ABSTRACT

The tire is the only contact of the vehicle with the road, thus handling and safety of the vehicle depend on dynamic forces i.e. lateral, tangential and cornering, generated between the tire and road contact patch. As the tread, the part of tire which comes into contact with the road, is made of rubber, hence it is important to understand the tread rubber friction characteristics with the corresponding contact surface. Friction proper-ties of rubber change with contact pressure, contact slip velocity and rubber surface temperature. It is important to incorporate this tire-road-interaction accurately into Finite Element Analysis (FEA) tools that analyze tire performance in dynamic conditions. FEA tools help tire designers and material developers to identify right material, design and construction parameters of the tire in an early design stage of the tire for achieving desired tire characteristics.It is observed during actual testing of tires that contact pressure, temperature and slip velocity on the contact surface of the tire are not constant. As per rubber friction experimental studies, the coefficient of friction changes with the change of the above-mentioned variables. Therefore, in order to accurately predict dynamic forces on the tire through FEA, modelling of tread rubber friction under these variable conditions is important.In the current study, the characterization of tire tread rubber has been carried out to obtain the friction coefficient with respect to changes of temperature, slip velocity and contact pressure. These variable friction values have been modelled by a suitable friction model and incorporated into an FE-simulation for tires. The simulation results have been compared to actual testing of the tire for validation purpose. Improvement in FEA predictions with respect to constant friction conditions have been compared.