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

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.

2011 ◽  
Vol 211-212 ◽  
pp. 609-614 ◽  
Author(s):  
Qi Hua Wen

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.


Author(s):  
Chittaranjan Nayak ◽  
Mehdi Solaimani ◽  
Alireza Aghajamali ◽  
Arafa H. Aly

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.


2019 ◽  
Vol 26 (02) ◽  
pp. 1850144 ◽  
Author(s):  
ARAFA H. ALY ◽  
AHMED NAGATY ◽  
Z. KHALIFA

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.


2020 ◽  
Vol 14 (5) ◽  
Author(s):  
Zheng-wei Li ◽  
Xin-sheng Fang ◽  
Bin Liang ◽  
Yong Li ◽  
Jian-chun Cheng

2014 ◽  
Vol 22 (04) ◽  
pp. 1450010 ◽  
Author(s):  
Xu Yang Xiao ◽  
Run Ping Chen

The propagation of elastic longitudinal waves in one-dimensional (1D) phononic crystals (PNCs) consisting of alternating solid and fluid media is comprehensively analyzed in theory. We demonstrate the acoustic band gap (ABG) structure determined by the dispersion relation for longitudinal waves at normal incidence. According to the band structure, we design a sub-PNC by setting a reasonable thickness ratio of fluid and solid media, and then form a phononic heterostructure by merging this PNC and other PNC designed in advance. We have shown that the wide band gap exists in such a phononic heterostructure for elastic longitudinal waves at normal incidence. For oblique incidence, the wide band gap shifts towards high frequency regions, meanwhile a low-frequency band gap is split.


2017 ◽  
Vol 31 (11) ◽  
pp. 1750127 ◽  
Author(s):  
Yake Dong ◽  
Hong Yao ◽  
Jun Du ◽  
Jingbo Zhao ◽  
Jiulong Jiang

Based on the finite element method (FEM), characteristics of the local resonance band gap and the Bragg scattering band gap of two periodically-distributed vibrator structures are studied. Conditions of original anti-resonance generation are theoretically derived. The original anti-resonance effect leads to localization of vibration. Factors which influence original anti-resonance band gap are analyzed. The band gap width and the mass ratio between two vibrators are closely correlated to each other. Results show that the original anti-resonance band gap has few influencing factors. In the locally resonant structure, the Bragg scattering band gap is found. The mass density of the elastic medium and the elasticity modulus have an important impact on the Bragg band gap. The coexistence of the two mechanisms makes the band gap larger. The band gap covered 90% of the low frequencies below 2000 Hz. All in all, the research could provide references for studying the low-frequency and broad band gap of phononic crystal.


2018 ◽  
Vol 32 (15) ◽  
pp. 1850165 ◽  
Author(s):  
Yake Dong ◽  
Hong Yao ◽  
Jun Du ◽  
Jingbo Zhao ◽  
Ding Chao ◽  
...  

A hybrid phononic crystal has been investigated. The characteristic frequency of XY mode, transmission loss and displacement vector have been calculated by the finite element method. There are Bragg scattering band gap and local resonance band gap in the band structures. We studied the influence factors of band gap. There are many flat bands in the eigenfrequencies curve. There are many flat bands in the curve. The band gap covers a large range in low frequency. The band gaps cover more than 95% below 3000 Hz.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1485
Author(s):  
Fei Ge ◽  
Liye Zhao ◽  
Yang Zhang

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.


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