Acoustic band gaps in one-dimensional Helmholtz resonator metamaterials with disperiodical defects

• Published in: The Journal of the Acoustical Society of America 2012-04, Vol.131 (4_Supplement), p.3327-3327
• Main Authors: Gao, Dongbao, Zeng, Xinwu
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4708450

The metamaterials containing Helmholtz resonators (HR) can exhibit two kinds of forbidden gaps. The dynamic density and effective bulk modulus are simultaneously negative in the gap of local-resonant-type. It is considered to be one of the possible materials to implement a lot of applications based on transformation acoustics. Acoustic transmission properties of one-dimensional metamaterials with periodically and disperiodically distributed HRs are calculated based on acoustic transmission line method (ATLM). The relationship between the transmission coefficient and HR parameters is analyzed. The band gaps of 1D HR metamaterials with periodical defects are also investigated. The Bragg-scattering-type gaps exist at the frequencies associated with the effective periodic constant. The defect modes are observed in the gaps of local-resonant-type. Furthermore, another metamterial with gradually changed HRs is also researched as a disperiodical type. This work enriched the studies of HR metamaterials, which can be helpful for realizing new filters and cloaks.