This report examines the noise produced by the action of lorry tyres rolling on road surfaces and attempts to identify both the main sources and the mechanism of noise generation. A parametric study showed the rolling speed of the tyre was the main factor affecting the overall levels of tyre noise. Other factors of importance were wheel loads, tyre tread and road surface pattern, tyre construction and materials, acoustic absorption by the road surface and the presence of surface water. The study of sources established tyre surface vibration as the main source of tyre noise and other sources including 'air pumping' and aerodynamic noise were not found to contribute significantly to the overall levels on conventional road surfaces. Tyre vibration was found to be associated with the slip of the tread elements in the contact zone, the degree of slip being, largely, controlled by the frictional adhesion between the tyre and the road surface and the deformation of the tyre tread. (Author/publisher)
Samenvatting