ANALYSIS OF PHENOMENA IN REAL CONTACT SPOTS DUE TO DYNAMIC FORCING UNDER TANGENTIAL MICROMOTION

摘要

Currently, there are two basic concepts concerning surface damage processes: one connected with surface activation, which involves an increase in free energy in a tribological system, and the other connected with surface passivation, when free energy decreases. In oscillating tribocontacts, we observe intensive formation of secondary structures of type I (Fe_2O_3, Fe_3O_4) and type II (FeO). Experimental and theoretical studies were conducted to determine the contact between a sphere and a plane, which is the most suitable system for simulating small-amplitude fretting (～0-3 microns). In a single point contact, we can observe all types of local surface damage in the radial direction depending on the relative slip amplitude (practically, from ~ 0), from absolutely elastic interaction in the central contact zone to the slip amplitude at the margin of the contact area in micrometers. It is very important to implement numerical and continuous integration of the stick-slip zones and calculate the contact stress and strain of the surface layer. Analyzing the influence of thermal fluctuation on the strength of materials, we can determine the parameters of activation of the surface damage at small-amplitude fretting.