Modelling of Wheel/rail Squeal Noise in Curves from Mono-Harmonic Vibratory Limit Cycles

Most of the works in the literature agree to attribute the generation of wheel/rail squeal noise in curves to the important lateral slip imposed in the curve and the resulting instabilities. In models, the occurrence of the phenomenon is thus generally studied through a stability analysis based on the linearization of the contact forces. Despite its undeniable interest, the stability analysis does not allow the prediction of the amplitudes of the nonlinear self-sustained vibrations resulting from the instabilities. These nonlinear vibrations are most often calculated using a numerical integration of the dynamic equations of the system in the time domain. Some authors have proposed simplified methods allowing a direct calculation of stationary regimes, but limited to a reduced modal description of the system dynamics. In this presentation, an original method is proposed to determine approximate limit cycles from the wheel/rail contact mobilities expressed in the frequency domain. The contact condensation allows to be both more general and more functional to describe the dynamics of structures, in particular the one of the rail. Assuming a mono-harmonic vibratory cycle, the corresponding amplitude is determined from a power balance and the squeal level at the considered pulsation is obtained from analytical radiation factors.