Marko PopovićTom W. J. de GeusWencheng JiAlberto Rosso 1 Matthieu WyartTom W. J. de Geus
Marko Popović, Tom W. J. de Geus, Wencheng Ji, Alberto Rosso, Matthieu Wyart, et al.. Scaling Description of Creep Flow in Amorphous Solids. Physical Review Letters, 2022, 129 (20), pp.208001. ⟨10.1103/PhysRevLett.129.208001⟩. ⟨hal-03903994⟩
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.
- 1. LPTMS – Laboratoire de Physique Théorique et Modèles Statistiques