Solid-on-solid single block dynamics under mechanical vibration

The suppression of friction between sliding objects, modulated or enhanced by mechanical vibrations, is well established. However, the precise conditions of occurrence of these phenomena is not well understood. Here we address these questions focusing on a simple spring--block model, which is relevant to investigate friction both at the atomistic as well as the macroscopic scale. This allows to investigate the influence on friction of the properties of the external drive, of the geometry of the surfaces over which the block moves, and of the confining force. Via numerical simulations and a theoretical study of the equations of motion we identify the conditions under which friction is suppressed and/or recovered, and evidence the critical role played by surface modulations and by the properties of the confining force.