The dependence of the dry friction threshold on rupture dynamics

TL;DR

This paper shows that the static friction threshold is not a fixed material property but varies with external loading and rupture dynamics, affecting stress drops during sliding.

Contribution

It demonstrates experimentally that the friction threshold depends on rupture dynamics and external loading configurations, challenging the notion of a constant static friction coefficient.

Findings

Friction coefficient varies with external loading conditions.

Stress drops are linked to rupture dynamics.

Friction behavior is influenced by interface rupture processes.

Abstract

The static friction coefficient between two materials is considered to be a material constant. We present experiments demonstrating that the ratio of shear to normal force needed to move contacting blocks can, instead, vary systematically with controllable changes in the external loading configuration. Large variations in both the friction coefficient and consequent stress drop are tightly linked to changes in the rupture dynamics of the rough interface separating the two blocks.