Crackling dynamics during the failure of heterogeneous materials — Quake catalogs at the laboratory scale

Speaker: Stéphane Santucci
The failure of heterogeneous materials is a complex process taking place on a verybroad range of scales: from the separation of atomic bonds, to the nucleation andgrowth of micro and macro voids, and even up to larger geological scales duringearthquakes and fault dynamics.During the seminar, we will discuss a model experimental set-up that allowed us toaccess and characterize in all details such a complex spatio-temporal dynamics, alsocalled “Crackling Noise”. Using both a high-resolution fast camera, and microphones, wecould track the slow growth of a crack front along a weak heterogeneous plane of aPlexiglas block, and show that the fracture front dynamics displays an intermittentbehavior driven by avalanches with very large size and velocity fluctuations. Such acrackling dynamics can be fully reproduced through a stochastic description derivedfrom Linear Elastic Fracture Mechanics and extended to weakly disordered materials. Inthis approach, quasi-static failure of heterogeneous brittle materials can be interpretedas a dynamic phase transition and as such, exhibits universal scaling behaviors.