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DY: Fachverband Dynamik und Statistische Physik
DY 16: Statistical Physics 3 - organized by Barbara Drossel (Darmstadt), Sabine Klapp (Berlin) and Thomas Speck (Mainz)
DY 16.2: Talk
Monday, March 22, 2021, 16:50–17:10, DYb
Ageing and linear response in a mean field elastoplastic model — •Jack T. Parley1, Suzanne M. Fielding2, and Peter Sollich1,3 — 1Institut für Theoretische Physik, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Science Laboratories, Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom — 3Department of Mathematics, King’s College London, London WC2R 2LS, United Kingdom
Elastoplastic descriptions, based on the alternating elastic/plastic deformation of mesoscopic regions, provide key insights into the complex dynamics of athermal amorphous solids. These systems have recently also been found to display non-trivial ageing dynamics, driven by plastic events and the ensuing Eshelby (quadrupolar) stress redistribution. Here we construct a mean-field elastoplastic model for studying time-dependent perturbations and ageing dynamics, building on the work of Lin and Wyart (2016) for steady shear. Local stresses are driven by power-law distributed mechanical noise, characterised by the exponent µ. We study the ageing behaviour in the glassy regime, where the form of the yield rate decay varies for different values of the exponent µ, reflecting the relative importance of far-field and near-field events as the range of the stress propagator is varied. Moreover, a comparison of the mean-field predictions with ageing simulations of a lattice elastoplastic model shows excellent agreement. Finally, we obtain expressions for the linear stress response in the ageing regime, which will allow to test the theoretical predictions against stress measurements from experiments or simulations of model athermal systems.