Elastic Wave Band Structures and Defect States in a Periodically Corrugated Piezoelectric Plate

2014 ◽  
Vol 81 (8) ◽  
Author(s):  
Y. Huang ◽  
C. L. Zhang ◽  
W. Q. Chen

The band structures of shear horizontal (SH) waves in a periodically corrugated piezoelectric plate (PCPP) are studied by using the supercell plane wave expansion (SC-PWE) method. The effect of plate symmetry on the defect state caused by a defect in the plate is investigated in detail. The PCPPs with different types of symmetry give rise to different kinds of band gaps and the associated defect states. The increase of defect size lowers the frequency of defect bands, and it can be used to tune the narrow-passband frequencies in acoustic band gaps. Symmetry breaking is also introduced by reducing the lower corrugation depth of the PCPP. Results show that symmetry breaking leads to both the appearance and disappearance of new kinds of gaps and the corresponding defect bands in these gaps.

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550242
Author(s):  
Rongqiang Liu ◽  
Haojiang Zhao ◽  
Yingying Zhang ◽  
Honghwei Guo ◽  
Zongquan Deng

The plane wave expansion (PWE) method is used to calculate the band gaps of two-dimensional (2D) phononic crystals (PCs) with a hybrid square-like (HSL) lattice. Band structures of both XY-mode and Z-mode are calculated. Numerical results show that the band gaps between any two bands could be maximized by altering the radius ratio of the inclusions at different positions. By comparing with square lattice and bathroom lattice, the HSL lattice is more efficient in creating larger gaps.


2014 ◽  
Vol 81 (9) ◽  
Author(s):  
Y. Huang ◽  
C. L. Zhang ◽  
W. Q. Chen

The control of band structures of 2D phononic crystals (PCs) composed of piezoelectric inclusions and elastic isotropic matrix with mechanical/electrical biasing fields is theoretically investigated. The theory for small fields superposed on biasing fields and the plane wave expansion (PWE) method is employed to compute the band structures of the PCs under different biasing fields, including the initial shear/normal stress and the initial electric field. We find that the initial shear stress breaks the symmetry of the material. In consequence, the two bands associated with the level repulsion effect are opened near the apparent crosspoint and form a local band gap. On the other hand, the normal initial stress and the biasing electric field change the effective stiffness and shift the positions of band gaps. The observed phenomena show that the biasing fields can be flexibly used to tune the PC devices.


2021 ◽  
Author(s):  
Denghui Qian ◽  
Jianchun Wang ◽  
Feiyang He

Abstract The model of a locally resonant (LR) epoxy/PZT-4 phononic crystal (PC) nanobeam with “spring-mass” resonators periodically attached on epoxy is proposed. The corresponding band structures are calculated by coupling Euler beam theory, nonlocal piezoelectricity theory and plane wave expansion (PWE) method. Three complete band gaps with widest total width less than 10GHz can be formed in the proposed nanobeam by comprehensively comparing the band structures of three kinds of LR PC nanobeams with resonators attached or not. Furthermore, influencing rules of the coupling fields between electricity and mechanics, “spring-mass” resonator, nonlocal effect and different geometric parameters on first three band gaps are discussed and summarized. All the investigations are expected to be applied to realize the active control of vibration in the region of ultrahigh frequency.


2014 ◽  
Vol 597 ◽  
pp. 78-83 ◽  
Author(s):  
Hao Jiang Zhao ◽  
Rong Qiang Liu ◽  
Hong Wei Guo

Vibration band structures of thin phononic crystal plates (PCPs) with square array and graphite array of nitinol inserts are calculated by the plane wave expansion (PWE) method. The influences of filling fraction are considered when investigating the effects of the varying temperature on the band gaps. Vibration band gaps of these PCPs can be tuned by changing temperature. This study will be useful in designing PCPs with tunable gaps.


2014 ◽  
Vol 53 (9) ◽  
pp. 094301 ◽  
Author(s):  
Guang-huang Song ◽  
Jiu-jiu Chen ◽  
Xu Han

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