Acoustic scattering reduction using layers of elastic materials. (3rd February 2017)

• Record Type: Journal Article
• Authors: Dutrion, Cécile; Simon, Frank
• Is Part Of: Journal of sound and vibration. Volume 388(2017)
• Page Start: 53
• Page End: 68
• Publication Date: 2017-02-03
• Subjects: Acoustic scattering -- Cylindrical shell -- Cloaking -- Optimization -- Elastic multilayer material; Sound -- Periodicals; Vibration -- Periodicals; Son -- Périodiques; Vibration -- Périodiques; Sound; Vibration; Periodicals; Electronic journals; 620.205
• DOI: 10.1016/j.jsv.2016.10.034
• Languages: English
• ISSNs: 0022-460X

Abstract

Abstract: Making an object invisible to acoustic waves could prove useful for military applications or measurements in confined space. Different passive methods have been proposed in recent years to avoid acoustic scattering from rigid obstacles. These techniques are exclusively based on acoustic phenomena, and use for instance multiple resonators or scatterers. This paper examines the possibility of designing an acoustic cloak using a bi-layer elastic cylindrical shell to eliminate the acoustic field scattered from a rigid cylinder hit by plane waves. This field depends on the dimensional and mechanical characteristics of the elastic layers. It is computed by a semi-analytical code modelling the vibrations of the coating under plane wave excitation. Optimization by genetic algorithm is performed to determine the characteristics of a bi-layer material minimizing the scattering. Considering an external fluid consisting of air, realistic configurations of elastic coatings emerge, composed of a thick internal orthotopic layer and a thin external isotropic layer. These coatings are shown to enable scattering reduction at a precise frequency or over a larger frequency band.