One path to acoustic cloaking
Steven A. Cummer,David Schurig +1 more
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TLDR
In this paper, it was shown that the acoustic equations in a fluid are identical in form to the single polarization Maxwell equations via a variable exchange that also preserves boundary conditions, and the existence of transformation-type solutions for the 2D acoustic equations with anisotropic mass via time harmonic simulations of acoustic cloaking.Abstract:
A complete analysis of coordinate transformations in elastic media by Milton et al has shown that, in general, the equations of motion are not form invariant and thus do not admit transformation-type solutions of the type discovered by Pendry et al for electromagnetics. However, in a two-dimensional (2D) geometry, the acoustic equations in a fluid are identical in form to the single polarization Maxwell equations via a variable exchange that also preserves boundary conditions. We confirm the existence of transformation-type solutions for the 2D acoustic equations with anisotropic mass via time harmonic simulations of acoustic cloaking. We discuss the possibilities of experimentally demonstrating acoustic cloaking and analyse why this special equivalence of acoustics and electromagnetics occurs only in 2D.read more
Citations
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Experimental validation of a broadband pentamode elliptical-shaped cloak for underwater acoustics
Davide Enrico Quadrelli,Matteo Alessandro Casieri,Gabriele Cazzulani,Simone La Riviera,Francesco Braghin +4 more
TL;DR: In this article, a pentamode cloak with constant anisotropic elasticity and a scalar inhomogeneous density is proposed for scattering reduction of elliptical targets in underwater acoustics.
Journal ArticleDOI
Elastodynamic cloaking and field enhancement for soft spheres
Andre Diatta,Sébastien Guenneau +1 more
TL;DR: In this article, the authors proposed spherical cloaks described by a non-singular asymmetric elasticity tensor depending upon a small parameter that defines the softness of a region one would like to conceal from elastodynamic waves.
Journal ArticleDOI
Acoustic metamaterials with circular sector cavities and programmable densities.
W. Akl,Adel Elsabbagh,Amr M. Baz +2 more
TL;DR: The theoretical analysis of this class of multilayered composite active acoustic metamaterials (CAAMM) is presented and the theoretical predictions are determined for a cascading array of fluid cavities coupled to flexible piezoelectric active boundaries forming the meetamaterial domain with programmable dynamic density.
Journal ArticleDOI
Deterministic and probabilistic deep learning models for inverse design of broadband acoustic cloak
TL;DR: In this paper, a machine learning-driven acoustic cloak is proposed to suppress scattering of sound in a broad spectral range, as if it was not there, and an example of such a cloak with a multilayered core-shell configuration is demonstrated.
Journal ArticleDOI
The Gradient of Total Multiple Scattering Cross-Section and Its Application to Acoustic Cloaking
TL;DR: In this paper, the authors derived a formula for the gradients of the total scattering cross-section with respect to positions of a set of cylindrical scatterers, and derived the analytic form of the formula.
References
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Controlling Electromagnetic Fields
TL;DR: This work shows how electromagnetic fields can be redirected at will and proposes a design strategy that has relevance to exotic lens design and to the cloaking of objects from electromagnetic fields.
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Metamaterial Electromagnetic Cloak at Microwave Frequencies
David Schurig,Jack J. Mock,B.J. Justice,Steven A. Cummer,John B. Pendry,Anthony F. Starr,David R. Smith +6 more
TL;DR: This work describes here the first practical realization of a cloak of invisibility, constructed with the use of artificially structured metamaterials, designed for operation over a band of microwave frequencies.
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TL;DR: A general recipe for the design of media that create perfect invisibility within the accuracy of geometrical optics is developed, which can be applied to escape detection by other electromagnetic waves or sound.
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Ultrasonic metamaterials with negative modulus
Nicholas X. Fang,Dongjuan Xi,Jianyi Xu,Muralidhar Ambati,Werayut Srituravanich,Cheng Sun,Xiang Zhang +6 more
TL;DR: A new class of ultrasonic metamaterials consisting of an array of subwavelength Helmholtz resonators with designed acoustic inductance and capacitance with an effective dynamic modulus with negative values near the resonance frequency is reported.