Please use this identifier to cite or link to this item: doi:10.22028/D291-27516
Title: Contact-Patch-Size Distribution and Limits of Self-Affinity in Contacts between Randomly Rough Surfaces
Author(s): Müser, Martin H.
Wang, Anle
Language: English
Title: Lubricants
Volume: 6
Issue: 4
Publisher/Platform: MDPI
Year of Publication: 2018
Free key words: surface roughness
contact mechanic
Amontons’ law
Archard’s law
DDC notations: 600 Technology
Publikation type: Journal Article
Abstract: True contact between solids with randomly rough surfaces tends to occur at a large number of microscopic contact patches. Thus far, two scaling regimes have been identified for the number density n(A) of contact-patch sizes A in elastic, non-adhesive, self-affine contacts. At small A, n(A) is approximately constant, while n(A) decreases as a power law at large A. Using Green’s function molecular dynamics, we identify a characteristic (maximum) contact area Ac above which a superexponential decay of n(A) becomes apparent if the contact pressure is below the pressure pcp at which contact percolates. We also find that Ac increases with load relatively slowly far away from contact percolation. Results for Ac can be estimated from the stress autocorrelation function Gσσ(r) with the following argument: the radius of characteristic contact patches, rc, cannot be so large that Gσσ(rc) is much less than p2cp. Our findings provide a possible mechanism for the breakdown of the proportionality between friction and wear with load at large contact pressures and/or for surfaces with a large roll-off wavelength.
DOI of the first publication: 10.3390/lubricants6040085
Link to this record: urn:nbn:de:bsz:291--ds-275162
ISSN: 2075-4442
Date of registration: 22-Mar-2020
Faculty: NT - Naturwissenschaftlich- Technische Fakultät
Department: NT - Materialwissenschaft und Werkstofftechnik
Professorship: NT - Prof. Dr. Martin Müser
Collections:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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