Analysis of stress drop behavior for stick-slip friction based on total reflection observation experiment

This paper employed an experimental system based on the total reflection method to study the contact interface behavior during the stress drop process of stick-slip friction. The two-stage drop behavior was found for the first time, namely, the tangential load during the stick-slip stress drop underwent two successive drops in different rates and magnitudes, instead of a single drop. A critical location at the contact interface, where the contact areas on both sides of this location exhibited different contact behaviors during stress drop events, was found. An image recognition method was present to identify the boundary between the stick and sliding zones of the interface, the impact of stress drop events on interface contact, and the propagation velocity and direction of rupture fronts. Finally, the mechanism for the interesting phenomenon described in this paper was preliminarily discussed. The research may be useful for better understanding the stick-slip friction and its stress drop events.