Frequency-tunable sound insulation via a reconfigurable and ventilated acoustic metamaterial

Abstract

In acoustic engineering, sound-proofing ventilation barriers find wide applications in diverse situations. However, most of the structures only have responses with fixed frequencies and a very narrow frequency range, especially for low frequency acoustics. Here we show a subwavelength acoustic metamaterial based on labyrinthine structures, which possesses tunable sound insulation and ventilation properties. The Fano-like asymmetric transmission dips is formed by the interference between the resonant scattering of discrete states and the background scattering of continuous states. By adjusting the spacing between these two half zigzag molds, the sound insulation dip frequency can shift from 360 Hz to 575 Hz while the free ventilation area ratio is kept to over 36.3% and the total thickness is only about 0.06λ. Moreover, the noise peak frequency can be detected by a microphone detection and adaptive adjustment of the spacing with a small stepping motor is demonstrated, the results agree well with numerical simulations. We anticipate our design may find potential applications in acoustic air vents, soundproofing window and duct noise control.

Widely tunable magnetorheological metamaterials with nonlinear amplification mechanism

“…For wave and vibration control, the most important property of metamaterials is the possibility to generate bandgapsspecific frequency ranges, in which wave propagation is prohibited. The bandgap phenomenon has enabled to achieve remarkable wave filtering [14][15], waveguiding [16][17], vibration suppression [18][19], noise cancellation [20][21], impact mitigation [22][23], and other useful functionalities for wave manipulation.…”

Co-Design of Mechanical and Vibration Properties of a Star Polygon-Coupled Honeycomb Metamaterial

“…Metamaterials are artificial composite materials with a periodic arrangement of elements and remarkable physical properties that do not exist in natural materials. Welldesigned metamaterials exhibit excellent properties in many fields, such as mechanics [1][2][3][4], acoustics [5][6][7][8][9], optics [10][11][12][13], and electromagnetics [14][15][16]. Due to these special properties, metamaterials have been widely used in transportation [17,18], the automobile industry [19,20], aerospace [21,22], and other fields.…”

Study on Sound-Insulation Performance of an Acoustic Metamaterial of Air-Permeable Multiple-Parallel-Connection Folding Chambers by Acoustic Finite Element Simulation

“…This was pioneering of Ghaffarivardavagh et al, and provided effective guidance for the development of more practical sound insulators. Using this method, some novel acoustic metamaterials have been developed, such as a ventilated acoustic meta-barrier based on layered Helmholtz resonators [ 31 ], a three-dimensional reticular structure made with spheres [ 32 ], a ventilation barrier with space-coiling channels [ 33 ], a subwavelength acoustic metamaterial based on labyrinthine structures [ 34 ], an arch-like labyrinthine acoustic metasurface [ 35 ], a ventilated soundproof acoustic metamaterial consisting of resonant cavities arranged around a central air passage [ 36 ], nonlocal ventilating metasurfaces [ 37 ], etc. However, the shapes of these air-permeable acoustic metamaterials were complex, which meant that corresponding fabrications were difficult to realize and that their actual applications were limited.…”