Contact mechanics: contact area and interfacial separation from small contact to fullcontact

Abstract

We present a molecular dynamics study of the contact between a rigid solid with arandomly rough surface and an elastic block with a flat surface. The numerical calculationsmainly focus on the contact area and the interfacial separation from small contact (lowload) to full contact (high load). For a small load the contact area varies linearly with theload and the interfacial separation depends logarithmically on the load. For ahigh load the contact area approaches the nominal contact area (i.e. completecontact), and the interfacial separation approaches zero. The numerical resultshave been compared with analytical theory and experimental results. They are ingood agreement with each other. The present findings may be very important forsoft solids, e.g. rubber, or for very smooth surfaces, where complete contact canbe reached at moderately high loads without plastic deformation of the solids.