Low frequency sound absorption of adjustable membrane-type acoustic metamaterials

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.

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

Frontiers in Mechanical Engineering ◽

10.3389/fmech.2021.679656 ◽

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.

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Progress of low-frequency sound absorption research utilizing intelligent materials and acoustic metamaterials

RSC Advances ◽

10.1039/d1ra06493b ◽

2021 ◽

Vol 11 (60) ◽

pp. 37784-37800

Author(s):

Longfei Chang ◽

Ajuan Jiang ◽

Manting Rao ◽

Fuyin Ma ◽

Haibo Huang ◽

...

Keyword(s):

Sound Absorption ◽

Low Frequency ◽

Acoustic Metamaterials ◽

Intelligent Materials ◽

Frequency Sound

In this review, the latest progress of intelligent materials incorporated with acoustic metamaterials is summarized to provide an impetus for this highly interdisciplinary advancement towards low-frequency sound absorption.

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Spider Web-Inspired Lightweight Membrane-Type Acoustic Metamaterials for Broadband Low-Frequency Sound Isolation

Polymers ◽

10.3390/polym13071146 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1146

Author(s):

Heyuan Huang ◽

Ertai Cao ◽

Meiying Zhao ◽

Sagr Alamri ◽

Bing Li

Keyword(s):

Reference Model ◽

Low Frequency ◽

Sound Attenuation ◽

Polymeric Membrane ◽

Acoustic Metamaterials ◽

Frequency Range ◽

Spider Web ◽

Frequency Sound ◽

Resonance Modes ◽

Membrane Type

Membrane-type acoustic metamaterial (MAM) has exhibited superior sound isolation properties, as well as thin and light characteristics. However, the anti-resonance modes of traditional MAMs are generated intermittently in a wide frequency range causing discontinuities in the anti-resonance modes. Achieving broadband low-frequency sound attenuation with lightweight MAM design is still a pivotal research aspect. Here, we present a strategy to realize wide sound-attenuation bands in low frequency range by introducing the design concept of bionic configuration philosophy into the MAM structures. Built by a polymeric membrane and a set of resonators, two kinds of MAM models are proposed based on the insight of a spider web topology. The sound attenuation performance and physical mechanisms are numerically and experimentally investigated. Multi-state anti-resonance modes, induced by the coupling of the bio-inspired arrangement and the host polymer film, are systematically explored. Significant sound attenuation is numerically and experimentally observed in both the lightweight bio-inspired designs. Remarkably, compared with a traditional MAM configuration, a prominent enhancement in both attenuation bandwidth and weight-reduction performance is verified. In particular, the bio-inspired MAM Model I exhibits a similar isolation performance as the reference model, but the weight is reduced by nearly half. The bio-inspired Model II broadens the sound attenuation bandwidth greatly; meanwhile, it retains a lighter weight design. The proposed bio-inspired strategies provide potential ways for designing sound isolation devices with both high functional and lightweight performance.

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Research on Low Frequency Sound Insulation Properties of Membrane-Type Acoustic Metamaterials

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1210/1/012001 ◽

2021 ◽

Vol 1210 (1) ◽

pp. 012001

Author(s):

Xiaokai Yin ◽

Yongchao Xu ◽

Hongyu Cui

Keyword(s):

Noise Control ◽

Low Frequency ◽

Sound Insulation ◽

Frequency Noise ◽

Acoustic Metamaterials ◽

Frequency Sound ◽

Field Coupling ◽

Cabin Noise ◽

Sound Structure ◽

Membrane Type

Abstract To solve the problem of low-frequency noise control in ship cabins, a new membrane-type acoustic metamaterial (MAM) with bulges on the surface of thin films is designed based on the characteristics of lightweight and low-frequency sound insulation of membrane-type acoustic metamaterials. The sound structure coupling module of COMSOL multiphysical field coupling software is used to analyse the sound insulation performance of MAMs. The sound insulation properties of the additional mass film and self-similar fractal convex structure are further discussed. The metamaterial structure studied in this paper has a better sound insulation effect than ordinary film, which provides strong technical support for ship cabin noise control.

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