In this Note, infrared image sequences of a SiCf/SiC composite excited with a uniform heat pulse are processed using a modal approach. A new analytical integral transform (called analytical SVD or ASVD) inspired by the classical Singular Value Decomposition is developed and implemented on the raw experimental data. The second resulting spatial mode (out of a thousand) yielded by the ASVD provides, without further processing, a 2D mapping of the normalized local transverse diffusivity variations around a nominal value. Such mapping yields information on the inner structure of the material, and can be used to reveal the presence of voids inside the medium. This method is thus implemented on a tensile testing machine, to detect microcracks in a SiCf/SiC composite sample under mechanical stress in almost real time.
Dans cette étude, des séquences d'images infrarouges obtenues en filmant un composite SiCf/SiC excité par un flash uniforme sont traitées avec une approche modale. Une nouvelle transformation intégrale analytique (appelée SVD analytique ou ASVD) inspirée de la Décomposition en Valeurs Singulières classique est mise au point et appliquée aux données expérimentales brutes. Le deuxième mode spatial (parmi un millier) issu de l'ASVD fournit sans traitement supplémentaire une cartographie 2D normalisée des variations locales de diffusivités transverses autour d'une valeur nominale. De telles cartographies nous renseignent sur la structure interne du matériau, et peuvent être utilisées en particulier pour révéler la présence de cavités sous la surface. Cette méthode est donc implémentée sur un banc de traction, pour détecter en temps réel d'éventuelles microfissures sur un échantillon de composite SiCf/SiC soumis à une importante contrainte mécanique uniaxiale.
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Mots-clés : Transferts thermiques, Décomposition en Valeurs Singulières Analytique, Méthode flash, Camera infrarouge, Cartographie de diffusivités transverses, Composite céramique
Matthieu Bamford 1; Jean Christophe Batsale 1
@article{CRMECA_2008__336_5_440_0,
author = {Matthieu Bamford and Jean Christophe Batsale},
title = {Analytical {Singular} {Value} {Decomposition} of infrared image sequences: microcrack detection on ceramic composites under mechanical stresses},
journal = {Comptes Rendus. M\'ecanique},
pages = {440--447},
publisher = {Elsevier},
volume = {336},
number = {5},
year = {2008},
doi = {10.1016/j.crme.2007.12.003},
language = {en},
}
TY - JOUR AU - Matthieu Bamford AU - Jean Christophe Batsale TI - Analytical Singular Value Decomposition of infrared image sequences: microcrack detection on ceramic composites under mechanical stresses JO - Comptes Rendus. Mécanique PY - 2008 SP - 440 EP - 447 VL - 336 IS - 5 PB - Elsevier DO - 10.1016/j.crme.2007.12.003 LA - en ID - CRMECA_2008__336_5_440_0 ER -
%0 Journal Article %A Matthieu Bamford %A Jean Christophe Batsale %T Analytical Singular Value Decomposition of infrared image sequences: microcrack detection on ceramic composites under mechanical stresses %J Comptes Rendus. Mécanique %D 2008 %P 440-447 %V 336 %N 5 %I Elsevier %R 10.1016/j.crme.2007.12.003 %G en %F CRMECA_2008__336_5_440_0
Matthieu Bamford; Jean Christophe Batsale. Analytical Singular Value Decomposition of infrared image sequences: microcrack detection on ceramic composites under mechanical stresses. Comptes Rendus. Mécanique, Volume 336 (2008) no. 5, pp. 440-447. doi : 10.1016/j.crme.2007.12.003. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2007.12.003/
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