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DY: Fachverband Dynamik und Statistische Physik
DY 24: Complex Fluids and Soft Matter (joint session DY/CPP)
DY 24.11: Vortrag
Dienstag, 17. März 2020, 12:15–12:30, ZEU 160
Universal properties of creep flow — •Marko Popović1, Tom de Geus1, Wencheng Ji1, Alberto Rosso2, and Matthieu Wyart1 — 1Institue of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland — 2LPTMS, CNRS, Univ.Paris-Sud, Universite Paris-Saclay, 91405 Orsay, France
Amorphous solids, such as atomic glasses, colloidal suspensions, granular matter or foams, begin to deform plastically when exposed to external stress Σ. Steady state flow of these materials in absence of thermal fluctuations is usually described as є ∼ (Σ − Σc)β for stresses above critical stress Σc and vanishes below it, while in presence of thermal fluctuations flow persists below Σc but is exponentially suppressed. The transient plastic deformation, called creep flow, is much less understood despite its importance in practical applications. Creep flow often displays a power-law decay in time є∼ t−µ after which it can either arrest or eventually yield at fluidisation time τf. In recent years various numerical values and/or laws have been suggested for the exponent µ and time τf in particular experimental or numerical studies. We propose that mechanism underlying creep flow is the same as that of the steady state flow, which allows us to predicts parameters µ and τf of creep flow in terms of the steady state flow parameters, both in athermal and thermally activated systems. We successfully tested all our predictions using different mesoscopic elasto-plastic models of amorphous solids and found them to be consistent with published experimental results.