. The proposed method is verified analytically. Subsequently, this paper investigates and quantifies the effects of the shape and location of RSSI on the vibrations of the bridge structure and the train for different train speeds. It is shown that RSSI affects wheel-rail interactions forces significantly and the induced vibrations substantially stimulate bridge velocity and acceleration. The effects are more pronounced for specific RSSI locations and train speeds.