Ventilated metamaterials for broadband sound insulation and tunable transmission at low frequency
DOI number:
10.1016/j.eml.2021.101348
Journal:
EXTREME MECHANICS LETTERS
Abstract:
Metamaterials enabling multifunctional wave control have long attracted great interest, but remain largely unexplored in ventilation-required settings. Using the space-coiling strategy, we design and fabricate a compact acoustic meta-structure consisting of labyrinth resonators arranged around a central air passage. Such meta-structures provide a promising route to design well-ventilated and simultaneously highly-effective sound-proofing barriers allowing broadband (about one octave band) transmission loss up to almost 30 dB in the range of 660-1200 Hz. More interestingly, due to the interferences between the forward propagating waves and those re-radiated by the surrounding resonators, some asymmetric Fano-like resonances are observed appearing in the transmission gap. This Fano-like resonance is very useful to open a high transmission window at frequencies of interest by changing the length of coiled-up channels. Our findings are both numerically and experimentally verified, which may stimulate multifunctional applications, such as broadband sound insulation with high transmission loss and tunable acoustic communication, especially in ventilation-required environments. (C) 2021 Elsevier Ltd. All rights reserved.
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