Influence of tread inertia during deformation using a detailed numerical tyre/road contact model

Predicting tyre/road interaction processes like stick-slip and stick-snap and their resulting tyre/road noise requires detailed information about the road surface and the dynamics of the tread at the interface. Inertial effects in the tread layer are neglected in many of the existing tyre/road interaction models without explicit justification. The objective of this paper is to investigate the potential importance of these effects for the case of a tread material indenting a rough road surface in the normal direction. A comprehensive numerical contact model operating in the time-domain which includes the effects of interfacial details is used for this purpose. Contact forces at the surface of the tread and at the interface between the tread and the belt are studied in the normal direction during the simulated loading. The inertial case, with a tread impulse response extending in time, is compared with the non-inertial case where the corresponding quasi-static response is used. Results show that the difference in contact force and contact stiffness between a quasi static and a dynamic simulation is small for loading rates that could be found in typical tyre/road contact conditions. Only for extremely high loading rates is there a significant difference. This work implies that inertial effects of the tread are negligible for the local tread response when simulating normal tyre/road contact situations.