Spatiotemporal analysis of nonaffine displacements in disordered solids sheared across the yielding point

TL;DR

This study uses molecular dynamics simulations to analyze how nonaffine displacements evolve and correlate spatially in amorphous solids under shear, revealing a transition from homogeneous clusters to localized shear bands at yielding.

Contribution

It provides new insights into the spatial and temporal behavior of nonaffine displacements during yielding in disordered solids, highlighting the transition in correlation decay and cluster size.

Findings

Cluster size of nonaffine displacements increases with strain

Spatial correlation shifts from exponential to power-law at yielding

Pair correlation function peak height increases at yielding

Abstract

The time evolution and spatial correlations of nonaffine displacements in deformed amorphous solids are investigated using molecular dynamics simulations. The three-dimensional model glass is represented via the binary mixture, which is slowly annealed well below the glass transition temperature and then sheared at a constant strain rate. It is shown that with increasing strain, the typical size of clusters of atoms with large nonaffine displacements increases, and these clusters remain spatially homogeneously distributed, until the yielding point when mobile atoms become localized within a system-spanning shear band. Furthermore, the yielding transition is associated with an abrupt change in the spatial correlation of nonaffine displacements, which varies from exponential to power-law decay. We also find that the height of the first peak in the pair correlation function of small atoms exhibits a distinct increase at the yielding strain. These results are discussed in relation to the yielding transition in amorphous materials under cyclic loading.