Formation of heterogeneous spatial structures in a boundary lubrication layer during friction

Abstract

This paper presents a synergetic model describing the boundary friction of two atomically smooth solid surfaces separated by an ultrathin lubricant layer. The model is constructed using the Lorenz system of equations, which is parameterized by shear stresses, shear strains, and the lubricant temperature. Given the spatial inhomogeneity of these parameters, it is shown that a structure with two types of domains is formed during friction on the contact plane. Time dependences of the fractal dimensions of the domain distributions over the contact plane are calculated, and it is shown that there exists a time when the fractal dimensions take minimum values. During the evolution, the system tends to a homogeneous state in which the shear stresses over entire contact area have a constant value which determines the relative velocity of motion of the friction blocks.