Dynamic contact law between a rolling pneumatic tyre and a single asperity

The dynamic contact between rolling tyres and road asperities is a major contributor to the vibrational and aerodynamic mechanisms at the origin of tyre/road noise. While determination of the dynamic contact law proves difficult, previous efforts to estimate the rolling noise were mostly based on the assumption that the static contact law is applicable in the dynamic case. This paper proposes a novel experimental study of the dynamic contact law accompanied by numerical verifications. A reduced-sized tyre is set rolling on the exterior surface of a cylindrical test rig simulating a road surface. A single asperity of simple geometric shape is screwed onto a force transducer mounted in the test rig. The peak normal force is thus measured to show the influences of various parameters such as the indentation depth and the asperity shape. The experimentally assessed dynamic contact law is then compared with the analytically calculated static one.