1905 Band gap characteristics of elastic waves in phononic crystals with thermal stress

2010 ◽  
Vol 2010.23 (0) ◽  
pp. 230-232
Author(s):  
Yi-Ze Wang ◽  
Feng-Ming Li ◽  
Kikuo Kishimoto
Keyword(s):  
Thermal Stress ◽  
Band Gap ◽  
Elastic Waves ◽  
Phononic Crystals ◽  
Gap Characteristics

Band gap characteristics of friction stir additive manufactured phononic crystals

2022 ◽  
Author(s):  
Z.J. Tan ◽  
Zhao Zhang
Keyword(s):  
Additive Manufacturing ◽  
Band Gap ◽  
Temperature Rise ◽  
Phononic Crystals ◽  
Inertia Moment ◽  
Welding Temperature ◽  
Rotating Speed ◽  
Friction Stir ◽  
Gap Characteristics ◽  
Lower Temperature

Abstract Additive Manufacturing (AM) is widely used to fabricate phononic crystals (PnCs) in recent years. Friction Stir Additive Manufacturing (FSAM) is a new-type solid state fabrication technology which is fusion free with low distortions. FSAM was selected to fabricate the designed PnCs. The manufactured specimen was distorted due to the temperature rise in the manufacturing process and the band gaps (BGs) were changed with the distortions. Results indicate that the band gap of the PnCs moves to be in higher frequency domain due to the residual distortions of the manufactured PnCs. The residual distortion of FSAM PnCs is 2.77 times smaller in comparison with the Tungsten Inert Gas (TIG) welding. So, the differences of the band gap between the designed PnCs and the FSAM specimen are only in the range of 0.15%- 0.55% due to the lower temperature rise in FSAM. The further analysis shows that the change of the BGs is caused by the growth of the inertia moment for the FSAM PnCs. With the increase of the rotating speed in FSAM, the residual distortion of the FSAM PnCs is increased due to the increase of the welding temperature. This can lead to the increase of the inertia moment, which is the key reason for the increase of the BG characteristics of the FSAM PnCs.

Quasi-One-Dimensional Periodic Structure with Locally Resonant Band Gap

2005 ◽  
Vol 73 (1) ◽  
pp. 167-170 ◽  
Author(s):  
Gang Wang ◽  
Xisen Wen ◽  
Jihong Wen ◽  
Yaozong Liu
Keyword(s):  
Band Gap ◽  
Periodic Structure ◽  
Elastic Waves ◽  
Phononic Crystals ◽  
Experimental Results ◽  
Harmonic Oscillators ◽  
Dimensional Structure ◽  
Stiffness Ratio ◽  
One Dimensional ◽  
Two Factors

The propagation of longitudinal elastic waves in quasi one-dimensional structure consisting of harmonic oscillators periodically jointed on a slender beam is studied. Sub-frequency locally resonant band gap with highly asymmetric attenuation is observed in both theoretical and experimental results, and both results match well. The stiffness and mass ratios are found analytically as two factors that influence the actual attenuation in the band gap of the locally resonant phononic crystals. The study on the weights of the two factors shows that the stiffness ratio is the key one. Thus, the reason for the mismatch between the regions of the sharp attenuation and the theoretical band gap in the locally resonant phononic crystals is discovered.

Band Gap Characteristics of Phononic Crystal Made from Different Material

2015 ◽  
Vol 723 ◽  
pp. 778-784 ◽  
Author(s):  
Xin Yan
Keyword(s):  
Band Gap ◽  
Theoretical Basis ◽  
Phononic Crystal ◽  
Wide Band ◽  
Phononic Crystals ◽  
Transmission Matrix ◽  
Wide Band Gap ◽  
One Dimensional ◽  
Gap Characteristics ◽  
Transmission Matrix Method

The band gap characteristics of phononic crystal is influenced by material and structure etc. Based on the transmission matrix method, the first band gap characteristics of one-dimensional phononic crystal were numerical simulation with different ratio, and these phononic crystals were made form aluminum, lead, steel, carbon and epoxy resin materials. These results show that phononic crystal structure made from high density materilal are more easier to form wide band gap, and there are also more easier to form wide band gap under the same proportion. These results provide theoretical basis for the design of one-dimensional phononic crystal devices.

Band Gap Properties of Piezoelectric/Viscous Liquid Phononic Crystals

2011 ◽  
Author(s):  
Yi-Ze Wang ◽  
Kazuaki Inaba ◽  
Feng-Ming Li ◽  
Kikuo Kishimoto
Keyword(s):  
Band Gap ◽  
Viscous Liquid ◽  
Phononic Crystals ◽  
Viscous Damping ◽  
Viscous Effects ◽  
Filling Fraction ◽  
Damping Parameter ◽  
Out Of Plane ◽  
Gap Characteristics ◽  
Gap Width

The viscous effects on the band gap characteristics of the piezoelectric/viscous liquid phononic crystals are studied. The expressions of the generalized eigenvalue equation for the cylindrical phononic crystals are derived. Numerical calculations are performed to discuss the band gap characteristics with different filling ratios and viscous damping parameters. Form the results, it can be observed that the out-of-plane mode will appear, which caused by the viscous effects. Both of the real and imaginary parts of frequencies will increase with the filling fraction becoming larger. The maximum of the normalized band gap width is achieved by f = 0.5. Furthermore, the band gap edges become higher with the viscous damping parameter increasing, especially for higher band gaps.

scholarly journals Research on the Band Gap Characteristics of Two-Dimensional Phononic Crystals Microcavity with Local Resonant Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Mao Liu ◽  
Pei Li ◽  
Yongteng Zhong ◽  
Jiawei Xiang
Keyword(s):  
Band Gap ◽  
Phononic Crystal ◽  
Engineering Application ◽  
Low Frequency ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Wave Band ◽  
Two Dimensional ◽  
Frequency Range ◽  
Gap Characteristics

A new two-dimensional locally resonant phononic crystal with microcavity structure is proposed. The acoustic wave band gap characteristics of this new structure are studied using finite element method. At the same time, the corresponding displacement eigenmodes of the band edges of the lowest band gap and the transmission spectrum are calculated. The results proved that phononic crystals with microcavity structure exhibited complete band gaps in low-frequency range. The eigenfrequency of the lower edge of the first gap is lower than no microcavity structure. However, for no microcavity structure type of quadrilateral phononic crystal plate, the second band gap disappeared and the frequency range of the first band gap is relatively narrow. The main reason for appearing low-frequency band gaps is that the proposed phononic crystal introduced the local resonant microcavity structure. This study provides a good support for engineering application such as low-frequency vibration attenuation and noise control.

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