Description: Percolation of Contact and Non-Contact: From Single-Wavelength Roughness to Self-Affine Surfaces

This title appears in the Scientific Report : 2015

Percolation of Contact and Non-Contact: From Single-Wavelength Roughness to Self-Affine Surfaces

The 1966 Greenwood-Williamson paper pioneered research in tribology by linking the contact mechanics of microscopic single-asperities to that of macroscopic, nominally flat surfaces. One important finding of their work was that the functional dependence of contact area on load at the macroscopic sca...

Personal Name(s):	Müser, Martin (Corresponding author)
	Dapp, Wolfgang
Contributing Institute:	Jülich Supercomputing Center; JSC
Imprint:	2015
Conference:	42nd Leeds-Lyon Symposium on Tribology, Lyon (France), 2015-09-07 - 2015-09-09
Document Type:	Conference Presentation
Research Program:	Computational Science and Mathematical Methods
	Publikationsportal JuSER

The 1966 Greenwood-Williamson paper pioneered research in tribology by linking the contact mechanics of microscopic single-asperities to that of macroscopic, nominally flat surfaces. One important finding of their work was that the functional dependence of contact area on load at the macroscopic scale can differ qualitatively from that at the microscopic scale.In our paper we also study the contrast between contact mechanics at macroscopic and microscopic scale, however, with an emphasis on the contact mechanics of saddle points, with and without adhesion. Specifically, we study how open channels – allowing a fluid to flow through an interface – close with increasing load. To this end we first study how a single open channel closes and gets blocked when the local pressure increases (or the strength of the adhesive interaction, which has a similar effect). Blockage essentially happens when two previously isolated contact patches coalesce to a single patch. Interestingly, the contact mechanics of saddle points shares much similarity to that of Hertzian contacts. In a second step, we rationalize the closing of open fluid channels in contacts of macroscopic, nominally flat self-affine surfaces in terms of the insight gained at the microscopic scale.