Effects of poisson's ratio on the band gaps of three-dimensional solid/solid phononic crystals

Phononic crystals (PCs) are a kind of acoustic composite materials which have periodic structures and exhibit elastic wave (EW) band gaps. Due to their unique properties the phononic crystals have potential applications in acoustic devices and noise control, etc. The effects of both positive and negative Poisson's ratios on the phononic band gaps (PBGs) due to either Bragg scattering or locally resonance in three-dimensional (3D) solid/solid phononic crystals with a simple-cubic (SC) lattice are studied. The band structures are obtained by the finite difference time domain (FDTD) method combined with the fast Fourier transform- (FFT-) based postprocessing method. The numerical results show that Poisson's ratio of the scatterer plays an important role in tuning the PBGs.