Search of Phononic Crystal Band-Gap about the Array of 2D Square Tube with Slits

2014 ◽  
Vol 536-537 ◽  
pp. 1481-1485
Author(s):  
Long Gen Li ◽  
Yong Gang Chen
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Propagation Characteristic ◽  
Steel Tube ◽  
The Finite Element Method ◽  
Transmission Coefficients ◽  
Square Array

A band structure composed of a square array of parallel steel tube with narrow slits is presented.The propagation characteristic of acoustic waves in this structure is investigated theoretically by the finite element method. In particular the acoustic-solid coupling is taken into account for accurate results. The transmission coefficients of the band system with different angles of the square tubes and slits width are calculated. A large continuous band gap at a low frequency range in a compound structure is obtained due to the interaction of peaks and gaps fordifferent Structural parameters.

scholarly journals Tunable Low Frequency Band Gap and Waveguide of Phononic Crystal Plates with Different Filling Ratio

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Shaobo Zhang ◽  
Jiang Liu ◽  
Hongbo Zhang ◽  
Shuliang Wang
Keyword(s):  
Band Gap ◽  
Composite Structure ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Filling Ratio ◽  
Height Ratio ◽  
Road Vehicles ◽  
Aluminum Base ◽  
Gap Width

Aiming at solving the NVH problem in vehicles, a novel composite structure is proposed. The new structure uses a hollow-stub phononic-crystal with filled cylinders (HPFC) plate. Any unit in the plate consists of a lead head, a silicon rubber body, an aluminum base as outer column and an opposite arranged inner pole. The dispersion curves are investigated by numerical simulations and the influences of structural parameters are discussed, including traditional hollow radius, thickness, height ratio, and the new proposed filling ratio. Three new arrays are created and their spectrum maps are calculated. In the dispersion simulation results, new branches are observed. The new branches would move towards lower frequency zone and the band gap width enlarges as the filling ratio decreases. The transmission spectrum results show that the new design can realize three different multiplexing arrays for waveguides and also extend the locally resonant sonic band gap. In summary, the proposed HPFC structure could meet the requirement for noise guiding and filtering. Compared to a traditional phononic crystal plate, this new composite structure may be more suitable for noise reduction in rail or road vehicles.

Research on low-frequency band gap property of a hybrid phononic crystal

2018 ◽  
Vol 32 (15) ◽  
pp. 1850165 ◽  
Author(s):  
Yake Dong ◽  
Hong Yao ◽  
Jun Du ◽  
Jingbo Zhao ◽  
Ding Chao ◽  
...  
Keyword(s):  
Band Gap ◽  
Transmission Loss ◽  
Displacement Vector ◽  
Phononic Crystal ◽  
Influence Factors ◽  
Low Frequency ◽  
Bragg Scattering ◽  
The Finite Element Method ◽  
Flat Bands ◽  
Resonance Band

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.

scholarly journals Study on Low-Frequency Band Gap Characteristics of a New Helmholtz Type Phononic Crystal

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1379
Author(s):  
Dong-Hai Han ◽  
Jing-Bo Zhao ◽  
Guang-Jun Zhang ◽  
Hong Yao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Band Gap ◽  
Lattice Constant ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Equivalent Model ◽  
Frequency Noise ◽  
The Finite Element Method ◽  
Symmetric Structure

In order to solve the problem of low-frequency noise of aircraft cabins, this paper presents a new Helmholtz type phononic crystal with a two-dimensional symmetric structure. Under the condition of the lattice constant of 62 mm, the lower limit of the first band gap is about 12 Hz, and the width is more than 10 Hz, thus the symmetric structure has distinct sound insulation ability in the low-frequency range. Firstly, the cause of the low-frequency band gap is analyzed by using the sound pressure field, and the range of band gaps is calculated by using the finite element method and the spring-oscillator model. Although the research shows that the finite element calculation results are basically consistent with the theoretical calculation, there are still some errors, and the reasons for the errors are analyzed. Secondly, the finite element method and equivalent model method are used to explore the influence of parameters of the symmetric structure on the first band gap. The result shows that the upper limit of the first band gap decreases with the increase of the lattice constant and the wedge height and increases with the increase of the length of wedge base; the lower limit of the band gap decreases with the increase of the wedge height and length of wedge base and is independent of the change of lattice constant, which further reveals the essence of the band gap formation and verifies the accuracy of the equivalent model. This study provides some theoretical support for low-frequency noise control and broadens the design idea of symmetric phononic crystal.

