Interfacial separation between elastic solids with randomly rough surfaces: comparison of experiment with theory

TL;DR

This study compares experimental measurements and theoretical predictions of the average separation between an elastic rubber and a rough hard surface under varying pressure, confirming the exponential relationship between pressure and separation.

Contribution

It provides experimental validation for the theoretical model describing interfacial separation and pressure relationship for elastic solids with rough surfaces.

Findings

Experimental results agree with the exponential pressure-separation law.

The effective repulsive pressure follows p ∝ exp(-u/u0).

The theory accurately predicts the measured separation under different pressures.

Abstract

We study the average separation between an elastic solid and a hard solid with a nominal flat but randomly rough surface, as a function of the squeezing pressure. We present experimental results for a silicon rubber (PDMS) block with a flat surface squeezed against an asphalt road surface. The theory shows that an effective repulse pressure act between the surfaces of the form p proportional to exp(-u/u0), where u is the average separation between the surfaces and u0 a constant of order the root-mean-square roughness, in good agreement with the experimental results.