title: Avalanches, precursors, and finite-size fluctuations in a mesoscopic model of amorphous plasticity.
abstract: We discuss avalanche and finite-size fluctuations in a mesoscopic model to describe the shear plasticity of amorphous materials. Plastic deformation is assumed to occur through series of local reorganizations. Yield stress criteria are random while each plastic slip event induces a quadrupolar long-range elastic stress redistribution. The model is discretized on a regular square lattice. Shear plasticity can be studied in this context as a depinning dynamic phase transition. We show evidence for a scale-free distribution of avalanches P(s) ∝ S(-κ) with a nontrivial exponent κ≈1.25 significantly different from the mean field result κ=1.5. Finite-size effects allow for a characterization of the scaling invariance of the yield stress fluctuations observed in small samples. We finally identify a population of precursors of plastic activity and characterize its spatial distribution.
authors.affiliation: Laboratoire PMMH, UMR 7636 CNRS/ESPCI/Université Paris 6 UPMC/Université Paris 7 Diderot, Paris, France.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Talamali
authors.forename: Viljo
authors.initials: V
authors.lastname: Petäjä
authors.forename: Damien
authors.initials: D
authors.lastname: Vandembroucq
authors.forename: Stéphane
authors.initials: S
authors.lastname: Roux
mesh_terms: D055595:Mechanical Phenomena; D008962:Models, Theoretical; D010969:Plastics; D013314:Stress, Mechanical
chemical_list: D010969:Plastics