Solid Third Body Analysis Using a Discrete Approach: Influence of Adhesion and Particle Size on Macroscopic Properties

The dynamics of solid third bodies sheared between two rubbing bodies is far from being understood. Yet, this interface plays a prominent role in the velocity accommodation and in the load transmission. In the present paper, a simple model, which uses the Distinct Element Method, is operated in order to understand phenomena occurring in dry contact. In this model, the solid third body is considered as an aggregate of discrete interacting particles. Inter-particle forces are determined by force-displacement law and trajectories are calculated using the Newton’s second law. The global behavior of the simulated contact can be analyzed through the evolution versus time of characteristic parameters calculated by averaging over all the particles. The model is used to study the effect of particle size and inter-particle forces. The influence of particle size is studied in presence of repulsive force (based on Hertz contact model), and in presence of adhesive force (based on JKR contact model). Some promising results are highlighted. In particular, with the boundary conditions chosen in this paper, it is shown that the particle size has a weak influence when inter-particle forces are repulsive but has a dramatic influence when inter-particle adhesion is considered: solid third body goes from a quasi-fluid to a quasi-solid behavior.