Tunability of hysteresis-dependent band gaps in a two-dimensional magneto-elastic phononic crystal using magnetic and stress loadings

In this paper, the defect state and band gap characteristics in a two-dimensional slit structure phononic crystal, consisting of slotted steel tubes embedded in an air matrix, are investigated theoretically and experimentally. Using the finite element method and supercell technique, the dispersion relationships and power transmission spectra of the slit structures are calculated. The vibration modes of the band gap edges are analyzed to clarify the mechanism of the generation of the band gaps. Additionally, the influence of the slit width on the band gaps in slit structure is investigated. The slit width was found to influence the band gaps; this is critical to understand for practical applications. Based on this finding, a method to form defect scatterers by changing the slit width of a single central scatterer, or one row of scatterers, in the perfect PC was developed. Defect bands can be induced by creating defects inside the original complete band gaps. The frequency can then be tuned by changing the slit width of defect scatterers. Meanwhile, the relationship between point defect and line defect is investigated. Finally, we verify the results of theoretical research by experiments. These results will help in fabricating devices such as acoustic filters and waveguides whose band frequency can be modulated.

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Acoustic band gaps with diffraction gratings in a two-dimensional phononic crystal with a square lattice in water

Journal of the Korean Physical Society ◽

10.3938/jkps.68.989 ◽

2016 ◽

Vol 68 (8) ◽

pp. 989-993 ◽

Cited By ~ 1

Author(s):

Kang Il Lee ◽

Hwi Suk Kang ◽

Suk Wang Yoon

Keyword(s):

Phononic Crystal ◽

Diffraction Gratings ◽

Band Gaps ◽

Square Lattice ◽

Two Dimensional

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Influence of Point Defects on Band Gaps of Fe-Epoxy in Two-Dimensional Phononic Crystal

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.1377 ◽

2013 ◽

Vol 652-654 ◽

pp. 1377-1382

Author(s):

Jiao He ◽

Guang Hui Fan ◽

De Xun Zhao ◽

Ying Kai Liu

Keyword(s):

Point Defect ◽

Band Gap ◽

Nearest Neighbor ◽

Phononic Crystal ◽

Expansion Method ◽

Band Gaps ◽

Two Dimensional ◽

Defect States ◽

Filling Fraction ◽

Nearest Neighbor Coupling

The band gap of a new two-dimensional phononic crystal was studied by the plane-wave expansion method. The two-dimensional phononic crystal is formed by square-shape array geometry of iron cylinders with square cross section inserted in an epoxy resin. The band gaps of different structures were calculated such as defect-free, single cavity crystal point defect states, crystal point defect states with (10) direction coupling, crystal point defect states with (10) direction next-nearest-neighbor coupling, and crystal point defect states with (11) direction next-nearest-neighbor coupling. Compared with that of defect-free, it is conclude that point defect is beneficial to the production of band gaps. The bandwidth of point defect is about 5 times larger than that of the defect-free crystal with the filling fraction F=0.4. In addition, the maximum number of band gap is in the crystal point defect states with (10) direction next-nearest-neighbor coupling. It will provide a theoretical reference for the manufacture of phononic crystal.

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