Interplay between local frictional contact dynamics and global dynamics of a mechanical system

Friction affects almost the entirety of the mechanical systems in relative motion. In spite of intense and long-time research activities many aspects of this phenomenon still lack of a meaningful interpretation. Some of them could be explained by not focusing only on the interface properties. In fact recent literature confirms the picture of a macroscopic frictional behaviour of a mechanical system as the outcome of a complex interaction between the local dynamics at the frictional interface (wave and rupture nucleation and propagation) and the global dynamics of the system. This paper presents the results of a 2D non-linear finite element analysis under large transformations of the onset and evolution of sliding between two isotropic elastic bodies separated by a frictional interface. The aim is to investigate the trigger of the dynamic rupture at the interface, which preludes and goes with the sliding and its interaction with the global dynamics to determine the observed macroscopic frictional behaviour (stick-slip, continuous sliding). The analysis is focused on the observed phenomena during the onset of the sliding (micro-slips, precursors, macro-slips), accounting for the frictional properties and the inertial and elastic properties of the system.