Application of phononic crystals for vibration reduction and noise reduction of wheel-driven electric buses based on neural networks

2021 ◽  
pp. 095440702110359
Author(s):  
Boqiang Zhang ◽  
Penghui Chen ◽  
Huiyong Chen ◽  
Tianpei Feng ◽  
Chengxin Cai ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Band Gap ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Phononic Crystals ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
System A ◽  
Electric Bus

Because of the position of the motor and the excitation of the suspension system, a wheel-driven electric bus produces low-frequency noise, which is difficult to resolve through traditional sound absorption and noise reduction technology. Through an interior noise test of a wheel-driven electric bus, we found that the interior low-frequency noise had a considerable influence on the driver. In order to solve this problem, a locally resonant phononic crystal was used to meet the requirements of vibration and noise reduction for the wheel-driven electric bus. The intrinsic relationship between the band gap distribution of the locally resonant phononic crystal and the topology was established by training a neural network, so as to achieve the desired effect of the bandgap model on the basis of the input bandgap range. Upon an increase in the number of models, the prediction model error decreased gradually. This method could quickly obtain the structural parameters of the locally resonant phononic crystal with the expected band gap, which made it convenient to apply locally resonant phononic crystals to the vibration and noise reduction of wheel-driven electric buses and in other fields.

Bandgaps characteristics of the periodical slit metal tubes with backstraps

2017 ◽  
Vol 31 (15) ◽  
pp. 1750125 ◽  
Author(s):  
Kai Bao ◽  
Tianning Chen ◽  
Xiaopeng Wang ◽  
Ailing Song ◽  
Lele Wan
Keyword(s):  
Acoustic Waves ◽  
Mass Density ◽  
Phononic Crystal ◽  
Location Parameter ◽  
Slit Width ◽  
The Finite Element Method ◽  
Frequency Range ◽  
Transmission Coefficients ◽  
Helmholtz Resonators ◽  
Location Parameters

In this paper, a new two-dimensional (2D) phononic crystal structure composed of periodic slit metal tubes, in which the unit cell consists of straight or curved backstraps, is proposed, and the propagation characteristics of acoustic waves in this structure are theoretically investigated. Using the finite-element method, we calculate the dispersion relations and transmission coefficients of this structure. The results show that, in contrast to the only slit metal tubes, the periodic slit metal tubes with straight or curved backstraps are proved to display band gaps (BGs) at much lower frequency range. Meanwhile, the effect of the slit width of the backstraps on the BGs is investigated. The results show that the positions and widths of the BGs can be effectively modulated by the backstraps without changing the mass density or lattice constant of the material. The lowest frequency falls by about 200 Hz. Moreover, we investigated how the BGs are affected by the location parameter of the backstraps, finding that the acoustic BGs are sensitive to the location parameter of the backstraps. Numerical results show that BGs are significantly dependent upon the slit width and location parameters of the backstraps. The BGs are optimized because, the effect of the Helmholtz resonators of the slit tube is strengthened and changed when the location and slit width of the backstraps change. These results provide a good reference for optimizing BGs, generating filters and designing devices.

scholarly journals Locally Resonant Phononic Crystals at Low frequencies Based on Porous SiC Multilayer

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ahmed Mehaney ◽  
Ashour M. Ahmed
Keyword(s):  
Band Gap ◽  
Frequency Band ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Band Gaps ◽  
Resonance Phenomenon ◽  
Porous Sic ◽  
Phononic Band Gaps ◽  
Sound Suppression

