Band structures of bilayer radial phononic crystal plate with crystal gliding

Lamb wave propagation in bilayer radial phononic crystal plate with crystal gliding is investigated. Axial symmetric model in cylindrical coordinate is applied to the bilayer radial phononic crystal plate for band structure calculation and transmission spectra. Gliding in radial direction and direction vertical to plate thickness is analyzed to modulate band gaps. Physical mechanism of gliding effects on radial phononic crystal plate is also studied with displacement fields of super cells. Numerical results show that crystal gliding both in radial direction and direction vertical to plate thickness can significantly tune omnidirectional band gaps. New lower band gaps occur and attenuation areas in transmission spectra are in good agreement with gaps of band structure calculation. Band structure evolution together with eigenmodes indicate that gliding effect converts lamb wave modes resulting in separations or interactions of adjacent bands to open new gaps or close the original ones. In addition, band gaps' sensitivity to crystal gliding is also investigated. Higher gaps are more sensitive to crystal gliding in thickness direction, and lowest gap extends in the map. Crystal gliding in radial direction can open new lowest order gap and open or close another two higher gaps, while the fourth gap is insensitive to it. The omnidirectional band gaps properties have potential application in acoustic device with isotropic gap characters. (C) 2014 AIP Publishing LLC.