Wheel-rail Noise Generation, Part V: Inclusion Of Wheel Rotation

Abstract

Previous models of wheel-rail noise generation have all been based on the dynamical behaviour of stationary wheels and rails. In this paper the effects of wheel rotation have been included into the theory of wheel rail noise generation. The relevant equations are derived on the assumption that the surface roughness provides a random displacement input to the system. The inclusion of the rotation into the interaction model gives an improved representation of the wheel web response, containing no anti-resonance dips. The major peaks in this motion, the most important acoustically, appear as single peaks close to wheel resonance frequencies, and these are significantly closer to the corresponding resonance frequencies than was the case for the model based on a non-rotating wheel. Viewed from the excitation point, the resonance peaks each split into two, which correspond to two contra-rotating waves. The predictions indicate that the resulting wheel vibration should contain no distinct node lines located either in the wheel or in space, a feature which is confirmed in practice. The predictions of the lateral response of the wheel tyre are improved compared to those for the non-rotating case.