Scaling description of creep flow in amorphous solids

Amorphous solids such as coffee foam, toothpaste or mayonnaise display a transient creep flow when a stress \(\Sigma\) is suddenly imposed. The associated strain rate is commonly found to decay in time as \(\dot{\gamma} \sim t^{-\nu}\), followed either by arrest or by a sudden fluidisation. Various...

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Bibliographic Details
Published in:arXiv.org 2022-10
Main Authors: Popović, Marko, Tom W J de Geus, Ji, Wencheng, Rosso, Alberto, Wyart, Matthieu
Format: Article
Language:English
Subjects:
Asymptotic properties
Elastoplasticity
Empirical analysis
Plastic flow
Strain rate
Toothpaste
Online Access:Get full text
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Summary:Amorphous solids such as coffee foam, toothpaste or mayonnaise display a transient creep flow when a stress \(\Sigma\) is suddenly imposed. The associated strain rate is commonly found to decay in time as \(\dot{\gamma} \sim t^{-\nu}\), followed either by arrest or by a sudden fluidisation. Various empirical laws have been suggested for the creep exponent \(\nu\) and fluidisation time \(\tau_f\) in experimental and numerical studies. Here, we postulate that plastic flow is governed by the difference between \(\Sigma\) and the transient yield stress \(\Sigma_t(\gamma)\) that characterises the stability of configurations visited by the system at strain \(\gamma\). Assuming the analyticity of \(\Sigma_t(\gamma)\) allows us to predict \(\nu\) and asymptotic behaviours of \(\tau_f\) in terms of properties of stationary flows. We test successfully our predictions using elastoplastic models and published experimental results.
ISSN:2331-8422
DOI:10.48550/arxiv.2111.04061