Coarse grained descriptions of the dynamics of yielding of amorphous solids under cyclic shear

TL;DR

This paper models the yielding transition in amorphous solids under cyclic shear by incorporating mechanical noise, revealing a dynamical transition that captures key features observed in simulations.

Contribution

It introduces a coarse-grained model with feedback mechanisms that successfully reproduces the dynamical transition associated with yielding.

Findings

Divergence of cycles to steady state near yielding point

Non-monotonic property changes with cycles

Spectrum of frozen states observed

Abstract

Recent computer simulations reveal several intriguing features in the evolution of properties of amorphous solids subjected to repeated cyclic shear deformation. These include the divergence of the number of cycles to reach steady states as the yielding point is approached, a non-monotonic change of properties with cycles, and the possibility of a spectrum of frozen states. Theoretical attempts to capture these properties through simple models, including the Ehrenfest model describing a random walk in a confining potential, have met partial success. Here, we show that incorporating the influence of mechanical noise through a feedback term leads to a genuine dynamical transition with characteristics reflecting those of yielding. Coarse graining the dynamics into a small number of variables leads to new insights regarding the dynamics of yielding.