Abstract In this work, a one-dimensional porous silicon carbide phononic crystal (1D-PSiC PnC) sandwiched between two rubber layers is introduced to obtain low frequency band gaps for the audible frequencies. The novelty of the proposed multilayer 1D-PnCs arises from the coupling between the soft rubber, unique mechanical properties of porous SiC materials and the local resonance phenomenon. The proposed structure could be considered as a 1D acoustic Metamaterial with a size smaller than the relevant 1D-PnC structures for the same frequencies. To the best of our knowledge, it is the first time to use PSiC materials in a 1D PnC structure for the problem of low frequency phononic band gaps. Also, the porosities and thicknesses of the PSiC layers were chosen to obtain the fundamental band gaps within the bandwidth of the acoustic transducers and sound suppression devices. The transmission spectrum of acoustic waves is calculated by using the transfer matrix method (TMM). The results revealed that surprising low band gaps appeared in the transmission spectra of the 1D-PSiC PnC at the audible range, which are lower than the expected ones by Bragg’s scattering theory. The frequency at the center of the first band gap was at the value 7957 Hz, which is 118 times smaller than the relevant frequency of other 1D structures with the same thickness. A comparison between the phononic band gaps of binary and ternary 1D-PSiC PnC structures sandwiched between two rubber layers at the micro-scale was performed and discussed. Also, the band gap frequency is controlled by varying the layers porosity, number and the thickness of each layer. The simulated results are promising in many applications such as low frequency band gaps, sound suppression devices, switches and filters.

A Novel Micromechanical Resonator Using Two-Dimensional Phononic Crystal Slab

2011 ◽  
Vol 254 ◽  
pp. 195-198
Author(s):  
Nan Wang ◽  
Fu Li Hsiao ◽  
Moorthi Palaniapan ◽  
Ming Lin Julius Tsai ◽  
Jeffrey B.W. Soon ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Phononic Crystal ◽  
Acoustic Resonance ◽  
Two Dimensional ◽  
Free Standing ◽  
Sensing Applications ◽  
Aln Film ◽  
Digital Transducers ◽  
Square Array ◽  
Quality Factor Q

Two-dimensional (2-D) Silicon phononic crystal (PnC) slab of a square array of cylindrical air holes in a 10μm thick free-standing silicon plate with line defects is characterized as a cavity-mode PnC resonator. Piezoelectric aluminum nitride (AlN) film is deployed as the inter-digital transducers (IDT) to transmit and detect acoustic waves, thus making the whole microfabrication process CMOS-compatible. Both the band structure of the PnC and the transmission spectrum of the proposed PnC resonator are analyzed and optimized using finite element method (FEM). The measured quality factor (Q factor) of the microfabricated PnC resonator is over 1,000 at its resonant frequency of 152.46MHz. The proposed PnC resonator shows promising acoustic resonance characteristics for RF communications and sensing applications.

Tunable Nonlinear Band Gaps in a Sandwich-Like Meta-Plate

2021 ◽  
Author(s):  
Yu Xue ◽  
Jinqiang Li ◽  
Yu Wang ◽  
Fengming Li
Keyword(s):  
Band Gap ◽  
Vibration Suppression ◽  
Wave Attenuation ◽  
Structural Parameters ◽  
Low Frequency ◽  
Dispersion Analysis ◽  
Response Analysis ◽  
Working Mechanism ◽  
Frequency Wave ◽  
The Galerkin Method

Abstract This paper aims to explore the actual working mechanism of sandwich-like meta-plates by periodically attaching nonlinear mass-beam-spring (MBS) resonators for low-frequency wave absorption. The nonlinear MBS resonator consists of a mass, a cantilever beam and a spring that can provide negative stiffness in the transverse vibration of the resonator, and its stiffness is tunable by changing the parameters of the spring. Considering the nonlinear stiffness of the resonator, the energy method is applied to obtain the dispersion relation of the sandwich-like meta-plate and the band-gap bounds related to the amplitude of resonator is derived by dispersion analysis. For the finite sized sandwich-like meta-plate with the fully free boundary condition subjected to external excitations, its dynamic equation is also established by the Galerkin method. The frequency response analysis of the meta-plate is carried out by the numerical simulation, whose band-gap range demonstrates good agreement with the theoretical one. Results show that the band-gap range of the present meta-plate is tunable by the design of the structural parameters of the MBS resonator. Furthermore, by analyzing the vibration suppression of the finite sized meta-plate, it can be observed that the nonlinearity of resonators can widen the wave attenuation range of meta-plate.

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.

Acoustic Band Gap Extension in One-Dimensional Solid/Fluid Phononic Crystal Heterostructure

2014 ◽  
Vol 22 (04) ◽  
pp. 1450010 ◽  
Author(s):  
Xu Yang Xiao ◽  
Run Ping Chen
Keyword(s):  
Band Gap ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Wide Band ◽  
Normal Incidence ◽  
Wide Band Gap ◽  
Longitudinal Waves ◽  
One Dimensional ◽  
Solid Media ◽  
Fluid Media

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.

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