Self-Affine Elastic Contacts: Percolation and Leakage

TL;DR

This paper investigates how elastic deformation affects fluid leakage at rough interfaces, demonstrating that deformation reduces percolation and leakage, and proposes a combined theoretical approach for accurate leakage estimation.

Contribution

It introduces a novel analysis of elastic deformation effects on contact percolation and leakage, integrating Persson's theory with an effective-medium approximation.

Findings

Elastic deformation lowers the percolation threshold for contact patches.

Deformation suppresses leakage even away from percolation threshold.

A combined theoretical model accurately estimates leakage.

Abstract

We study fluid flow at the interfaces between elastic solids with randomly rough, self-affine surfaces. We show by numerical simulation that elastic deformation lowers the relative contact area at which contact patches percolate in comparison to traditional approaches to seals. Elastic deformation also suppresses leakage through contacts even far away from the percolation threshold. Reliable estimates for leakage can be obtained by combining Persson's contact mechanics theory with a slightly modified version of Bruggeman's effective-medium solution of the Reynolds equation.