The Characteristics of Elastically Contacting Ideal Rough Surfaces

Abstract

The analysis of the elastic contact of ideal rough surfaces is presented in this paper. The rough asperities are assumed to be spherical with the same vertical height and spatial distance. The mutual influence of asperities is considered. Numerical results show that for the same load, the contact area is less than the Hertzian prediction, while the pressure distribution is still of a Hertzian type, but is increased to some extent. We find that the asperity interaction is associated with a parameter, called the “loading level,” which combines the surface texture, mechanical properties, and the nominal mean pressure. Of significant importance is the discovery of the variation of the reference plane position with the contact load. In the classical theory of rough contact (Greenwood and Williamson, 1966), the reference plane was in fact assumed to be in the mean line position. We prove that the location of the reference plane is determined by the number of contacting asperities and the loading level, thus making the analysis of the contact of rough surfaces somewhat complex.