Lecturer: Prof. Jay Fineberg (HUJI)
Abstract:
Recent experiments have demonstrated that rapid rupture fronts, akin to earthquakes,
mediate the transition to frictional motion. Moreover, once these dynamic rupture fronts
(“laboratory earthquakes”) are created, their singular form, dynamics and arrest are well-
described by fracture mechanics. Ruptures, however, need to be created within initially
rough frictional interfaces, before they are able to propagate. This is the reason that
“static friction coefficients” are not well-defined; frictional ruptures can nucleate for a wide
range of applied forces. A critical open question is, therefore, how the nucleation of
rupture fronts actually takes place. We experimentally demonstrate that rupture front
nucleation is prefaced by slow nucleation fronts. These nucleation fronts, which are self-
similar, are not described by our current understanding of fracture mechanics. The
nucleation fronts emerge from initially rough frictional interfaces at well-defined stress
thresholds, evolve at characteristic velocity and time scales governed by stress levels,
and propagate within a frictional interface to form the initial rupture from which fracture
mechanics take over. These results are of fundamental importance to questions ranging
from earthquake nucleation and prediction to processes governing material failure.
References
[1] Gvirtzman, S and Fineberg, J. , “Nucleation fronts ignite the interface rupture that
initiates frictional motion”, Nature Physics 17, 1037-1042 (2021).