Abstract: Based on the local resonance and pipe silencing theories, an acoustic metamaterial structure with variable cross-section Helmholtz cavity was designed. The acoustic properties of the metamaterials were investigated by COMSOL simulation software. The effect of the geometric parameters of the acoustic metamaterial with variable cross-section on the coefficient peak was discussed, and the acoustic properties were determined by acoustic experiments. The results show that the acoustic structure with variable cross-section structure can realize satisfactory sound absorption effect in the low frequency range of 200-600 Hz. Changing the cross-sectional gradient of pipe holes can realize the directional adjustment of the natural frequency of acoustic structure. Compared with ordinary Helmholtz resonator, the sound absorption coefficient peak of the proposed acoustic structure can move within a certain low frequency range, and the sound absorption effect is improved in the low frequency range with widened frequency range corresponding to the sound absorption coefficient. The geometric parameters of the acoustic metamaterial structure are optimized with good sound absorption effect.
SHENG P, LIU Z, ZHANG X X, et al. Locally resonant sonic materials[J]. Physica B: Condensed Matter, 2003, 338:201-205.
[3]
FANG N, XI D J, XU J Y, et al. Ultrasonic metamaterials with negative modulus[J]. Nature Materials, DOI: 10.1038/nmat1644.
[4]
LEE S H, PARK C M, SEO Y M, et al. Composite acoustic medium with simultaneously negative density and modulus[J]. Physical Review Letters, DOI: 10.1103/PhysRevLett.104.054301.
[5]
CHERRIER O, POMMIER-BUDINGER V, SIMON F. Panel of resonators with variable resonance frequency for noise control[J]. Applied Acoustics, 2012,73(8):781-790.
ZHOU R, WU W G, WEN Y F. An acoustic metamaterial based on Helmholtz resonator with thin membrane[J]. Technical Acoustics,2017,36(4):297-302.(in Chinese)
[8]
MOSA A I, PUTRA A, RAMLAN R, et al. Theoretical model of absorption coefficient of an inhomogeneous MPP absorber with multi-cavity depths[J]. Applied Acoustics, 2019,146:409-419.
[9]
LI N, WANG Y Z, WANG Y S. Active control of elastic metamaterials consisting of symmetric double Helmholtz resonator cavities[J]. International Journal of Mechanical Sciences,DOI:10.1016/j.ijmecsci.2019.02.007.
[10]
HEDAYATI R, LAKSHMANAN S. Pneumatically-actuated acoustic metamaterials based on Helmholtz resonators[J]. Materials,DOI:10.3390/ma13061456.
WU W G,LIU C,BI J N. Double-layer membrane acoustic metamaterial with electromagnetic tunable frequency[J]. Journal of Jiangsu University(Natural Science Edition) ,2021,42(5):596-601.(in Chinese)
[12]
ZHANG X Q, LI C. Broadband and low frequency sound absorption by Sonic black holes with Micro-perforated boundaries[J]. Journal of Sound and Vibration, DOI: 10.1016/j.jsv.2021.116401.
[13]
GUO J W, ZHANG X, FANG Y, et al. An extremely-thin acoustic metasurface for low-frequency sound atte-nuation with a tunable absorption bandwidth[J]. International Journal of Mechanical Sciences, DOI: 10.1016/i.ijmecsci.2021.106872.
[14]
MA P S, KIM H S, LEE S H, et al. Quasi-perfect absorption of broadband low-frequency sound in a two-port system based on a micro-perforated panel resonator[J]. Applied Acoustics, DOI: 10.1016/j.apacoust.2021.108449.