Tyre/road noise: Influence of multi-asperity road surface properties on tyre-road contact stresses

This paper deals with the relation between properties of road surfaces and measured tyre/road noise. A number of artificial road surfaces composed of academic asperities of simple shapes (spherical, conical or cylindrical) are generated. The dynamical contact forces are calculated over several loops for a slick tyre rolling at different speeds. A multi-asperity contact model developed by the authors is used. The spectra for a periodic road surface clearly show that the excitation frequency of the tyre within the contact area is directly due to the speed and the distance between asperity tips in the rolling direction. For randomly distributed artificial surfaces, broad band spectra are obtained with a cut off frequency linked to distance between successive contacts in the rolling direction while the mean relative height has few influence. The results are discussed and compared with spectra of contact stresses for real road surfaces within the framework of tyre/road noise.