Avalanches and Structural Change in Cyclically Sheared Silica Glass

Abstract

We investigate avalanches associated with plastic rearrangements and the nature of structural change in the prototypical strong glass, silica, computationally. Although qualitative aspects of yielding in silica are similar to other glasses, we find that the statistics of avalanches exhibits non-trivial behaviour. Investigating the statistics of avalanches and clusters in detail, we propose and verify a new relation between exponents characterizing the size distribution of avalanches and clusters. Across the yielding transition, anomalous structural change and densification, associated with a suppression of tetrahedral order, is observed to accompany strain localisation.

Yielding behavior of glasses under asymmetric cyclic deformation

“…Recent years have witnessed significant activity in developing a statistical mechanical description of these phenomena [2][3][4][5]. Yielding behaviour in model amorphous solids has been investigated experimentally [6][7][8], through computer simulations [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], and theoretical investigations including the study of elastoplastic models and corresponding mean field theories [4,13,[27][28][29][30][31][32][33]. These investigations have largely focused on the response to uniform shear, but several investigations have explored yielding behaviour under cyclic deformation [11, 12, 19, 21, 23-26, 29, 31-35].…”

“…We perform AQS simulations of a three dimensional model glass former, the 80 : 20 Kob-Andersen binary Lennard-Jones mixture (KA-BMLJ), in which particles interact with a Lennard-Jones potential, employing a quadratic cutoff (with details provided in the Supplemental Material (SM) [47]). The results presented here were obtained from the simulations with system size N = 200 (25), 400 (15), 800 (15), 4000 (15), 8000(3), 32000(2), and 64000(1) particles, where the numbers in parentheses indicate the number of independent samples. With V being the sample volume, we equilibrate the system at fixed density ρ = N/V = 1.2 in the liquid state and at reduced temperatures T = 1.0, 0.60, 0.466, 0.40, 0.37 via a constant temperature molecular dynamics simulation.…”