scholarly journals Theoretical Optimization of Trapped-Bubble-Based Acoustic Metamaterial Performance

2020 ◽  
Vol 10 (16) ◽  
pp. 5720
Author(s):  
Dmitry Gritsenko ◽  
Roberto Paoli
Keyword(s):  
Low Frequency ◽  
Impedance Change ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Resonant Frequencies ◽  
Acoustic Metamaterial ◽  
Precise Control ◽  
Resonant Behavior ◽  
Versatile Tool ◽  
Analytical Expressions

Acoustic metamaterials have proven to be a versatile tool for the precise control and manipulation of sound waves. One of the promising designs of acoustic metamaterials employ the arrays of bubbles and find applications for soundproofing, blast mitigation, and many others. An obvious advantage of bubble-based metamaterials is their ability to be relatively thin while absorbing low-frequency sound waves. The vast majority of theories developed to predict resonant behavior of bubble-based metamaterials capitalize on Minnaert frequency. Here, we propose a novel theoretical approach to characterize bubble-based metamaterials that are based on our previous findings for a single bubble trapped in circular cavity modeled as a thin clamped plate. We obtain analytical expressions for resonant frequencies of bubble metascreens using self-consistent approximation. Two geometry factors, distance between bubble centers and distance between bubble center and interface of acoustic impedance change, are taken into account. We demonstrate the existence of multiple bandgaps and possibility of switching between them via adjustment of geometry parameters and reflector properties.

scholarly journals Hybrid acoustic metamaterial as super absorber for broadband low-frequency sound

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yufan Tang ◽  
Shuwei Ren ◽  
Han Meng ◽  
Fengxian Xin ◽  
Lixi Huang ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Functional Materials ◽  
Theoretical Method ◽  
Acoustic Metamaterials ◽  
Mechanical Stiffness ◽  
Acoustic Metamaterial ◽  
Frequency Sound

Abstract A hybrid acoustic metamaterial is proposed as a new class of sound absorber, which exhibits superior broadband low-frequency sound absorption as well as excellent mechanical stiffness/strength. Based on the honeycomb-corrugation hybrid core (H-C hybrid core), we introduce perforations on both top facesheet and corrugation, forming perforated honeycomb-corrugation hybrid (PHCH) to gain super broadband low-frequency sound absorption. Applying the theory of micro-perforated panel (MPP), we establish a theoretical method to calculate the sound absorption coefficient of this new kind of metamaterial. Perfect sound absorption is found at just a few hundreds hertz with two-octave 0.5 absorption bandwidth. To verify this model, a finite element model is developed to calculate the absorption coefficient and analyze the viscous-thermal energy dissipation. It is found that viscous energy dissipation at perforation regions dominates the total energy consumed. This new kind of acoustic metamaterials show promising engineering applications, which can serve as multiple functional materials with extraordinary low-frequency sound absorption, excellent stiffness/strength and impact energy absorption.

scholarly journals A Composite Perforated Partitioned Sandwich Panel With Corrugation for Underwater Low-Frequency Sound Absorption

2021 ◽  
Vol 7 ◽  
Author(s):  
Junyi Wang ◽  
Jiaming Hu ◽  
Yun Chen
Keyword(s):  
Acoustic Wave ◽  
Composite Structure ◽  
Sound Absorption ◽  
Low Frequency ◽  
Propagation Loss ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Underwater Sound ◽  
Underwater Acoustic ◽  
Frequency Sound

Underwater acoustic wave absorption and control play an important role in underwater applications. Various types of underwater acoustic metamaterials have been proposed in recent years with the vigorous development of acoustic metamaterials. Compared with airborne sound, underwater sound waves have a longer wavelength and much smaller propagation loss, making them more difficult to control. In addition, given that the acoustic impedance of water is much greater than that of air, numerous conventional materials and structures are not suited to underwater use. In this paper, we propose a composite structure based on an excellent broadband low-frequency sound absorber of air using aluminum mixed with rubber. Our composite structure possesses broadband low-frequency (<1,000 Hz) sound absorption underwater, omnidirectional high sound absorption coefficient under the oblique incidence (0–75°), and pressure resistance. It has promising applications for underwater acoustic wave control and contributes to the design of underwater acoustic metamaterials.

scholarly journals The Effect of Geometrical Parameters on Resonance Characteristics of Acoustic Metamaterials with Negative Effective Modulus

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao-Le Yan ◽  
Li-Mei Hao ◽  
Mei-Ling Men ◽  
Zhi Chen
Keyword(s):  
Resonance Frequency ◽  
Analytical Formula ◽  
Blue Shift ◽  
Theory Model ◽  
Outer Radius ◽  
Effective Modulus ◽  
Geometrical Parameters ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Acoustic Metamaterial

