Functional properties of rough surfaces from an analytical theory of mechanical contact

The basic ideas behind a contact mechanics theory for randomly rough surfaces are presented. The theory is based on studying the interface at increasing magnification. At the lowest magnification, no surface roughness can be detected and the nature of the contact between two solids in this limit can be determined using standard numerical methods (e.g., FEM). The theory predicts how the surface roughness influences (or modifies) the contact stress distribution and the interfacial gap. The theory is flexible and can be applied to elastic, viscoelastic, and elastoplastic solids, as well as layered materials. Applications to leakage of seals, contact stiffness, the electric and thermal contact resistance, rubber friction, adhesion, and mixed lubrication are presented.