Band gap characteristics of a new type of compound local resonance phononic crystal

In this paper, a new type of compound local resonance phononic crystal is designed, and the corresponding spring-mass equivalent model is established to calculate the upper and lower boundary frequencies of the band-gap. At the same time, the generation mechanism of the resonance band-gap is analyzed by the finite element method. The band-gap characteristics of the phononic crystal are studied according to the displacement modes at the start and end of the band-gap. The results show that the phononic crystal structure creates three complete band-gaps at a frequency of about 2 200 Hz, one of which is a broadband gap with a bandwidth of 406.17 Hz. The transmission characteristics of the phononic crystals with limited periodic structure are simulated and the sound insulation test is carried out, and the elastic wave propagation is hindered in the same frequency band. Finally, several factors affecting the band-gap of phononic crystal are analyzed, and how to regulate the upper and lower boundary of band-gap is discussed. The results provide a new idea and method for phononic crystal to obtain wide and low frequency band-gaps.