Wear modeling and the third body concept

Many laws already exist for wear, but few are really predictive. In order to better understand the wear process, classical wear models are compared to the third body concept. This concept emphasizes that particle detachment mechanisms, the flow of these particles inside the contact, and their ejection from the contact have to be considered in order to describe wear effectively. An analytical demonstration is proposed, that considers the particle detachment process and the particle ejection process separately. These two processes are then linked by a mass equilibrium equation. In continuous sliding, a steady-state wear process can be identified in which the mass of third body particles in the contact remains constant. The source flow and the wear flow (representing, respectively, particle detachment and particle ejection) become equal and constant in time. Initially presented via numerical investigations, this analytical model is then confirmed by simple experiments.