Dynamics of railway track subjected to distributed and local out-of-round wheels

The dynamic response of a railway track under a moving train in the presence of a defective wheel is studied. The goal of this study is to establish an efficient dynamic model for wheel tread defect analysis. The wheel irregularities which influence the track vibration characteristics are classified in 2 major types: periodic out-of-roundness and local defect. While the periodic irregularities are distributed all around the wheel, the local defects such as wheelflats have more impact on the dynamic response. The influence of each defect depends on its geometrical characteristics and the model parameters. The separate effects of different irregularities have been the subject of many previous researches. However the contribution of each defect to a coupling of irregularities was not as much considered. For a comprehensive analysis of all types of defects, an efficient global model is presented. It includes 3 sub-models for vehicle, contact force and track. The time-domain responses of the model are evaluated in comparison to those of a finite element model. It is shown that the semi-analytical model of the track keeps a good precision while being less time consuming. The results of the global model for different types of wheel irregularities are presented