Characterizing wheel flat impact noise with an efficient time domain model

Abstract

To investigate railway impact noise caused by discrete rail or wheel irregularities, such as wheel flats, rail joints, switches and crossings, a time-domain wheel/rail interaction model is needed. However, time-domain models are normally time consuming to solve and this makes it difficult to carry out parametric studies and gain insight into physical behaviour. A simple mass-spring equivalent track model is developed here to gain insight into the impact vibration induced by a wheel flat irregularity. With the track system simplified to only three degrees-of-freedom, the calculation times of the wheel/rail interaction simulation are reduced by a factor of 10 compared to a corresponding finite element track model. Using this very efficient time-domain wheel/rail interaction model, the characteristics of impact noise in the audio frequency range due to a wheel flat are studied.