# Elasticité et rhéologie d'une interface macroscopique : du piégeage au frottement solide

Abstract : We study the frictional properties of a multicontact interface (MCI), composed of a large set of microcontacts between the surface asperities of two macroscopic solids. We first investigate the sliding dynamics at a MCI under a harmonically modulated normal load. We show that the load modulation induces a decrease of the average friction force, and stabilizes sliding against stick-slip oscillations. The state- and rate-dependent friction model (SRF), which describes the sliding dynamics in terms of the competition between geometric aging by plastic creep of the microcontacts, interrupted by sliding, and interfacial rheology, does not account quantitatively for the observed effects. We successfully extend this model to account for the finite stiffness of the interface, which plays a crucial role in the coupling between normal load and friction force. In a second part, we study the interfacial response to a biased oscillating shear force, in order to obtain information about the crossover from static to dynamic regime at a frictional interface. We evidence, for force amplitudes close to the static threshold, the existence of a saturating creep response of the sheared interface. The SRF model alone cannot describe the creep dynamics, which suggests the existence of a structural aging mechanism acting in the nanometer-thick adhesive junction that forms the contact between asperities. To check this hypothesis, we perform a set of friction experiments at a rough/plane interface, allowing to probe accurately the interfacial rheology. We thus show unambiguously that the adhesive junction exhibits a behaviour which is very similar to that of sheared weak'' solids: it flows beyond a stress threshold, ages at rest, and is rejuvenated by motion.
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https://tel.archives-ouvertes.fr/tel-00001413
Contributor : Lionel Bureau <>
Submitted on : Friday, June 14, 2002 - 10:27:29 AM
Last modification on : Wednesday, December 9, 2020 - 3:10:43 PM
Long-term archiving on: : Friday, April 2, 2010 - 7:56:06 PM

### Identifiers

• HAL Id : tel-00001413, version 1

### Citation

Lionel Bureau. Elasticité et rhéologie d'une interface macroscopique : du piégeage au frottement solide. Dynamique des Fluides [physics.flu-dyn]. Université Paris-Diderot - Paris VII, 2002. Français. ⟨tel-00001413⟩

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