Complex eigenvalue analysis and parameters analysis to investigate the formation of railhead corrugation in sharp curves

Rail corrugation, a quasi-sinusoidal irregularity of the rail head, is a common issue experienced throughout the railway networks worldwide. It generally leads to high wheel-rail dynamic loads, increased noise emission, and poor ride comfort. Most commonly, rail corrugation is likely to develop on sharp curves. This paper aims to study the numerical feasibility of the prediction of self-excited vibrations for the study of rutting corrugation formation without excitation from initial rail roughness. A finite element model for the prediction of the self-excited vibrations of the leading wheelset-rails system in a sharp curve has been developed in ABAQUS. The friction coupling between the wheel and rail is taken into account. It is assumed that the lateral creep forces between wheel and rail are quasi-saturated. The proposed model is applied to investigate the effect of several structural factors on self-excited vibrations occurrence. The obtained numerical results match closely with the typical wavelength of rutting corrugation observed in the field sites and the experimental evidence on rutting corrugation. It has been found out that the interaction effect of the wheelset cross-section and the track gauge has a significant influence on self-excited vibrations. For a typical European wheelset cross-section, self-excited vibrations only occurred under the widened track gauge. For the studied Chinese wheelset, self-excited vibrations occurred, however, only under the standard track gauge. Therefore, following the assumptions underlying the analysis, wheelset cross-section might be an inhibitor factor at a particular track gauge. A parameter sensitivity analysis shows that the friction coefficient is linearly correlated with the system's instability and the frequency of the unstable modes of vibration