A Revised Continuous Observation Length Model of Rough Contact without Adhesion

Abstract

The real contact area of rough surfaces has significant importance in many engineering applications, such as tribology, wear, lubrication and seals. A continuous observation length-dependent mechanic model of rough contact without adhesion is proposed, which assumes that the rough surface is divided into ideal subplanes. However, the model ignores the elastoplastic deformation of asperities, and the standard deviation of ideal subplanes’ heights is assumed to vary linearly with continuous observation length, which is not precise for all the surface fractal dimensions. In this work, a revised continuous observation length model is proposed with elastic, elastoplastic and fully plastic stages. The expressions of force and real contact areas are derived. For surfaces with different fractal dimensions, the quadratic polynomial, cubic polynomial and power relationships between standard deviation and observation length are proposed, respectively. In addition, the influences of the dimensionless observation length, fractal dimension and equivalent elastic modulus on the real contact areas in different contact stages are also analyzed. It can be concluded that the quadrate real contact area decreases as the dimensionless observation length decreases, which can be applied to the percolation theory for leak seal problems.

Analysis, Modeling and Experimental Study of the Normal Contact Stiffness of Rough Surfaces in Grinding

“…Wenzhen xie et al [21] simulated the microscopic contact behavior of rough surfaces through molecular dynamics and established a semi-analytical model based on this. Lan zhang et al [22], based on statistical methods, proposed a modified rectangular microconvex model for the continuous observation of the length of non-adherent rough contact. Guangbin yu [23] comprehensively analyzed the geometric structure and mechanical properties of elliptical concave and convex points on rough surfaces, and established a contact mechanical model of elliptical asperities on rough surfaces containing elliptical concave and convex points.…”

“…Wenzhen xie et al [21] simulated the microscopic contact behavior of rough surfaces through molecular dynamics and established a semi-analytical model based on this. Lan zhang et al [22], based on statistical methods, proposed a modified rectangular microconvex model for the continuous observation of the length of non-adherent rough contact.…”