Low-Frequency Band Gap of Novel Two-Dimensional Phonon Crystal and Its Formation Mechanism.

A new two-dimensional phonon crystal structure was designed and studied deeply by finite element method and equivalent model method. It is found that the structure has good low-frequency sound absorption performance. Through theoretical derivation and simulation calculation, it is found that the structure has a complete four band gap within 0 ~ 800 Hz under the condition of lattice constant of 21 mm. The lower limit of the first band gap is as low as 40. 28 Hz, and the bandwidth is approximately 93 Hz. Sound transmission loss calculation shows that the structure has a good acoustic insulation effect in the low frequency domain, and the maximum sound insulation amount can reach 87. 31 dB. After analyzing the multiple vibration modes of the structure, the corresponding equivalent model is established, and the influence of different factors on the band gap is explored based on the equivalent model. The general regularities of the new two-dimensional phonon crystal are summarized. The results show that increasing the scatterer density and reducing the matrix density can increase the bandwidth, and increasing the filling rate and properly opening the scatterer can improve the band gap characteristics. The research may provide some ideas for solving low-frequency noise control problems in engineering application. [ABSTRACT FROM AUTHOR]