ИСТИНА

A model of adhesive contact is presented for two nominally flat surfaces, one of which is a plane surface of the elastic half-space and the other is a set of regularly arranged micro-asperities. Adhesion of two different natures is considered – molecular adhesion of dry surfaces associated with van der Waals forces and capillary adhesion of wet surfaces caused by liquid bridges between them. Methods of calculation of the contact characteristics at micro-scale such as real contact pressure and real contact area are developed, depending on the values of surface energy of the interacting bodies, relative humidity of the atmosphere, elastic properties of the half-space, and mutual influence of neighbor asperities. A method is proposed to calculate the effective adhesion pressure and effective work of adhesion for two nominally flat surfaces taking into account surface micro-relief. Based on the method proposed, a two-scale contact model is developed which makes it possible to analyze the influence of the characteristics of adhesion and geometric parameters of micro-relief (relative size of asperities, and distance between them) on the contact characteristics at macro-scale, such as nominal contact pressure, nominal contact area, and load-distance curve.