VERIFICATION OF RABINOWICZ’ CRITERION BY DIRECT MOLECULAR DYNAMICS MODELING

In the paper we use direct molecular dynamics modeling to validate the criterion for formation of wear debris proposed by E. Rabinowicz in 1958. A conventional molecular dynamics using a classical Tersoff’s potential was applied to simulate the sliding behavior within a thin film corresponding to a tribofilm formed from silica nano-particles in amorphous-like state. The simulation was carried out by varying the initial temperature and the spatial size of the simulated crystallite. The results show the change in sliding behavior of silica-based tribofilm depending on the temperature and the size parameter of the system under consideration. Thus increasing the temperature provides smooth sliding while at moderate conditions wear process can occur via debris formation. Our estimations show good correlation between predicted critical size of the simulated system and calculated energetic characteristics.

GENERALIZED ARCHARD LAW OF WEAR BASED ON RABINOWICZ CRITERION OF WEAR PARTICLE FORMATION

According to the Archard law of adhesive wear, the wear volume is proportional to the normal force, the sliding distance, and inversely proportional to the hardness of the softer of contact partners. This law does not contain any properties characterizing “adhesion” of materials, e.g. the work of separation, either inside of the material or at the interface. The criterion for formation of wear particles, first formulated by Rabinowicz in 1958, on the contrary, is based on the interplay of elastic energy and work of adhesion and contains as governing parameters the modulus of elasticity, hardness and the work of separation. Following recent advances in understanding and simulation of wear, we discuss the ways how both laws could be melted together to a “generalized” Archard-Rabinowicz law of wear.