Dynamic Stiction Mode by Friction Vector Rotation

TL;DR

This paper investigates a sliding system with anisotropic stiffness, revealing a novel 'dynamic stiction' mechanism where the friction force vector rotates during slow creep and rapid slip, challenging traditional stick-slip understanding.

Contribution

It introduces the concept of dynamic stiction, showing that apparent sticking is due to force vector rotation rather than true static friction.

Findings

Friction force remains nearly constant during the apparent stick phase.

The force vector rotates in the sliding plane during slow creep.

Rapid slip follows the slow creep phase, driven by force vector rotation.

Abstract

We numerically study a simple sliding system: a rigid mass pulled by a spring with a strong in-plane stiffness anisotropy and a small misalignment angle. Simulations show that the apparent stick phase appearing in this system is in reality a phase of very slow creep, followed by a rapid sliding, slip. Surprisingly, the absolute value of the friction force remains almost constant from the very beginning of the stick phase, merely rotating in the sliding plane. We call this specific mechanism of apparent stick due to rotation of the force vector "dynamic stiction".