Metastability as a mechanism for yielding in amorphous solids under cyclic shear

Abstract

Considering a recently proposed model for the yielding of amorphous solids under cyclic shear deformation, we show that it can be analysed by mapping it, in the simplest case, to a random walk in a confining potential with an absorbing boundary. The dynamics is governed by the first passage time into the absorbing state, which captures the essential features of the original model, thereby providing insight into the observed robustness of earlier results. Including the possibility of activated escape from absorbing states leads to a unique determination of a threshold energy and yield strain, and further, suggests an appealing approach to understanding fatigue failure.

Avalanches and Structural Change in Cyclically Sheared Silica Glass

“…The response for large enough deformations involves plastic rearrangements, leading eventually to yielding. The yielding transition in amorphous solids has been investigated actively in recent years through experiments [4][5][6][7][8], numerical simulations [9][10][11][12][13][14][15][16][17][18][19] and theoretical investigations including analysis of elasto-plastic and other models [20][21][22][23][24][25][26][27][28][29][30]. Yielding has been observed to be a discontinuous transition for sufficiently well annealed glasses under uniform shear [17] and for cyclic shear [15,18,31], accompanied by a discontinuous drop in energy and stress, and by localisation of strain in shear bands [18,[32][33][34].…”