Spatial Distributions of Local Elastic Moduli Near the Jamming Transition

TL;DR

This study uses computer simulations to analyze how local elastic moduli in amorphous solids vary near the jamming transition, revealing Gaussian distributions, growing shear fluctuations, and a characteristic length scale.

Contribution

It introduces a linear response method to quantify elastic heterogeneities near jamming, highlighting a new power-law scaling of shear modulus fluctuations.

Findings

Local elastic moduli are spatially random and Gaussian distributed.

Shear modulus fluctuations diverge approaching the jamming point.

Identifies a length scale separating bulk and local elastic responses.

Abstract

Recent progress on studies of the nanoscale mechanical responses in disordered systems has highlighted a strong degree of heterogeneity in the elastic moduli. In this contribution, using computer simulations, we study the elastic heterogeneities in athermal amorphous solids, composed of isotropic, static, sphere packings, near the jamming transition. We employ techniques, based on linear response methods, that are amenable to experimentation. We find that the local elastic moduli are randomly distributed in space and are described by Gaussian probability distributions, thereby lacking any significant spatial correlations, that persists all the way down to the transition point. However, the shear modulus fluctuations grow as the jamming threshold is approached, which is characterized by a new power-law scaling. Through this diverging behavior we are able to identify a characteristic length scale, associated with shear modulus heterogeneities, that distinguishes between bulk and local elastic responses.