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

摘要

Previous studies have shown correlations between the properties of multi-asperity roadsurfaces and CPX noise spectra below 1000 Hz. Noise increases when the mean distanceand the mean relative height between asperities increase. It decreases when the density ofasperities increases. The aim of the study is to assess the origin of these correlations bymeans of the multi-asperity tyre/road contact model developed by the authors. For thispurpose a number of artificial road surfaces composed of academic asperities of simpleshapes (spherical, conical or cylindrical) are generated. The dynamical contact forces arecalculated over several loops for a slick tyre rolling at different speeds. The spectra for aperiodic road surface clearly show that the excitation frequency of the tyre within thecontact area is directly due to the speed and the distance between asperity tips in the rollingdirection. For randomly distributed artificial surfaces, broad band spectra are obtainedwith a cut off frequency linked to distance between successive contacts in the rollingdirection while the mean relative height has few influence. The results are discussed andcompared with spectra of contact stresses for real road surfaces within the framework oftyre/road noise.