A lightweight yet sound-proof honeycomb acoustic metamaterial

Abstract

In this letter, a class of honeycomb acoustic metamaterial possessing lightweight and yet sound-proof properties is designed, theoretically proven, and then experimentally verified. It is here reported that the proposed metamaterial having a remarkably small mass per unit area at 1.3 kg/m2 can achieve low frequency (<500 Hz) sound transmission loss (STL) consistently greater than 45 dB. Furthermore, the sandwich panel which incorporates the honeycomb metamaterial as the core material yields a STL that is consistently greater than 50 dB at low frequencies. The proposed metamaterial is promising for constructing structures that are simultaneously strong, lightweight, and sound-proof.

A novel broadband waterborne acoustic absorber

“…Generally, the viscosity of the host material, the resonance mode, and the gradient impedance of the material are three important factors for the improvement of sound absorption process in layer materials. For resonance layer, [2][3][4] both viscoelastic material and resonance mode 5 are employed. For instance, Alberich anechoic coating, which is the rubber layer with cavities in a doubly periodic lattice, was first used in the Second World War due to its excellent echo reduction properties.…”

Comment on “A lightweight yet sound-proof honeycomb acoustic metamaterial” [Appl. Phys. Lett. 106, 171905 (2015)]

“…Phys. Lett In the recent letter, Sui et al 1 claim that they created and tested sandwich material with a transmission loss (TL) of 35-55 dB ( Figure 3) and 55 dB in (Figure 4) at a frequency of f ¼ 200 Hz. Both sandwich constructions are tested in an impedance tube test bench as described by Song and Bolton.…”

Omnidirectional ventilated acoustic barrier

“…Yet the passive methods generally have to rely on impedance mismatch by insertion of layered materials, which would be bulky in terms of wavelength if realized with natural materials [1]. Although the advance of metamaterials [10][11][12][13][14][15][16][17][18][19][20][21] has overcome the problem of limited acoustical properties available in nature and enabled substantial reduction in both the thickness and mass density of sound-proof structures such as by using membrane-type metamaterials [3][4][5][6], there is still a fundamental limit that the inserted natural or artificial materials necessarily lead to discontinuity of the surrounding air, making them not practical in environments in need of ventilation. Despite the recent emergence of open structures for sound insulation, they need to decorate the inner boundaries of a waveguide with 3 metasurfaces [14][15][16][19][20][21] for generating anomalous reflection and therefore have to be bulky-sized, angular-dependent and inapplicable to free space [7].…”

“…Conventionally, sound insulation can be realized by both active [8][9] and passive methods [3][4][5][6][7]. Compared with active methods that need complicated and costly electronic systems, the use of passive structures provide simple solutions much easier to apply in practice.…”

“…As an important problem in acoustics, sound insulation [1][2][3][4][5][6][7][8][9] finds wide applications in diverse scenarios ranging from noise control to architectural acoustics.…”