On adhesive contact between spheres with rolling adhesion

The tendency of relative motion via rolling between contacting objects exists in various aspects of industry and nature because, in many practical situations, forces and moments may be simultaneously induced at the contacting interfaces. Due to the presence of adhesion, which may be prominent on small scales, research on contacts with the tendency to roll, termed herein as rolling adhesion, is very limited. In the present work, a novel double-Hertz model is developed for adhesive contact between spherical objects subjected to the combined action of normal forces and moments. The results from the new model agree well with available numerical simulations and experimental results. It has been demonstrated that the contact behavior with the effect of rolling adhesion seemingly resembles that of conventional adhesive contact, but the applied moment may impact the pull-off force and may even induce novel contact instability if large enough. The resistance moment at the interface has also been obtained analytically, which is proportional to adhesion hysteresis and contact area. Given the applicability to the full range of the Tabor parameter and nonsingular stresses involved, these results might shed light on adhesive contacts with rolling adhesion and help to characterize them better than existent models.