A study of surface friction and particle friction between rough surfaces

Abstract

Based on contact mechanics and friction theory, this work establishes a new three-body friction model that considers the adhesive friction, summit deformation friction, ratchet friction, and deformation friction of particles. In MEMS and precision machines, particles are often present at contact interfaces. The adhesion force between those particles gives rise to the variation of adhesion and friction at the contact region. In this paper, a three-body friction model for rough surfaces with particles is proposed to evaluate the effects of particles between surfaces on contact characteristics. The results show that the ratio of the particle size and roughness, x/ R q , dominates the friction for low mean separation between rough surfaces at the same plasticity index. The total friction coefficient decreases with decreasing plasticity index or the ratio x/ R q . Beyond the critical value of mean separation ( d/ σ) C, the main factor that affects total friction is surface friction. The critical dimensionless separation ( d/ σ) C decreases with decreasing plasticity index or the ratio x/ R q .