Broadband asymmetric wave transmission in dissipative acoustic/elastic metamaterials with diatomic oscillators

Abstract

Asymmetric acoustic/elastic wave transmission have attracted increasingly attention recently. However, the propagation unidirectionality is always confined to a very narrow frequency band. This paper presents the development of a dissipative acoustic/elastic metamaterial with diatomic oscillators to realize “one-way” transmission in a broadband range. The effect of various types of dissipative oscillators on the asymmetric wave transmission is theoretically investigated and systematically discussed. By virtue of the surficial vibrational modes induced by the alternately arranged diatomic resonators and the merging effect of dissipative dashpot, the asymmetric transmission band is significantly broadened. Numerical results in frequency and time domains are verified using both lattice structures and continuum models. Preliminary experimental verification is further conducted. The broadband asymmetric transmission can be theoretically predicted and mathematically manipulated by careful design of the unit size parameters and deliberate selection of material properties, which could be potentially beneficial for applications in directional transducer and noise control.