Characterizing the Evolution of Contact Area in Frictional Interfaces

Abstract

Seemingly static interfaces between two solids are in fact dynamic. These multicontact interfaces (MCIs) exert enormous stresses on tiny contact areas, causing time-dependent deformation. Though these phenomena are ubiquitous (e.g from micromachines to plate tectonics), their underlying mechanisms are not yet well understood. By constructing a novel apparatus, we may now take real-time, 2D measurements of the real contact area in an interface over a variety of normal loads and time steps. Given that the real contact area of an interface may be used as a proxy for frictional strength, this area based tribometer allows for an investigation into the underlying dynamics of frictional interfaces. Furthermore, by varying geometric and elastic properties of samples, we induce variations in the 2D structure of contact growth, which give insight into the mechanisms that produce deformations in frictional interfaces.