Hierarchical models of engineering rough surfaces and bio-inspired adhesives

Friction, wear, adhesion and energy dissipation during sliding are strongly influenced by deformations of asperities, which, in turn, depend on the surface profile. At the nanoscale, the effects of surface roughness and the underlying physical phenomena, such as adhesion between contacting objects, have a considerable influence on the interaction between surfaces. Here various models of rough surfaces, including multi-level models, hierarchically structured models, and appropriate multi-scale models of contact interactions between rough surfaces are reviewed and discussed. A new model for numerical simulations of dry friction between rough engineering surfaces is introduced. The main features of the new model based on the use of a multi-level and multi-scale, hierarchically structured slider are described. Although the surface topography of the biological attachment devices is rather different from the topography of engineering surfaces, some existing models of bio-inspired adhesives are classified using terminology introduced for models of engineering rough surfaces