Propagation of acoustic waves in 2D periodic and quasiperiodic phononic crystals

2017 ◽  
Vol 31 (21) ◽  
pp. 1750147 ◽  
Author(s):  
Arafa H. Aly ◽  
Ahmed Nagaty ◽  
Z. Khalifa
Keyword(s):  
Transmission Coefficient ◽  
Acoustic Waves ◽  
Stop Band ◽  
Fibonacci Sequence ◽  
Phononic Crystals ◽  
Solid Cylinder ◽  
Filling Fraction ◽  
Water Matrix ◽  
Aperiodic Structure ◽  
Sonic Waves

In this study, we have investigated theoretically the propagation of longitudinal sonic waves in 2D periodic and aperiodic (quasiperiodic) phononic crystals. Fibonacci sequence has been used to generate the aperiodic structure. The effect of transformation from 2D periodic to aperiodic structure has been elucidated by calculating the transmission coefficient. The consequences of inserting a circular solid cylinder inside a host water matrix have been repeated at the same calculating conditions. Changing filling fraction has been used to tune the stop band width.

Full Band-Gap Silicon Phononic Crystals for Surface Acoustic Waves

2006 ◽  
Author(s):  
Saeed Mohammadi ◽  
Abdelkrim Khelif ◽  
Ryan Westafer ◽  
Eric Massey ◽  
William D. Hunt ◽  
...  
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Surface Acoustic Waves ◽  
Hexagonal Lattice ◽  
Phononic Crystals ◽  
Bulk Wave ◽  
Filling Fraction ◽  
Phononic Band Gap ◽  
Wide Range

Periodic elastic structures, called phononic crystals, show interesting frequency domain characteristics that can greatly influence the performance of acoustic and ultrasonic devices for several applications. Phononic crystals are acoustic counterparts of the extensively-investigated photonic crystals that are made by varying material properties periodically. Here we demonstrate the existence of phononic band-gaps for surface acoustic waves (SAWs) in a half-space of two dimensional phononic crystals consisting of hexagonal (honeycomb) arrangement of air cylinders in a crystalline Silicon background with low filling fraction. A theoretical calculation of band structure for bulk wave using finite element method is also achieved and shows that there is no complete phononic band gap in the case of the low filling fraction. Fabrication of the holes in Silicon is done by optical lithography and deep Silicon dry etching. In the experimental characterization, we have used slanted finger interdigitated transducers deposited on a thin layer of Zinc oxide (sputtered on top of the phononic crystal structure to excite elastic surface waves in Silicon) to cover a wide range of frequencies. We believe this to be the first reported demonstration of phononic band-gap for SAWs in a hexagonal lattice phononic crystal at such a high frequency.

Multifunctional One-dimensional Phononic Crystal Structures Exploiting Interfacial Acoustic Waves

2009 ◽  
Vol 1188 ◽  
Author(s):  
Albert C To ◽  
Bong Jae Lee
Keyword(s):  
Acoustic Waves ◽  
Filter Design ◽  
Phononic Crystal ◽  
Stop Band ◽  
Phononic Crystals ◽  
Thermal Barrier ◽  
Interfacial Wave ◽  
Lateral Direction ◽  
One Dimensional ◽  
Wave Filter

AbstractThe present study demonstrates that interfacial acoustic waves can be excited at the interface between two phononic crystals. The interfacial wave existing between two phononic crystals is the counterpart of the surface electromagnetic wave existing between two photonic crystals. While past works on phononic crystals exploit the unique bandgap phenomenon in periodic structures, the present work employs the Bloch wave in the stop band to excite interfacial waves that propagate along the interface and decay away from the interface. As a result, the proposed structure can be used as a wave filter as well as a thermal barrier. In wave filter design, for instance, the incident mechanical wave energy can be guided by the interfacial wave to the lateral direction; thus, its propagation into the depth is inhibited. Similarly, in thermal barrier design, incident phonons can be coupled with the interfacial acoustic wave, and the heat will be localized and eventually dissipated at the interface between two phononic crystals. Consequently, the thermal conductivity in the direction normal to the layers can be greatly reduced. The advantage of using two phononic crystals is that the interfacial wave can be excited even at normal incidence, which is critical in many engineering applications. Since the proposed concept is based on a one-dimensional periodic structure, the analysis, design, and fabrication are relatively simple compared to other higher dimensional material designs.

