Onset of sliding of elastomer multicontacts: failure of a model of independent asperities to match experiments

TL;DR

This study tests a microjunction asperity model against new experimental data on elastomer interface sliding, finding that the model fails to match observed behavior despite experimental constraints.

Contribution

It provides a critical evaluation of the asperity model using detailed local measurements, revealing its limitations in accurately predicting interface failure.

Findings

The asperity model does not quantitatively match experimental measurements.

Experimental data on microjunction contact areas challenge the model's assumptions.

Model limitations suggest the need for more comprehensive or different modeling approaches.

Abstract

Modelling of rough frictional interfaces is often based on asperity models, in which the individual behaviour of individual microjunctions is assumed. In the absence of local measurements at the microjunction scale, quantitative comparison of such models with experiments is usually based only on macroscopic quantities, like the total tangential load resisted by the interface. Recently however, a new experimental dataset was presented on the onset of sliding of rough elastomeric interfaces, which includes local measurements of the contact area of the individual microjunctions. Here, we use this more comprehensive dataset to test the possibility of quantitatively matching the measurements with a model of independent asperities, enriched with experimental information about the area of microjunctions and its evolution under shear. We show that, despite using parameter values and behaviour laws constrained and inspired by experiments, our model does not quantitatively match the macroscopic measurements. We discuss the possible origins of this failure .