Underwater metamaterial absorber with impedance-matched composite
Qu, S.; Gao, N.; Tinel, A.; Morvan, B.; Romero-García, V.; Groby, J.-P.; Sheng, P. (2022). Underwater metamaterial absorber with impedance-matched composite. Science Advances 8(20). https://dx.doi.org/10.1126/sciadv.abm4206
In: Science Advances. AAAS: New York. ISSN 2375-2548; e-ISSN 2375-2548, more
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| Authors | | Top |
- Qu, S.
- Gao, N.
- Tinel, A.
- Morvan, B.
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- Romero-García, V.
- Groby, J.-P.
- Sheng, P.
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| Abstract |
By using a structured tungsten-polyurethane composite that is impedance matched to water while simultaneously having a much slower longitudinal sound speed, we have theoretically designed and experimentally realized an underwater acoustic absorber exhibiting high absorption from 4 to 20 kHz, measured in a 5.6 m by 3.6 m water pool with the time-domain approach. The broadband functionality is achieved by optimally engineering the distribution of the Fabry-Perot resonances, based on an integration scheme, to attain impedance matching over a broad frequency range. The average thickness of the integrated absorber, 8.9 mm, is in the deep subwavelength regime (~λ/42 at 4 kHz) and close to the causal minimum thickness of 8.2 mm that is evaluated from the simulated absorption spectrum. The structured composite represents a new type of acoustic metamaterials that has high acoustic energy density and promises broad underwater applications. |
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