A novel methodology to predict sliding and rolling friction of viscoelastic materials: Theory and experiments

In this paper we propose a novel methodology to numerically investigate the steady-state sliding or rolling contact of viscoelastic materials, and in particular to calculate the viscoelastic contribution to friction. The implemented boundary element method relies on a very general mathematical formulation, able to deal either with rolling or sliding contact, and more importantly, able to handle real viscoelastic materials with a large number of relaxation times (e.g. tire rubber), thus overcoming the limitations of other analytical and numerical techniques. The proposed methodology is, then, employed to study the steady state rolling of a smooth rigid sphere on a standard linear viscoelastic solid, and to investigate the rolling contact of a rigid sphere moving on a styrene butadiene rubber. Numerical predictions are compared with existing theoretical investigations and with experiments. In both cases we find an almost perfect agreement.