Surface coupling effects on contact mechanics: contact area and interfacial separation between an elastic solid and a hardsubstrate with randomly rough, self-affine fractal surfaces

The objective of this study is to investigate boththe contact area and the interfacial separation between twosurfaces. Both surfaces are considered to be rough, one ofthem being elastic and the other one hard. The work isbased on an extended version of Persson’s model of contactmechanics to study the behavior of the contact area, theinterfacial separation and the pressure distribution. Theresults are compared with the case merely the hard substrateis rough. It is seen that introducing a roughness in theelastic surface decreases the real contact, if the surfaces areuncorrelated. A positive (negative) correlation increases(decreases) the real contact. A reverse pattern occurs forthe width of the pressure distribution, as well as theinterfacial separation (at equal pressures).