Mechanical excitation and marginal triggering during avalanches in sheared amorphous solids

Abstract

We study plastic strain during individual avalanches in overdamped particle-scale molecular dynamics (MD) and meso-scale elasto-plastic models (EPM) for amorphous solids sheared in the athermal quasi-static limit. We show that the spatial correlations in plastic activity exhibit a short lengthscale that grows as $t^{3/4}$ in MD and ballistically in EPM, and is generated by mechanical excitation of nearby sites not necessarily close to their stability thresholds, and a longer lengthscale that grows diffusively for both models and is associated with remote marginally stable sites. These similarities in spatial correlations explain why simple EPMs accurately capture the size distribution of avalanches observed in MD, though the temporal profiles and dynamical critical exponents are quite different.

References in corpus (7)

• Scaling description of the yielding transition in soft amorphous solids at zero temperature
• On the relevance of disorder in athermal amorphous materials under shear
• Inertia and universality of avalanche statistics: The case of slowly deformed amorphous solids
• Elastic consequences of a single plastic event: towards a realistic account of structural disorder and shear wave propagation in models of flowing amorphous solids
• Criticality in sheared, disordered solids. I. Rate effects in stress and diffusion
• Plastic response and correlations in athermally sheared amorphous solids
• Criticality in sheared, disordered solids. II. Correlations in avalanche dynamics

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