A Green’s Function Molecular Dynamics Approach to the Mechanical Contact between Thin Elastic Sheets and Randomly Rough Surfaces

Adhesion of biological systems is often made possible through thin elastic layers, such as human skin. To address the question of when a layer is sufficiently thin to become adhesive, we extended Green's function molecular dynamics (GFMD) to account for the finite thickness of an elastic body that is supported by a fluid foundation. We observed that thin layers can much better accommodate rough counterfaces than thick structures. As a result, the contact area is enlarged, in particular, when the width of the layer omega approaches or even falls below the short-wavelength cutoff lambda(s) of the surface spectra. In the latter case, the proportionality coefficient between area and load scales is ( w/lambda(s))(3), which is consistent with Persson's contact mechanics theory.