Modelling Non-Linear Contact Stiffness in Tyre/Road Contact

Paper i proceeding, 2007

Noise generation, rolling resistance, wear, and grip are determined by the tyre/road interaction. The small-scale surface geometry gives an area of real contact that increases with load over the interface leading to a non-linear relation between load and indentation depth for the interacting objects. The small length-scales of the contact geometry have traditionally been neglected in numerical tyre/road interaction models. This paper presents a step towards refinement of an existing tyre/road noise model by considering the small-scale geometry via a thin interfacial layer. A model for calculating the interfacial stiffness from road surface geometry and tread stiffness data is proposed. The interfacial stiffness is incorporated as non-linear springs in a numerical contact model based on a spatial discretisation of the contact geometry. Results of load-indentation relations and contact stiffness are presented for a single tread block in contact with a road surface. The results show that the contact stiffness of a tread block is substantially lower than the stiffness given by the bulk modulus of the objects. The contact stiffness varies substantially for typical variations in load and indentation depths that appear in the tyre/road contact.