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The duration-energy-size enigma for acoustic emission

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Peer-reviewed

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Authors

Casals, Blai 
Dahmen, Karin A. 
Gou, Boyuan 
Rooke, Spencer 
Salje, Ekhard K. H. 

Abstract

Abstract: Acoustic emission (AE) measurements of avalanches in different systems, such as domain movements in ferroics or the collapse of voids in porous materials, cannot be compared with model predictions without a detailed analysis of the AE process. In particular, most AE experiments scale the avalanche energy E, maximum amplitude Amax and duration D as E ~ Amaxx and Amax ~ Dχ with x = 2 and a poorly defined power law distribution for the duration. In contrast, simple mean field theory (MFT) predicts that x = 3 and χ = 2. The disagreement is due to details of the AE measurements: the initial acoustic strain signal of an avalanche is modified by the propagation of the acoustic wave, which is then measured by the detector. We demonstrate, by simple model simulations, that typical avalanches follow the observed AE results with x = 2 and ‘half-moon’ shapes for the cross-correlation. Furthermore, the size S of an avalanche does not always scale as the square of the maximum AE avalanche amplitude Amax as predicted by MFT but scales linearly S ~ Amax. We propose that the AE rise time reflects the atomistic avalanche time profile better than the duration of the AE signal.

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Keywords

Article, /639/301, /639/301/119, /639/301/119/996, /639/301/119/2795, article

Journal Title

Scientific Reports

Conference Name

Journal ISSN

2045-2322

Volume Title

11

Publisher

Nature Publishing Group UK
Sponsorship
Engineering and Physical Sciences Research Council (EP/P024904/1)
EU’s Horizon 2020 programme under the Marie Skłodowska-Curie grant agreement (861153)