Increasing the modal density in plates for mono-element focusing in air

Acoustic focusing experiments usually require large arrays of transducers. It has been shown by Etaix et al. [J. Acoust. Soc. Am. 131, 395-399 (2012)] that the use of a cavity allows reducing this number of transducers. This paper presents experiments with Duralumin plates (the cavities) containing...

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Bibliographic Details
Published inThe Journal of the Acoustical Society of America Vol. 134; no. 2; p. 1049
Main Authors Etaix, Nicolas, Dubois, Jerôme, Fink, Mathias, Ing, Ros-Kiri
Format Journal Article
LanguageEnglish
Published United States 01.08.2013
Subjects
Acoustics - instrumentation
Air
Computer Simulation
Elasticity
Equipment Design
Fourier Analysis
Membranes, Artificial
Models, Theoretical
Motion
Numerical Analysis, Computer-Assisted
Scattering, Radiation
Sound
Sound Spectrography
Time Factors
Transducers
Vibration
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Summary:Acoustic focusing experiments usually require large arrays of transducers. It has been shown by Etaix et al. [J. Acoust. Soc. Am. 131, 395-399 (2012)] that the use of a cavity allows reducing this number of transducers. This paper presents experiments with Duralumin plates (the cavities) containing scatterers to improve the contrast of focusing. The use of a scatterer array in the plate allows increasing the modal density at given frequencies. The scatterers used are membranes and buttons that are manufactured in Duralumin plates. Their resonances are studied both experimentally and numerically. Such scatterers present the advantage of having a tunable frequency resonance, which allows controlling the frequencies at which the modal density increases. The dispersion relations of plates with scatterer array show high modal density at given frequencies. Finally acoustic focusing experiments in air, using these plates, are compared to the ones of simple duralumin plates demonstrating the improvement of contrast. Acoustic source localization is also realized using these plates.
ISSN:1520-8524
DOI:10.1121/1.4812260