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

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.

Flexural Vibration Band Gaps in a Ternary Phononic Crystal Thin Plate

2011 ◽  
Vol 675-677 ◽  
pp. 1085-1088
Author(s):  
Zong Jian Yao ◽  
Gui Lan Yu ◽  
Jian Bao Li
Keyword(s):  
Band Gap ◽  
Thin Plate ◽  
Mass Density ◽  
Phononic Crystal ◽  
Flexural Vibration ◽  
Expansion Method ◽  
Band Gaps ◽  
Physical Parameters ◽  
Vibration Band ◽  
Filling Fraction

The band structures of flexural waves in a ternary locally resonant phononic crystal thin plate are studied using the improved plane wave expansion method. And the thin concrete plate composed of a square array of steel cylinders hemmed around by rubber is considered here. Absolute band gaps of flexural vibration with low frequency are shown. The calculation results show that the band gap width is strongly dependent on the filling fraction, the radius ratio, the mass density and the Young’s modulus contrasts between the core and the coating. So by changing these physical parameters, the required band gap could be obtained.

Frequency characteristics of defect states in a two-dimensional phononic crystal with slit structure

2016 ◽  
Vol 30 (06) ◽  
pp. 1650025 ◽  
Author(s):  
X. P. Wang ◽  
P. Jiang ◽  
T. N. Chen ◽  
K. P. Yu
Keyword(s):  
Band Gap ◽  
Power Transmission ◽  
Phononic Crystal ◽  
Slit Width ◽  
Band Gaps ◽  
Theoretical Research ◽  
Two Dimensional ◽  
Defect States ◽  
Band Frequency ◽  
Practical Applications

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.

Point defect states of a hollow cylinder in two-dimensional phononic crystal

2012 ◽  
Vol 21 (6) ◽  
pp. 064301 ◽  
Author(s):  
Xiao-Wei Gao ◽  
Shi-Bo Chen ◽  
Jian-Bing Chen ◽  
Qin-Hong Zheng ◽  
Hai Yang
Keyword(s):  
Point Defect ◽  
Hollow Cylinder ◽  
Phononic Crystal ◽  
Two Dimensional ◽  
Defect States

Band Gaps of Two-Dimensional Square-Lattice Photonic Crystal with Button-Shaped Dielectric Rods

2011 ◽  
Vol 216 ◽  
pp. 285-289
Author(s):  
S.X. Du ◽  
X. D. He ◽  
B. Liu ◽  
S. J. Li ◽  
Z.M. Zhang ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Plane Wave ◽  
Band Gap ◽  
Expansion Method ◽  
Band Gaps ◽  
Square Lattice ◽  
Two Dimensional ◽  
Plane Wave Expansion ◽  
Plane Wave Expansion Method ◽  
Wave Expansion

In this paper, a new structure of two-dimensional (2D) square-lattice photonic crystal (SLPC) with button-shaped dielectric rods (BSDRs) is designed, and the properties of band gaps are analyzed by Plane Wave Expansion Method (PWM). The optimal samples that possess the width of absolute band gap are obtained by scanning the three parameters: the radius of large circular R in button mark, the ratio of the radius of small circular to the radius of large circular r/R, and the rotating angle of button mark Ө. It is shown that when r/R=0.485, R=0.406um, and Ө =750, the largest absolute band gap of 0.0406 (ωa/2πc) exists for normalized frequencies in the range 0.7501 to 0.7910 (ωa/2πc). Besides，we can get at most five absolute band gaps when r/R=0.485, R=0.406um, and Ө =600.

Flexural Vibration in a Binary Phononic Crystal Thick Plate with a Point Defect

2010 ◽  
Vol 168-170 ◽  
pp. 1577-1580
Author(s):  
Zong Jian Yao ◽  
Gui Lan Yu ◽  
Yue Sheng Wang ◽  
Jian Bao Li
Keyword(s):  
Frequency Response ◽  
Point Defect ◽  
Band Gap ◽  
Response Function ◽  
Frequency Response Function ◽  
Thick Plate ◽  
Phononic Crystal ◽  
Flexural Vibration ◽  
Rubber Matrix ◽  
Filling Fraction

Based on the finite element method, the propagation of flexural vibration in a binary phononic crystal thick plate with a point defect is studied. The plate is composed of a square array of concrete cylinders embedded in the rubber matrix. Complete band structure and frequency response function of this perfect thick plate indicates the existence of low-frequency absolute band gap. Detailed investigations have been carried out to study the dependence of the width of absolute band gap on both structural and material parameters. For the point defect, the defect modes are localized around the defect, and the frequency and the number of the defect bands are significantly dependent on the filling fraction, the size and the mass density of the defect cylinder. To better support the statement of the defect band structures, we also represent the frequency response function of the propagation of flexural vibration in the thick plate with a point defect. Based on the detailed investigations, both the absolute band gap and the defect bands of a binary thick plate could be modulated with appropriate parameters. It may be useful to vibration control in engineering structure.

