Bandgap Structures of SH-Wave in a One-Dimensional Phononic Crystal with Viscoelastic Interfaces

2017 ◽  
Vol 09 (07) ◽  
pp. 1750102 ◽  
Author(s):  
Yuhang Li ◽  
Xiaoliang Zhou ◽  
Zuguang Bian ◽  
Yufeng Xing ◽  
Jizhou Song
Keyword(s):  
Periodic Structure ◽  
Phononic Crystal ◽  
Adhesive Layer ◽  
Phononic Crystals ◽  
Sh Wave ◽  
Initial State ◽  
Final State ◽  
One Dimensional ◽  
Adhesive Layers ◽  
And Control

Phononic crystal is an artificial periodic structure with the ability to regulate and control the wave propagation of particular frequencies and has been widely used in many applications. The adhesive layer bonding different constituents in the periodic structure of phononic crystals is usually a viscoelastic material, which has frequency-dependent material properties. In this paper, an analytical model based on the transfer matrix method is developed to study the bandgap structures of SH-wave (a shear wave with the propagation direction normal to the motion plane) in a one-dimensional phononic crystal consisting of two different elastic constituents bonded by the viscoelastic adhesive layer. The results show that the viscosity of the adhesive layer has a significant influence on the bandgap structure at the region of high frequency. The effects of various material parameters of the viscoelastic adhesive layer such as the relaxation time, the final-state modulus and the initial-state modulus are systematically studied. These results are very helpful in the practical design of phononic crystals involving the viscoelastic adhesive layers.

Acoustic wave frequency filtering in constant total length phononic crystals of Al/Pb multilayer

2021 ◽  
Author(s):  
Chittaranjan Nayak ◽  
Mehdi Solaimani ◽  
Alireza Aghajamali ◽  
Arafa H. Aly
Keyword(s):  
Acoustic Wave ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
Geometrical Parameters ◽  
One Dimensional ◽  
Internal Geometry ◽  
Total Length ◽  
Acoustic Filters ◽  
System Length ◽  
Phononic Band Gaps

In this study, we have scrutinized the frequency gap generation by changing the geometrical parameters of a one-dimensional phononic crystal. For this purpose, we have calculated the transmission coefficient of an incident acoustic wave by using the transfer matrix method. We have retained and fixed the total length of the system and changed the system internal geometry not to increase the system length too much. Another reason was to adjust the phononic band gaps and get the desired transmission properties by finding the optimum internal geometry without increasing or decreasing the total length of phononic crystals. In addition, we also propose few structures with the opportunity of applications in acoustical devices such as sonic reflectors. Our results can also be of high interest to design acoustic filters in the case that transmission of certain frequencies is necessary.

PIEZOELECTRIC MATERIAL AND ONE-DIMENSIONAL PHONONIC CRYSTAL

2019 ◽  
Vol 26 (02) ◽  
pp. 1850144 ◽  
Author(s):  
ARAFA H. ALY ◽  
AHMED NAGATY ◽  
Z. KHALIFA
Keyword(s):  
Electric Field ◽  
Piezoelectric Material ◽  
Material Properties ◽  
Phononic Crystal ◽  
Defect Layer ◽  
Phononic Crystals ◽  
Localized Modes ◽  
One Dimensional ◽  
Energy Applications ◽  
Relative Change

We have theoretically obtained the transmittance properties of one-dimensional phononic crystals incorporating a piezoelectric material as a defect layer. We have used the transfer matrix method in our analysis with/without defect materials. By increasing the thickness of the defect layer, we obtained a sharp peak created within the bandgap, that indicates to the significance of defect layer thickness on the band structure. The localized modes and a particular intensity estimated within the bandgap depend on the piezoelectric material properties. By applying different quantities of an external electric field, the position of the peak shifts to different frequencies. The electric field induces a relative change in the piezoelectric thickness. Our structure may be very useful in some applications such as sensors, acoustic switches, and energy applications.

scholarly journals Design and Optimization of a Novel SAW Gyroscope Structure Based on Amplitude Modulation with 1-D Phononic Crystals

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1485
Author(s):  
Fei Ge ◽  
Liye Zhao ◽  
Yang Zhang
Keyword(s):  
Signal Processing ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Amplitude Modulation ◽  
Phononic Crystal ◽  
Defect Mode ◽  
High Sensitivity ◽  
Phononic Crystals ◽  
Linear Range ◽  
One Dimensional

Surface acoustic wave gyroscopes (SAWGs), as a kind of all-solid-state micro-electro-mechanical system (MEMS) gyroscopes, can work normally under extremely high-impact environmental conditions. Among the current SAWGs, amplitude-modulated gyroscopes (AMGs) are all based on the same gyro effect, which was proved weak, and their sensitivity and intensity of the output are both lower than frequency-modulated gyroscopes (FMGs). However, because FMGs need to process a series of frequency signals, their signal processing and circuits are far less straightforward and simple than AMGs. In order to own both high-sensitivity and simple signal processing, a novel surface acoustic traveling wave gyroscope based on amplitude modulation is proposed, using one-dimensional phononic crystals (PCs) in this paper. In view of its specific structure, the proposed gyroscope consists of a surface acoustic wave oscillator and a surface acoustic wave delay line within a one-dimensional phononic crystal with a high-Q defect mode. In this paper, the working principle is analyzed theoretically through the partial wave method (PWM), and the gyroscopes with different numbers of PCs are also designed and studied by using the finite element method (FEM) and multiphysics simulation. The research results demonstrate that under a 1 V oscillator voltage output, the higher sensitivity of −23.1 mV·(rad/s)−1 in the linear range from −8 rad/s to 8 rad/s is reached when the gyro with three PC walls, and the wider linear range from −15 rad/s to 17.5 rad/s with the sensitivity of −6.7 mV·(rad/s)−1 with only one PC wall. Compared with the existing AMGs using metal dots to enhance the gyro effect, the sensitivity of the proposed gyro is increased by 15 to 112 times, and the linear range is increased by 4.6 to 186 times, even without the enhancement of the metal dots.

