A Flexible Ring Tyre Model for Normal Interaction

A physical – numerical tyre model has been developed. The whole model allows to obtain the tyre – road interactions which can be used in vehicle dynamics simulations. In this paper its capabilities in terms of normal interaction analysis are presented. The tyre normal interaction, i.e. the relationship between the normal load and the normal deflection, influences the tangential (longitudinal plus lateral) one, which determines the vehicle’s handling behaviour. The parameters used in the model depend on the structure of the tyre and they can be measured on the real tyre. The tyre has been schematized as composed by a flexible belt, by the sidewalls and by a rigid ring (rim). The flexible belt is composed by a number of lumped masses linked by extensional and bending stiffnesses and dampers. The tyre model has been developed using the finite segment method. Using this method it is possible to include in the tyre simulations various non-linear structural effects due to large displacements and rotations. The model allows to simulate both steady state and transient conditions.