Effects of rotated square inserts on the longitudinal vibration band gaps in thin phononic crystal plates

2015 ◽  
Vol 29 (20) ◽  
pp. 1550105
Author(s):  
Haojiang Zhao ◽  
Rongqiang Liu ◽  
Chuang Shi ◽  
Hongwei Guo ◽  
Zongquan Deng
Keyword(s):  
Plane Wave ◽  
Longitudinal Vibration ◽  
Phononic Crystal ◽  
Expansion Method ◽  
Band Gaps ◽  
Vibration Band ◽  
Plane Wave Expansion ◽  
Plane Wave Expansion Method ◽  
Filling Fraction ◽  
Gap Width

Longitudinal vibration of thin phononic crystal plates with a hybrid square-like array of square inserts is investigated. The plane wave expansion method is used to calculate the vibration band structure of the plate. Numerical results show that rotated square inserts can open several vibration gaps, and the band structures are twisted because of the rotation of inserts. Filling fraction and material of the insert affect the change law of the gap width versus the rotation angles of square inserts.

Propagation of Lamb Waves in Phononic-Crystal Plates

2007 ◽  
Vol 23 (3) ◽  
pp. 223-228 ◽  
Author(s):  
J.-C. Hsu ◽  
T.-T. Wu
Keyword(s):  
Band Gap ◽  
Triangular Lattice ◽  
Lamb Waves ◽  
Phononic Crystal ◽  
Plate Thickness ◽  
Expansion Method ◽  
Band Gaps ◽  
Square Lattice ◽  
Pass Band ◽  
Band Structures

AbstractIn this paper, the band structures of Lamb waves in the two-dimensional phononic-crystal plates are calculated and analyzed based on the plane wave expansion method. The phononic-crystal plates are composed of an array of circular crystalline iron cylinders embedded in the epoxy matrix. Square lattice and triangular lattice are analyzed and discussed, respectively. For the square lattice, two complete band gaps exist, and a narrow pass band between the complete band gaps separates them apart. For the triangular lattice, a wide complete band gap existing with the ratio of gap width to midgap frequency Δω/ωm equal to 72% is found. Furthermore, the influence of the plate thickness is crucial for band structures of Lamb waves. Tuning plate thickness can shift the pass bands effectively, and band shifting causes the variation of the width of complete band gap and its opening and closure.

Influence of defect states on band gaps in the two-dimensional phononic crystal of 4340 steel in an epoxy

2012 ◽  
Vol 21 (9) ◽  
pp. 096101 ◽  
Author(s):  
Xiao-Yan Kong ◽  
Lei-Lei Yue ◽  
Yu Chen ◽  
Ying-Kai Liu
Keyword(s):  
Phononic Crystal ◽  
Band Gaps ◽  
Two Dimensional ◽  
Defect States ◽  
4340 Steel

scholarly journals Influence of defect states on band gaps of the 4340 steel in epoxy in two-dimensional phononic crystal

2011 ◽  
Vol 60 (10) ◽  
pp. 106103
Author(s):  
Yue Lei-Lei ◽  
Chen Yu ◽  
Fan Guang-Hui ◽  
He Jiao ◽  
Zhao De-Xun ◽  
...  
Keyword(s):  
Phononic Crystal ◽  
Band Gaps ◽  
Two Dimensional ◽  
Defect States ◽  
4340 Steel

Flexural Vibration in a Ternary Locally Resonant Phononic Crystal Thin Plate with Defects

2010 ◽  
Vol 150-151 ◽  
pp. 1282-1285
Author(s):  
Zong Jian Yao ◽  
Gui Lan Yu ◽  
Yue Sheng Wang ◽  
Jian Bao Li
Keyword(s):  
Point Defect ◽  
Thin Plate ◽  
Mass Density ◽  
Phononic Crystal ◽  
Flexural Vibration ◽  
Defect Mode ◽  
Expansion Method ◽  
Flexural Waves ◽  
Filling Fraction ◽  
Linear Defects

The improved supercell plane wave expansion method is applied to theoretically study the propagation of flexural waves in a ternary locally resonant phononic crystal thin plate with a point defect and linear defects. The thin concrete plate composed of a square array of steel cylinders hemmed around by rubber is considered here. Absolute band gaps in low frequency are obtained. For the point defect, the defect mode is localized around the defect, and the magnitude of the resonant defect mode is strongly dependent on the defect filling fraction, mass density and Young’s modulus of the defect cylinder. For the straight linear defects, several resonant linear defect bands appear inside the absolute band gap. And the displacement distributions show that the flexural waves could well propagate along the linear defects.

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