Adhesion between elastic solids with randomly rough surfaces: comparison of analytical theory with molecular dynamics simulations

TL;DR

This study compares molecular dynamics simulations with Persson's contact mechanics theory to analyze adhesion between elastic solids with rough surfaces, finding good agreement and exploring effects like hysteresis in curved contacts.

Contribution

It provides a detailed comparison between MD simulations and analytical theory for rough surface adhesion, highlighting the effects of finite size and long-range interactions.

Findings

Good agreement between MD and theory for interfacial energy

Finite size effects influence simulation results

Hysteresis observed in curved surface adhesion

Abstract

The adhesive contact between elastic solids with randomly rough, self affine fractal surfaces is studied by molecular dynamics (MD) simulations. The interfacial binding energy obtained from the simulations of nominally flat and curved surfaces is compared with the predictions of the contact mechanics theory by Persson. Theoretical and simulation results agree rather well, and most of the differences observed can be attributed to finite size effects and to the long-range nature of the interaction between the atoms in the block and the substrate in the MD model, as compared to the analytical theory which is for an infinite system with interfacial contact interaction. For curved surfaces (JKR-type of problem) the effective interfacial energy exhibit a weak hysteresis which may be due to the influence of local irreversible detachment processes in the vicinity of the opening crack tip during pull-off.