Creep vs relaxation in disordered solids
| Quand ? |
Le 14/01/2027, de 11:00 à 12:00 |
|---|---|
| Où ? | TBD |
| S'adresser à | Giuseppe Petrillo |
| Participants |
Jérôme Weiss |
| Ajouter un événement au calendrier |
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Most solids, ranging from rocks, metals and alloys, concrete, paper, metallic glasses, to soft matter, when subjected to a constant load, slowly deform through creep. This deformation can accelerate over a finite time and lead to failure. However, under identical loading conditions, different samples exhibit extremely variable failure times, which raises the challenge of predicting them. Conversely, when held at a constant strain, these systems relax stress without leading to failure.
The phenomenology of creep and stress relaxation, that is, the time evolution of strains or stresses, has been known for a long time and exhibits a universal character. Yet, it remains relatively poorly understood from a theoretical perspective, even though thermal activation appears to play a crucial role due to the temperature dependence of creep.
In this presentation, we will address these questions through (i) experimental data on concrete and paper, (ii) theoretical analyses, and (iii) numerical models. We will show that empirical observations can be explained by a combination of quenched disorder, thermal activation, and stress redistribution. Based on this, we will also demonstrate how the time to failure is "encoded," at least partially, in the quenched disorder, and so can be predicted from the early activation times, as measured in the studied materials through acoustic emission.