Study on the low-frequency forbidden transmission properties of one-dimensional ternary solid-fluid sonic crystals by FEM

Abstract

Abstract Based on the finite element method (FEM), an acoustic transmission model of onedimensional ternary solid-fluid sonic crystals under the condition of oblique incidence is established. Transmission spectra of acoustic waves with different incident angles and frequencies in sonic crystals are calculated. The results show that two broadband forbidden band gaps exist in the low frequency range within two separated incident angle ranges for the ternary structure, which has one more band gap than the binary solid-fluid structure. By adjusting the solid filling fraction, period and lattice constant of the ternary structure, the angle widths of these two band gaps can be effectively regulated. This work will be of great significance to the design of underwater low-frequency acoustic filters.