There has been an explosion of interest in acoustic metamaterial in the last ten years. The tunable negative acoustic metamaterial is an important issue for designing metamaterials. The acoustic metamaterial is restricted by the narrow bandgap of sound waves for the local resonance of metamaterial unit cells. By shifting the sizes of the unit cell, the acoustic metamaterial could potentially overcome the limit of the narrow resonance frequency. In this research, we focus on the resonant behavior of split hollow sphere (SHS) in the waveguide. Firstly, we analyze the resonance characteristics of SHS and get an analytical formula for the effect of geometrical parameters on the resonance frequency. Furthermore, the resonance frequency of SHS is verified with finite-element method analysis based on COMSOL Multiphysics simulation. The results are in good agreement with theory model. It is observed that there is a blue shift of the resonance frequency with the gradual increase of the neck radius of SHS, a V-type response curve with the increase of inner radius of SHS, and a red shift with the increase of outer radius of SHS. Using the method of estimate of resonance, we could get a precisely controllable unit structure with negative effective modulus and offer a way to optimize the realization of double negative acoustic metamaterial.

A membrane-type acoustic metamaterial muffler

2017 ◽  
Vol 31 (08) ◽  
pp. 1750049 ◽  
Author(s):  
Fang Wang ◽  
Tianning Chen ◽  
Xiaopeng Wang ◽  
Kai Bao ◽  
Lele Wan
Keyword(s):  
Transmission Loss ◽  
Low Frequency ◽  
Acoustic Metamaterials ◽  
Acoustic Transmission ◽  
Frequency Range ◽  
Transmission Performance ◽  
Acoustic Metamaterial ◽  
Dynamic Mass ◽  
Membrane Type ◽  
Theoretical Results

Membrane-type acoustic metamaterials (MAMs) with negative dynamic mass have demonstrated the effects in the sound transmission loss (STL) at low-frequency range. This research aims to design a membrane-type acoustic metamaterial muffler (MAMM) based on the present MAMs, and to solve the problem that airflow cannot flow unimpededly in the channel once using the MAMs. For a better understanding of MAMM, the resonance frequency of the membrane was calculated and simulation was used to study the acoustic transmission performance of the MAMM. The simulation results were verified in comparison with the theoretical results of the membrane. This MAMM reduced the structural size of muffler compared with the traditional Helmholtz muffler and expand muffler, which can find application for the MAMs in acoustic absorption and noise control.

scholarly journals Low-frequency perfect sound absorption achieved by a modulus-near-zero metamaterial

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chen Shao ◽  
Houyou Long ◽  
Ying Cheng ◽  
Xiaojun Liu
Keyword(s):  
Imaginary Part ◽  
Low Frequency ◽  
Destructive Interference ◽  
Perfect Absorber ◽  
Acoustic Metamaterials ◽  
Perfect Absorption ◽  
Acoustic Metamaterial ◽  
Dissipative Loss ◽  
Great Consistency ◽  
Practical Engineering

Abstract We have analytically proposed a mechanism for achieving a perfect absorber by a modulus-near-zero (MNZ) metamaterial with a properly decorated imaginary part, in which the perfect absorption (PA) is derived from the proved destructive interference. Based on the analysis, an ultrathin acoustic metamaterial supporting monopolar resonance at 157 Hz (with a wavelength about 28 times of the metamaterial thickness) has been devised to construct an absorber for low-frequency sound. The imaginary part of its effective modulus can be easily tuned by attentively controlling the dissipative loss to achieve PA. Moreover, we have also conducted the experimental measurement in impedance tube, and the result is of great consistency with that of analytical and simulated ones. Our work provides a feasible approach to realize PA (>99%) at low frequency with a deep-wavelength dimension which may promote acoustic metamaterials to practical engineering applications in noise control.

Performance of a Multifunctional Spiral Shaped Acoustic Metamaterial With Synchronized Low-Frequency Noise Filtering and Energy Harvesting Capability

2020 ◽  
Author(s):  
Fariha Mir ◽  
Sourav Banerjee
Keyword(s):  
Energy Harvesting ◽  
Electromagnetic Radiation ◽  
Smart Materials ◽  
Strain Energy ◽  
Low Frequency ◽  
Dual Function ◽  
Frequency Noise ◽  
Noise Filtering ◽  
Acoustic Metamaterials ◽  
Acoustic Metamaterial

