0000000000585352
AUTHOR
Alan Geslain
Potentiel D’utilisation D’ondes Élastiques Guidées Pour La Caractérisation De Sandwichs Et De Multicouches Composites
International audience
Slatcow (Spatial Laplace Transform for Complex Wavenumber Recovery) Method for Frequency / Complex Wavenumber Dispersion Relation Recovery
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Acoustic characterization of Silica aerogel clamped plates for perfect absorption purpose
International audience; Silica aerogel has been widely studied as bulk material for its extremely low density and thermal conductivity. Plates or membranes made of this extremely soft materials exhibits interesting properties for sound absorption. A novel signal processing method for the characterization of an acoustic metamaterial made of silica aerogel clamped plates is presented. The acoustic impedance of a silica aerogel clamped plate is derived from the elastic theory for the flexural waves, while the transfer matrix method is used to model reflection and transmission coefficients of a single plate. Experimental results are obtained by using an acoustic impedance tube. The difference b…
Assessment of the Performance of Trim Materials : Modeling and Validation by Mean of Several Measurement Strategies
International audience; Trim materials are designed to minimize sound transmission and maximize sound absorption. Often, a balance between those two quantities is desired with an emphasis on one or another depending on the application in hand. Porous material are typically used as they allow for both sound absorption and transmission loss while minimizing the added mass. In this paper, the performance of a melamine foam panel is assessed. The considered sample is glued on the A2-size opening of a heavy concrete cabin designed for material testing in absorption (Alpha-cabin-like) and transmission (from the cabin to surrounding environment). The material is excited through a random sound fiel…
Caractérisation de nombres d'ondes complexes par transformée de Laplace : application aux ondes guidées dans les matériaux poreux
International audience
Assessment of the performance of trim materials: validation by mean of several measurement strategies
International audience; Trim materials are designed to minimize sound transmission and maximize sound absorption. Often, a bal-ance between those two quantities is desired with an emphasis on one or another depending on the application in hand. Porous material are typically used as they allow for both sound absorption and transmission loss while minimizing the added mass. In this paper, the performance of a melamine foam panel is assessed. The considered sample is glued on the A2-size opening of a heavy concrete cabin designed for material testing in absorption (Alpha-cabin-like) and transmission (from the cabin to surrounding environment). The material is excited through a random sound fie…
Recent developments in the acoustical properties of perforated and porous materials containing dead-end pores
It was shown recently in Nevers, France, Sherbrooke, Canada and Salford, UK, that porous materials with semi-opened pores or materials with open pores bearing lateral cavities or resonators at the microscopic scale of the pores can result in peculiar sound absorption properties. Various examples of these materials can be found in engineering and in everyday life including bio-based materials. The cavities and resonators can be assimilated to dead-end pores, which are opened at one end and closed at the other. The dead-end pores are known to geophysicists. We studied them more recently in the field of engineering acoustics where the saturating fluid is air. The closed ends prevent the fluid …
Propriétés acoustiques de matériaux perforés comprenant des pores dead-end périodiques pour des applications basses fréquences
International audience; Pour un matériau absorbant tel que la mélamine et pour une épaisseur assez faible (inférieure à 5 cm), l'absorption acoustique devient supérieure à 0.8 à partir d'une fréquence de l'ordre de 1000 Hz. Une étude récente [1] a montré que des matériaux perforés peu épais comportant le long des perforations des pores dead-ends (DE) régulièrement espacés peuvent permettre de produire des pics d'absorption supérieurs à 0.8 en basses fréquences (quelques centaines de Hz). Les dimensions des pores DE ainsi que leur périodicité peuvent être millimétrique ou submillimétrique de sorte que l'épaisseur totale du matériau soit de seulement quelques centimètres. Ces pores DE peuvent…
Etude Expérimentale des Modes de Lamb à Vitesse de Groupe Nulle (ZGV) dans le Plan Complexe des Nombres d'Ondes
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