Yielding in amorphous solids reveals an age-dependent intrinsic lengthscale

TL;DR

This paper uncovers an age-dependent intrinsic length scale in amorphous solids that governs local yielding, using a novel soft matrix method to better understand failure mechanisms and improve elastoplastic modeling.

Contribution

It introduces a new soft matrix approach to analyze local yielding, revealing an intrinsic length scale that grows with the system's age and influences stability.

Findings

The intrinsic length scale  grows with material age.

The distribution of local yield stress depends on age.

The pseudogap exponent  indicates marginal stability varies with age.

Abstract

Understanding how amorphous solids yield under shear is central to predicting material failure, yet prescribing reliable local yielding criteria remains a fundamental challenge. Here, through a mesoscale analysis of localized yielding, we reveal an intrinsic length scale (\zeta) that governs local failure, and demonstrate that \zeta grows with the age of the system. The age dependence shows up not only in the features of the distribution of local yield stress but also in the pseudogap exponent \theta, which provides a measure of marginal stability of the amorphous solids. These insights are made possible by a new method, termed the soft matrix approach, that allows local regions of an amorphous solid to yield within a minimally constrained, elastically coupled environment. By overcoming key limitations of earlier techniques, our approach provides a robust platform for probing failure mechanisms, particularly in soft disordered materials and paves the way for improved elastoplastic modeling of disordered solids.