A hollow inclusion self-similarity phononic crystal with an ultra-low-frequency bandgap

FEA method is applied in order to investigate the bandgaps of two-dimensional (2D) phononic crystals which are composed with self-similarity hollow inclusions. Transmission spectra together with dispersion relations and displacement fields have been studied with FEA in detail. The simultaneous mechanisms of Bragg scattering enable multiterm bandgaps to be unfolded by the structure that can be effectively shifted by changing the lattice constant, matrix density and degree of self similarity. The smallest bandgap is located in the infrasonic wave range. Our results verify these phononic crystals with self-similar hollow inclusion structure which can change the number, location and width of bandgaps.