Normal impact of rough surfaces in presence of adhesion

The paper describes a theoretical study of normal impact between solids with small-scale surface asperities. An elastic-plastic impact model is used to study the normal impact between rough surfaces in presence of surface forces. The well-established elastic and plastic adhesion indices are used to consider the different conditions arising out of varying impact velocity and material parameters. The study shows that the coefficient of restitution is affected by material-properties, surface-topography and impact velocity. Results clearly indicate that high impact velocity is desirable in order to achieve low coefficient of restitution. However, there are certain combinations of material properties and surface conditions, given by the choice of adhesion indices, where coefficient of restitution falls to a very low value.