Do uniform tangential interfacial stresses affect adhesion?

TL;DR

This paper demonstrates through theoretical analysis that uniform tangential interfacial stresses do not influence adhesion in sliding contacts, aligning with experimental observations and explaining the effects of sliding velocity on contact area and adhesion.

Contribution

The study provides a theoretical proof that tangential stresses do not affect adhesion, clarifying experimental results and the impact of sliding velocity on contact behavior.

Findings

Tangential stresses do not alter the adhesive contact area.

Experimental contact area remains constant during sliding at low velocities.

Increased sliding speeds reduce adhesion due to bond density decrease or stress fluctuations.

Abstract

We present theoretical arguments, based on linear elasticity and thermodynamics, to show that interfacial tangential stresses in sliding adhesive contacts does not affet at all the adhesive behavior of the system, which then follows the classical JKR solution. Our finding explains the experimental observation of Vorvolakos and Chaudhury in 2003, who found that the contact area of a PDMS sphere remains constant during sliding and is in agreement with the JKR solution, at least up to velocity of 1mm/s, and of Carpick et al. Carpick, who observed that the friction force between a platinum-coated atomic force microscope (AFM) tip and the surface of mica in ultrahigh vacuum (UHV) varies with load in proportion to the contact area predicted by the Johnson-Kendall-Roberts (JKR). We show that a reduction of the contact area, experimentlly observed at higher sliding speeds, can be caused by a reduction of the density of adhesive bonds as the velocity is increased, or caused by the repulsive energy term associated with the stress spatial fluctuation at the interface. This may explain why adhesion is completely masked at relatively large sliding velocities. This version of the paper follows the publication of the Corrigendum: Nicola Menga, Giuseppe Carbone, Daniele Dini: Corrigendum to "Do uniform tangential interfacial stresses enhance adhesion?" [Journal of the Mechanics and Physics of Solids 112 (2018) 145--156], Journal of the Mechanics and Physics of Solids, 133, 103744, https://doi.org/10.1016/j.jmps.2019.103744, available on line since 8 October 2019.