Microscopic description of the intermittent dynamics driving logarithmic creep
Disordered materials under an imposed forcing can display creep and aging effects, accompanied by intermittent, spatially heterogeneous dynamics. We propose a unifying microscopic description of these phenomena, based on the notion that as the system ages, the density of local barriers that enable r...
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Main Authors | , , , |
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Format | Journal Article |
Language | English |
Published |
25.09.2024
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Subjects | |
Online Access | Get full text |
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Summary: | Disordered materials under an imposed forcing can display creep and aging
effects, accompanied by intermittent, spatially heterogeneous dynamics. We
propose a unifying microscopic description of these phenomena, based on the
notion that as the system ages, the density of local barriers that enable
relaxation displays a slowly evolving gap. As a result, the relaxation dynamics
is dominated by the activation of the lowest, extremal tail of the
distribution. This framework predicts logarithmic creep, as well as correlated
bursts of slow activated rearrangements, or 'thermal avalanches', whose size
grows logarithmically with their duration. The time interval between events
within avalanches obeys a universal power-law distribution, with a cut-off that
is simply proportional to the age of the system. We show that these predictions
hold both in numerical models of amorphous solids, as well as in experiments
with thin crumpled sheets. This analysis suggests that the heterogeneous
dynamics occurring during logarithmic creep is related to other phenomena,
including dynamical heterogeneities characterising the glass transition. |
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DOI: | 10.48550/arxiv.2409.17415 |