Measuring Spatial Distribution of Local Elastic Modulus in Glasses

TL;DR

This paper compares three methods for measuring local elastic moduli in glasses, highlighting differences caused by non-affine deformations and providing insights into spatial elastic heterogeneity.

Contribution

It systematically evaluates and compares three approaches for local elastic modulus measurement in glasses, emphasizing the effects of non-affine deformations.

Findings

The three methods yield different local elastic moduli due to non-affine effects.

The most recent low-cost method is easier to implement but shows some discrepancies.

Non-affine deformations significantly influence local elastic property measurements.

Abstract

Glasses exhibit spatially inhomogeneous elastic properties, which can be investigated by measuring their elastic moduli at a local scale. Various methods to evaluate the local elastic modulus have been proposed in the literature. A first possibility is to measure the local stress-local strain curve and to obtain the local elastic modulus from the slope of the curve, or equivalently to use a local fluctuation formula. Another possible route is to assume an affine strain and to use the applied global strain instead of the local strain for the calculation of the local modulus. Most recently a third technique has been introduced, which is easy to be implemented and has the advantage of low computational cost. In this contribution, we compare these three approaches by using the same model glass and reveal the differences among them caused by the non-affine deformations.