Abstract Metamaterials are man-made materials that behave uniquely and possess exclusively desired properties that are not found in natural materials. Usually, it is the combination of two or more materials and can be engineered to perform tasks that are not possible with traditional materials. These were initially discovered while working with electromagnetic radiation. Apart from electromagnetic radiation, metamaterials are also capable of affecting the wave propagation characteristics through any fluid such as air. These metamaterials are called acoustic metamaterials. Many acoustic metamaterials have gone beyond its definition but still, characterize the waveguiding properties. Incorporation of smart materials while constructing acoustic metamaterial, can achieve multifunctionality of the design. A prospective application field for such acoustic metamaterials is energy harvesting from low-frequency vibration. It is conceptualized that acoustic metamaterials can be used as noise barrier materials to filter roadside and industrial noise. This application can get extended to the aerospace application where engine noise mitigation inside the cabin is a challenge. In this article, a spiral-shaped acoustic metamaterial is modeled which has a dual function of noise filtering and energy harvesting. This acoustic metamaterial has a comparatively high reflection coefficient closer to the anti-resonance frequencies, resulting in high sound transmission loss. The filtered noise is trapped inside the cell in the form of strain energy. Hence, we claim that if the trapped energy which is any way wasted in the material could be harvested to power the local electronic devices, the new solution could make transformative for the 21st century’s green energy solution. Calculated placement of smart materials in the cell-matrix can help to extract the strain energy in the form of power. The acoustic metamaterial cell presented in this work has the capability of isolating noise and reducing diffraction by trapping sound in low frequencies and at the same time recover the trapped abundant energy in the form of electrical potential using piezoelectric materials. The spiral design is sensitive to vibration due to trampoline shaped attachments inside the cell. This makes it capable of harvesting energy using vibration also. This is a promising acoustoelastic metamaterial with multifunctionality properties for future applications.

Simulation of Fabry-Perot Resonance for 3D Printable Complex Holey Acoustic Metamaterials

2020 ◽  
Author(s):  
Sanjay Ravichandran ◽  
Xin Wu ◽  
Yutai Su ◽  
Jing Shi
Keyword(s):  
Resonance Condition ◽  
Simulation Method ◽  
Complex Structures ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Frequency Range ◽  
Acoustic Metamaterial ◽  
Fabry Perot ◽  
Audible Frequency ◽  
Sub Wavelength

Abstract An acoustic metamaterial is a kind of material that is artificially designed in such a way that it can manipulate, control and direct sound waves. To date, various designs for acoustic metamaterials in the imaging applications have been proposed. However, these designs are generally simple due to the restriction from conventional manufacturing methods. By taking advantage of the additive manufacturing (AM) techniques, many complex acoustic metamaterials could be realized. However, the research on the complex structures for imaging applications has been very limited. In this paper, various 3D printable holey structured metamaterials with only one aperture are proposed, and the application possibility for sub-wavelength acoustic imaging in the audible frequency range is investigated. By using numerical simulation method, the effect of transmission properties of incident evanescent waves is analyzed to see whether these waves can completely transmit through the metamaterial. The phenomenon of Fabry-Perot resonances (FPR) that occur inside the hole for five different aperture shapes which are air-filled is studied, and the possibility of operating in a broadband resonance condition for the five designs are analyzed. These results can also be used to obtain valuable information for realizing a broadband acoustic hyperlens, which is an emerging application of 3D printable acoustic metamaterials.

Experimental Study of the Transmission Spectrum of a Sonic/Ultrasonic Acoustic Metamaterial

2016 ◽  
Author(s):  
Yanbo He ◽  
Jeffrey S. Vipperman
Keyword(s):  
Band Gap ◽  
Frequency Band ◽  
Transmission Spectrum ◽  
Physical Phenomenon ◽  
Experimental Studies ◽  
Low Frequency ◽  
Acoustic Metamaterials ◽  
Acoustic Metamaterial ◽  
Potential Applications ◽  
Lower Frequency Band

Acoustic metamaterials have received much attention recently. In the past decades, countless structures have been studied for their novel physical phenomenon or potential applications. The goals of many of the works were to explore ways to enlarge the band gap, lower the band gap frequency, and/or generate greater attenuation of vibration. However, most of the work was limited to simulation, with experimental studies rarer. In this work, we would like to experimentally present the transmission spectrum of an acoustic metamaterial with a proposed structure called the coated double hybrid lattice (CDHL) [1]. The CDHL has both crystalline structure and local resonators, which provide high-frequency and low-frequency band gaps, respectively. A structure was fabricated and tested to experimentally determine the transmission spectrum. Both, a higher frequency band gap and a lower frequency band gap, were obtained. Vibration is clearly attenuated in the frequency range of 70–90 kHz. This is due to the Bragg scattering effect. At the same time, around the frequency of 4.8kHz, another band gap is observed which is attributed to local resonance. It turns out that our experimental results coincide with our previous simulation quite well.

scholarly journals Study on broadband low-frequency sound insulation of multi-channel resonator acoustic metamaterials

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045321
Author(s):  
Chi Xu ◽  
Hui Guo ◽  
Yinghang Chen ◽  
Xiaori Dong ◽  
Hongling Ye ◽  
...  
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Acoustic Metamaterials ◽  
Frequency Sound

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.

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