Refractive Devices Based on Acoustic Metamaterials

2011 ◽  
Author(s):  
Rogelio Gracia´ ◽  
Daniel Torrent ◽  
Jose´ Sa´nchez-Dehesa
Keyword(s):  
Multiple Scattering ◽  
Numerical Experiments ◽  
Mass Density ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Dynamical Mass ◽  
Acoustic Waveguide ◽  
Refractive Lens ◽  
T Matrix

The t matrix of a hole in an acoustic waveguide is here obtained and applied to study the scattering of sound waves propagating inside a waveguide. It is found that a hole drilled in a waveguide behaves as a cylindrical unit whose dynamical mass density is lower than that of the surrounded background. This property has been used here to design an acoustic refractive lens. Numerical experiments based on multiple scattering simulations confirm the sound focusing by the designed device.

scholarly journals A Novel Approach to Density Near-Zero Acoustic Metamaterials

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Milan Sečujski ◽  
Norbert Cselyuszka ◽  
Vesna Crnojević-Bengin
Keyword(s):  
Acoustic Radiation ◽  
Mass Density ◽  
Phase Variation ◽  
Split Ring Resonator ◽  
Unit Cell ◽  
Effective Density ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Novel Approach ◽  
Acoustic Filters

The study demonstrates the possibility of achieving near-zero propagation of sound waves in acoustic metamaterials based on a membrane-based metamaterial unit cell which exhibits effective mass density of Lorentzian type. The unit cell, which represents the acoustic counterpart of the split ring resonator, was previously used as a building block of left-handed metamaterials, as it exhibits negative density at certain frequencies. In this study we show that its application can be extended to achieving propagation of sound waves at a frequency where its effective density equals zero. This effect can be exploited in a range of applications where extremely low phase variation over long physical distances is required, such as energy tunneling or tailoring the acoustic radiation phase pattern in arbitrary ways. After discussing the dependence of the frequency response of the unit cell on the properties of the host, we show that it can be used to design near-zero acoustic filters with low insertion loss and steep roll-off. Finally, we show that it can be used to achieve simultaneous near-zero propagation at multiple, independently chosen frequencies.

scholarly journals Bilayer ventilated labyrinthine metasurfaces with high sound absorption and tunable bandwidth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiayuan Du ◽  
Yuezhou Luo ◽  
Xinyu Zhao ◽  
Xiaodong Sun ◽  
Yanan Song ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Air Flow ◽  
Single Layer ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Sound Barrier ◽  
Free Air ◽  
Relative Bandwidth ◽  
Wide Range ◽  
High Sound

AbstractThe recent advent of acoustic metamaterials offers unprecedented opportunities for sound controlling in various occasions, whereas it remains a challenge to attain broadband high sound absorption and free air flow simultaneously. Here, we demonstrated, both theoretically and experimentally, that this problem can be overcome by using a bilayer ventilated labyrinthine metasurface. By altering the spacing between two constituent single-layer metasurfaces and adopting asymmetric losses in them, near-perfect (98.6%) absorption is achieved at resonant frequency for sound waves incident from the front. The relative bandwidth of absorption peak can be tuned in a wide range (from 12% to 80%) by adjusting the open area ratio of the structure. For sound waves from the back, the bilayer metasurface still serves as a sound barrier with low transmission. Our results present a strategy to realize high sound absorption and free air flow simultaneously, and could find applications in building acoustics and noise remediation.

Acoustic manipulation of fractal metamaterials with negative properties and near-zero densities

2021 ◽  
Author(s):  
Guanghua Wu ◽  
Yibo Ke ◽  
Lin Zhang ◽  
Meng Tao
Keyword(s):  
High Potential ◽  
Experimental Results ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Acoustic Device

Abstract Acoustic metamaterials have high potential in diverse applications, including acoustic cloaking, sound tunneling, wavefront reshaping, and sound insulation. In the present study, new metamaterials consisting of spatial coiled units are designed and fabricated to manipulate sound waves in the range 0-1600 Hz. The effective acoustic properties and band diagrams are studied. The simulation and experimental results demonstrate that the metamaterials provide an effective and feasible approach to design acoustic device such as sound cloaking and insulators.

Tunable acoustic waveguide based on vibro-acoustic metamaterials with shunted piezoelectric unit cells

2015 ◽  
Vol 24 (10) ◽  
pp. 105018 ◽  
Author(s):  
Byung-Jin Kwon ◽  
Jin-Young Jung ◽  
Dooho Lee ◽  
Kwang-Chun Park ◽  
Il-Kwon Oh
Keyword(s):  
Acoustic Metamaterials ◽  
Acoustic Waveguide ◽  
Unit Cells
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