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arXiv · 1803.06009

Diffusion in mesoscopic lattice models of amorphous plasticity

Botond Tyukodi·Craig E Maloney·Damien Vandembroucq
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Abstract

We present results on tagged particle diffusion in a meso-scale lattice model for sheared amorphous material in athermal quasi-static conditions. We find a short time diffusive regime and a long time diffusive regime whose diffusion coefficients depend on system size in dramatically different ways. At short time, we find that the diffusion coefficient, $D$, scales roughly linearly with system length, $D\sim L^{1.05}$. This short time behavior is consistent with particle-based simulations. The long-time diffusion coefficient scales like $D\sim L^{1.6}$, close to previous studies which found $D\sim L^{1.5}$. Furthermore, we show that the near-field details of the interaction kernel do not affect the short time behavior, but qualitatively and dramatically affect the long time behavior, potentially causing a saturation of the mean-squared displacement at long times. Our finding of a $D\sim L^{1.05}$ short time scaling resolves a long standing puzzle about the disagreement between the diffusion coefficient measured in particle-based models and meso-scale lattice models of amorphous plasticity.

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Botond Tyukodi, Craig E Maloney, Damien Vandembroucq. 2018-03-15. Diffusion in mesoscopic lattice models of amorphous plasticity. https://doi.org/10.1103/physrevlett.121.145501

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