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.

A Method of Finding Discrete Controls for Switched Dynamical Systems by Applying Continued Fractions

2021 ◽  
Vol 24 (2) ◽  
pp. 175-183
Author(s):  
S. M. Khryashchev
Keyword(s):  
Control Systems ◽  
Discrete Time ◽  
Continuous Time ◽  
Continued Fractions ◽  
Control Method ◽  
Initial State ◽  
Final State ◽  
Control Goal ◽  
Controllability Of Systems ◽  
And Control

Control systems with a finite number of control settings are considered. It is assumed that any polysystem operates in continuous time and control switchings occur at some certain discrete time instants. A control goal is to transfer a polysystem from an initial state to a final state. Controllability of systems switched in discrete time is studied. Controls are constructed by using the theory of generalized multicomponent continued fractions and the congruences theory. Applications of the proposed control method to specific systems are discussed.

Study on Mechanism of One-Dimensional Phononic Crystals with Locally Resonant Structures

2011 ◽  
Vol 287-290 ◽  
pp. 650-653
Author(s):  
Zhuo Fei Song ◽  
Qiang Song Wang ◽  
Zi Dong Wang
Keyword(s):  
Phononic Crystal ◽  
Low Frequency ◽  
Phononic Crystals ◽  
Bragg Scattering ◽  
Scattering Mechanism ◽  
One Dimensional ◽  
Resonant Structures ◽  
Low Frequency Vibration ◽  
Lower Frequency Band ◽  
The One

Comprehensive study is performed for the one-dimensional phononic crystals with locally resonant structures mechanism and Bragg scattering mechanism. Found locally resonant mechanism is same as Bragg scattering mechanism on one-dimension phononic crystal. The reasons of producing lower frequency band gap are still stiffness decrease and quality increase. So the theory that locally resonant structure is better than Bragg scattering in low frequency vibration reduction is inexact.

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.

The Study of Characteristics of Sphere-Radial Phononic Crystals

2011 ◽  
Vol 211-212 ◽  
pp. 609-614 ◽  
Author(s):  
Qi Hua Wen
Keyword(s):  
Phononic Crystal ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Practical Application ◽  
Elastic Wave Equation ◽  
Application Performance ◽  
One Dimensional ◽  
Simulation Results ◽  
The One ◽  
Attenuation Characteristics

By deducing the spherical elastic wave equation in theory, the concept of sphere-radial phononic crystal is proposed, and then the equations to determine the acoustic band structures is deduced. A numerical example is given for steel/nitrile rubber phononic crystal. The numerical simulation results suggest that the band gaps of sphere-radial phononic crystals do exist, which have better attenuation characteristics and practical application performance than the one-dimensional phononic crystals.

scholarly journals Band gap manipulation of viscoelastic functionally graded phononic crystal

2020 ◽  
Vol 9 (1) ◽  
pp. 515-523
Author(s):  
Zuguang Bian ◽  
Shuai Yang ◽  
Xiaoliang Zhou ◽  
David Hui
Keyword(s):  
Incident Angle ◽  
Phononic Crystal ◽  
Functionally Graded ◽  
Band Gaps ◽  
Heat Sources ◽  
Initial State ◽  
Final State ◽  
Sh Waves ◽  
Numerical Examples ◽  
The Matrix

AbstractIn this study, band gaps of SH-waves (horizontally polarized shear waves) propagating in a thermal-sensitive viscoelastic matrix are investigated. Metallic films acting as heat sources are periodically embedded into the matrix, which establishes a periodically inhomogeneous thermal field. The homogenous matrix is therefore transformed into functionally gradient phononic crystals (PCs). A three-parameter solid model is employed to describe the viscoelasticity of the present matrix. By virtue of a transfer matrix method incorporated within a laminated model, the dispersion equation of SH-waves is finally obtained, from which the band gaps are determined. The transmission spectra of a finite-periodic PC are also solved to validate the band gaps. In numerical examples, the influences of incident angles of SH-waves and viscoelasticity of matrix on band gaps are discussed first. Then the research focuses on the means to tune the band gaps by manipulating the inputted powers of heat sources. Numerical examples demonstrate that such a strategy is effective and convenient in tuning the positions and widths of band gaps. A viscous parameter, i.e., the ratio of initial-state to final-state storage moduli, significantly affects the band locations and bandwidths, while the locations of low-order band gaps hardly move with the incident angle of SH-waves. Band gaps of several orders are expected to locate in lower-frequency domain, and the total bandwidth becomes larger as the inputted heat flux increases. This paper lays theoretical foundation to manufacture viscoelastic functionally graded PCs which can be used in frequency-selective devices.

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