Tunable Band Gaps of Acoustic Waves in Two-Dimensional Phononic Crystals With Reticular Band Structures

2009 ◽  
Author(s):  
Zi-Gui Huang ◽  
Yunn-Lin Hwang ◽  
Pei-Yu Wang ◽  
Yen-Chieh Mao
Keyword(s):  
Acoustic Waves ◽  
Composite Structures ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Sound Insulation ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Elastic Band ◽  
Band Structures ◽  
Elastic Band Gaps

The excellent applications and researches of so-called photonic crystals raise the exciting researches of phononic crystals. By the analogy between photon and phonon, repetitive composite structures that are made up of different elastic materials can also prevent elastic waves of some certain frequencies from passing by, i.e., the frequency band gap features also exist in acoustic waves. In this paper, we present the results of the tunable band gaps of acoustic waves in two-dimensional phononic crystals with reticular band structures using the finite element method. Band gaps variations of the bulk modes due to different thickness and angles of reticular band structures are calculated and discussed. The results show that the total elastic band gaps for mixed polarization modes can be enlarged or reduced by adjusting the orientation of the reticular band structures. The phenomena of band gaps of elastic or acoustic waves can potentially be utilized for vibration-free, high-precision mechanical systems, and sound insulation.

scholarly journals Моделирование проводимости Капицы через шероховатые интерфейсы между твердыми телами

2021 ◽  
Vol 63 (7) ◽  
pp. 982
Author(s):  
Б. Лю ◽  
В.И. Хвесюк ◽  
А.А. Баринов
Keyword(s):  
Experimental Data ◽  
Theoretical Prediction ◽  
Transmission Coefficient ◽  
Wide Temperature Range ◽  
Acoustic Waves ◽  
Theoretical Method ◽  
Interface Roughness ◽  
Kapitza Conductance ◽  
Acoustic Mismatch ◽  
The Difference

In this work, we have formulated and solved the problem of determining the Kapitza conductance across the interface between two solids, taking into account the interface roughness. We use a modified acoustic mismatch model (AMM). The difference from the classic model is that the dispersion properties of acoustic waves are considered. A significant advantage of this model is that the theoretical prediction agrees well with experimental data over a wide temperature range: from 30K to more than 300K. Finally, a theoretical method with the statistical distribution of roughness profiles is used to determine the energy transmission coefficient across the interface.

Surface Acoustic Waves in Phononic Crystals

2016 ◽  
pp. 145-189 ◽  
Author(s):  
Tsung-Tsong Wu ◽  
Jin-Chen Hsu ◽  
Jia-Hong Sun ◽  
Sarah Benchabane
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Phononic Crystals

scholarly journals Dual Photonic–Phononic Crystal Slot Nanobeam with Gradient Cavity for Liquid Sensing

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 421 ◽  
Author(s):  
Nan-Nong Huang ◽  
Yi-Cheng Chung ◽  
Hsiao-Ting Chiu ◽  
Jin-Chen Hsu ◽  
Yu-Feng Lin ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
The Finite Element Method ◽  
Concentrate Energy ◽  
Abrupt Changes ◽  
Analyte Solution ◽  
Liquid Sensing ◽  
Sensing Performance

A dual photonic–phononic crystal slot nanobeam with a gradient cavity for liquid sensing is proposed and analyzed using the finite-element method. Based on the photonic and phononic crystals with mode bandgaps, both optical and acoustic waves can be confined within the slot and holes to enhance interactions between sound/light and analyte solution. The incorporation of a gradient cavity can further concentrate energy in the cavity and reduce energy loss by avoiding abrupt changes in lattices. The newly designed sensor is aimed at determining both the refractive index and sound velocity of the analyte solution by utilizing optical and acoustic waves. The effect of the cavity gradient on the optical sensing performance of the nanobeam is thoroughly examined. By optimizing the design of the gradient cavity, the photonic–phononic sensor has significant sensing performances on the test of glucose solutions. The currently proposed device provides both optical and acoustic detections. The analyte can be cross-examined, which consequently will reduce the sample sensing uncertainty and increase the sensing precision.

scholarly journals Gradient index phononic crystals and metamaterials

Nanophotonics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 685-701 ◽  
Author(s):  
Yabin Jin ◽  
Bahram Djafari-Rouhani ◽  
Daniel Torrent
Keyword(s):  
Refractive Index ◽  
Wave Propagation ◽  
Acoustic Waves ◽  
Effective Properties ◽  
Periodic Structures ◽  
Phononic Crystals ◽  
Ray Theory ◽  
Acoustic Metamaterials ◽  
Propagation Of Waves ◽  
At Will

AbstractPhononic crystals and acoustic metamaterials are periodic structures whose effective properties can be tailored at will to achieve extreme control on wave propagation. Their refractive index is obtained from the homogenization of the infinite periodic system, but it is possible to locally change the properties of a finite crystal in such a way that it results in an effective gradient of the refractive index. In such case the propagation of waves can be accurately described by means of ray theory, and different refractive devices can be designed in the framework of wave propagation in inhomogeneous media. In this paper we review the different devices that have been studied for the control of both bulk and guided acoustic waves based on graded phononic crystals.

Angular control of acoustic waves oblique incidence by phononic crystals based on Dirac cones at the Brillouin zone boundary

2018 ◽  
Vol 382 (6) ◽  
pp. 423-427 ◽  
Author(s):  
Wen-Qiang Zhang ◽  
Xin Zhang ◽  
Fu-Gen Wu ◽  
Yuan-Wei Yao ◽  
Shui-Fang Lu ◽  
...  
Keyword(s):  
Brillouin Zone ◽  
Acoustic Waves ◽  
Oblique Incidence ◽  
Phononic Crystals ◽  
Zone Boundary ◽  
Brillouin Zone Boundary
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