An asperity-based statistical model for the adhesive friction of elastic nominally flat rough contact interfaces

Xu, Y., Scheibert, J., Gadegaard, N. and Mulvihill, D. M. (2022) An asperity-based statistical model for the adhesive friction of elastic nominally flat rough contact interfaces. Journal of the Mechanics and Physics of Solids, 164, 104878. (doi: 10.1016/j.jmps.2022.104878)

Abstract

Contact mechanics-based models for the friction of nominally flat rough surfaces have not been able to adequately capture certain key experimentally observed phenomenona, such as the transition from a static friction peak to a lower level of sliding friction and the shear-induced contact area reduction that has been observed in the pre-sliding regime especially for soft materials. Here, we propose a statistical model based on physically-rooted contact mechanics laws describing the micromechanics of individual junctions. The model considers the quasi-static tangential loading, up to full sliding, of the contact between a smooth rigid flat surface and a nominally flat linear elastic rough surface comprising random independent spherical asperities, and accounts for the coupling between adhesion and friction at the micro-junction level. The model qualitatively reproduces both the macroscopic shear-induced contact area reduction and, remarkably, the static friction peak without the need to explicitly introduce two different friction levels. It also demonstrates how the static friction peak and contact area evolution depend on the normal load and certain key microscale interface properties such as surface energy, mode mixity and frictional shear strength. “Tougher” interfaces (i.e. with larger surface energy and smaller mode mixity parameter) are shown to result in a larger real contact area and a more pronounced static friction peak. Overall, this work provides important insights about how key microscale properties operating at the asperity level can combine with the surface statistics to reproduce important macroscopic responses observed in rough frictional soft contact experiments.

• Item Type: Articles
• Additional Information: This work is supported by the Leverhulme Trust through Project Grant “Fundamental mechanical behavior of nano and micro structured interfaces” (RPG-2017-353), the National Natural Science Foundation of China (Grant No. 52105179), and LABEX MANUTECH-SISE (ANR-10-LABX-0075) of Université de Lyon, within the program Investissements d’Avenir (ANR-11-IDEX-0007) operated by the French National Research Agency (ANR) .
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Mulvihill, Dr Daniel and Gadegaard, Professor Nikolaj
• Authors: Xu, Y., Scheibert, J., Gadegaard, N., and Mulvihill, D. M.
• College/School: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Journal Name: Journal of the Mechanics and Physics of Solids
• Publisher: Elsevier
• ISSN: 0022-5096
• ISSN (Online): 1873-4782
• Published Online: 01 April 2022
• Copyright Holders: Copyright © 2022 Elsevier Ltd.
• First Published: First published in Journal of the Mechanics and Physics of Solids 164: 104878
• Publisher Policy: Reproduced in accordance with the publisher copyright policy