Independent friction-restitution modeling of two-disk collisions

The oblique collisions between two axisymmetric disks moving on a flat horizontal surface are described in terms of impact modeling based on the assumption that normal and tangential restitution mechanisms operate independently of friction. Describing these mechanisms in terms of the usual Coulomb formulation, the model allows for an interpretation of some “anomalous” experimental data reported in the literature. These experimental data, corresponding to the variation of the coefficients of friction and tangential restitution with the impact angle, remained unexplained in classic formulations, are understood within the framework of the independent friction-restitution closure. Experimental data for metallic coins are in agreement with that formulation, including rolling friction effects.