Thèse de doctorat en Mécanique, Energétique, Génie Civil et Acoustique
Sous la direction de Alain Le Bot.
Soutenue le 25-08-2015
à l'Ecully, Ecole centrale de Lyon en cotutelle avec l'Universitetet i Oslo , dans le cadre de Ecole Doctorale Mecanique, Energetique, Genie Civil, Acoustique (MEGA) (Villeurbanne) , en partenariat avec Laboratoire de tribologie et dynamique des systèmes (Écully, Rhône) (laboratoire) .
Friction is scientifically interesting and technologically important. We can characterize friction well, but even the friction force between macroscopic surfaces of known chemistry and topography under known loading conditions cannot yet be predicted from the bottom up. A major obstacle to predicting frictional properties is to link the macroscopic observations to the behavior of the myriad microscopic connections that make up the interaction.The onset of frictional sliding occurs through the breaking of the contacts that were keeping the interface stuck. Recent experiments performed with high spatial and temporal resolution show that rupture nucleates at weak or highly stressed points and propagates outwards from there. Understanding how the rupture travels is an important step towards understanding friction. This thesis presents simulations and theory aimed at improving our understanding of this onset of sliding in dry friction systems. The principal model combines 2D elasticity with an asperity level description of the interface and reproduces and explains many of the experimental results. Analytical calculations provide additional insights.