Control of Static Friction by Designing Grooves on Friction Surface

TL;DR

This paper investigates how designing grooves on a friction surface can reduce static friction by combining numerical simulations and theoretical analysis, revealing the influence of groove size on precursor slip and static friction.

Contribution

It introduces a novel numerical and theoretical framework linking groove design to static friction reduction through precursor slip analysis.

Findings

Static friction coefficient decreases with larger grooves.

Precursor slip propagates before bulk sliding.

Theoretical model predicts a scaling law for critical slip area.

Abstract

This study numerically investigated the friction of viscoelastic objects with grooves. A 3D viscoelastic block with grooves on a rigid substrate is slowly pushed from the lateral side under uniform pressure on the top surface. The local friction force at the interface between the block and the substrate obeys Amontons' law. Numerical results obtained using the finite element method reveal that the static friction coefficient decreases with increasing groove width and depth. The propagation of the precursor slip is observed before bulk sliding. Furthermore, bulk sliding occurs when the area of slow precursor slip reaches a critical value, which decreases with increasing groove size. A theoretical analysis based on a simplified model reveals that the static friction coefficient is related to the critical area of the precursor, which is determined by the instability of the precursor. A scaling law for the critical area is theoretically predicted, and it indicates that the decrease in the effective viscosity due to the formation of the grooves leads to a decrease in the static friction coefficient. The validity of the theoretical prediction is numerically confirmed.