Avalanches and extreme value statistics in interfacial crackling dynamics

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences Vol. 377; no. 2136; p. 20170394
• Main Authors: Santucci, S, Tallakstad, K T, Angheluta, L, Laurson, L, Toussaint, R, Måløy, K J
• Format: Journal Article
• Language: English
• Published: England The Royal Society Publishing 14.01.2019
• Subjects: avalanches; extreme value statistics; depinning transition
• ISSN: 1364-503X; 1471-2962
• DOI: 10.1098/rsta.2017.0394

We study the avalanche and extreme statistics of the global velocity of a crack front, propagating slowly along a weak heterogeneous interface of a transparent polymethyl methacrylate block. The different loading conditions used (imposed constant velocity or creep relaxation) lead to a broad range of average crack front velocities. Our high-resolution and large dataset allows one to characterize in detail the observed intermittent crackling dynamics. We specifically measure the size , the duration , as well as the maximum amplitude [Formula: see text] of the global avalanches, defined as bursts in the interfacial crack global velocity time series. Those quantities characterizing the crackling dynamics follow robust power-law distributions, with scaling exponents in agreement with the values predicted and obtained in numerical simulations of the critical depinning of a long-range elastic string, slowly driven in a random medium. Nevertheless, our experimental results also set the limit of such model which cannot reproduce the power-law distribution of the maximum amplitudes of avalanches of a given duration reminiscent of the underlying fat-tail statistics of the local crack front velocities.This article is part of the theme issue 'Statistical physics of fracture and earthquakes'.