Coupled Piezoelectric Phononic Crystal for Adaptive Broadband Wave Attenuation by Destructive Interference

2020 ◽  
Vol 87 (9) ◽  
Author(s):  
Jiawen Xu ◽  
Xin Zhang ◽  
Ruqiang Yan
Keyword(s):  
Phase Difference ◽  
Wave Attenuation ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Crystal Plate ◽  
Destructive Interference ◽  
Negative Capacitance ◽  
Frequency Range ◽  
Frequency Wave ◽  
Unit Cells

Abstract In this paper, we report a piezoelectric phononic crystal plate featuring broadband wave attenuation. In the piezoelectric phononic crystal system, the transmitted elastic wave is attenuated owing to destructive interference by taking advantages of phase difference. The proposed concept is applied to a piezoelectric phononic crystal plate synthesized by functional dual-lane units that yields phase difference. Whereas, the piezoelectric unit-cells are connected negative capacitance shunt circuits individually. Our analysis shows that the coupled phononic crystal has a strong broadband low-frequency wave attenuation capability. The bandwidth of 10 dB wave attenuation is broadened by 34 times in the vicinity of 5 kHz comparing to that of a local resonance metamaterial under the same mechanical configuration. Moreover, the frequency range of wave attenuation of the proposed system can be online adjusted through the modification of the external shunt circuits.

Modeling and Analysis of Phononic Crystal With Coupled Lanes for Enhanced Elastic Wave Attenuation

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Jiawen Xu ◽  
Guobiao Hu ◽  
Lihua Tang ◽  
Yumin Zhang ◽  
Ruqiang Yan
Keyword(s):  
Elastic Wave ◽  
Phase Difference ◽  
Wave Attenuation ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Fem Analysis ◽  
Phononic Crystals ◽  
Attractive Potential ◽  
Destructive Interference ◽  
Unit Cells

Abstract Phononic crystals and metamaterials have attractive potential in elastic wave attenuation and guiding over specific frequency ranges. Different from traditional phononic crystals/metamaterials consisting of identical unit cells, a phononic crystal with coupled lanes is reported in this article for enhanced elastic wave attenuation in the low-frequency regime. The proposed phononic crystal takes advantages of destructive interference mechanism. A finitely length phononic crystal plate consisting of coupled lanes is considered for conceptual verification. The coupled lanes are designed to split the incident elastic wave into separated parts with a phase difference to produce destructive interference. Theoretical modeling and finite element method (FEM) analysis are presented. It is illustrated that significant elastic wave attenuation is realized when the phase difference of elastic waves propagating through the coupled lanes approximates π. Besides, multiple valleys in the transmission can be achieved in a broad frequency range with one at a frequency as low as 1.85 kHz with unit cells’ width and length of 25 mm and ten unit cells in one lane.

A novel metal-matrix phononic crystal with a low-frequency, broad and complete, locally-resonant band gap

2018 ◽  
Vol 32 (19) ◽  
pp. 1850221 ◽  
Author(s):  
Suobin Li ◽  
Yihua Dou ◽  
Tianning Chen ◽  
Zhiguo Wan ◽  
Zhengrong Guan
Keyword(s):  
Band Gap ◽  
Metal Matrix ◽  
Steel Plate ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Crystal Plate ◽  
Band Gaps ◽  
Frequency Range ◽  
Low Frequency Vibration ◽  
Out Of Plane

In this paper, a novel metal-matrix phononic crystal with a low-frequency, broad and complete, locally-resonant band gap, which includes the in-plane and out-of-plane band gaps, is investigated numerically. The proposed structure consists of double-sided single “hard” cylinder stubs, which are deposited on a two-dimensional locally-resonant phononic-crystal plate that consists of an array of rubber fillers embedded in a steel plate. Our results indicate that both the out-of-plane band gap and the in-plane band gap increase after introducing single “hard” cylinder stubs. More specifically, the out-of-plane band gap is increased by the out-of-plane analogous-rigid mode, while the in-plane band gap is increased by the in-plane analogous-rigid mode. The out-of-plane and the in-plane analogous-rigid mode are formed after introduction of the single “hard” cylinder stub. As a result, a broad, complete locally-resonant band gap in the low frequency is obtained due to the broad in-plane and out-of-plane band gaps overlapping. Compared to the classical double-sided stubbed metal-matrix phononic-crystal plate, the absolute bandwidth of the complete band gap is increased by a factor of 4.76 in the proposed structure. Furthermore, the effect of simple “hard” stubs on complete band gaps is investigated. The results show that the location of the complete band gaps can be modulated using a low frequency, and the bandwidth can be extended to a larger frequency range using different “hard” stubs. The new structure provides an effective way for metal-matrix phononic crystals to obtain broad and complete locally-resonant band gaps in the low-frequency range, which has many applications for low-frequency vibration reduction.

scholarly journals Tunable characteristics of low-frequency bandgaps in two-dimensional multivibrator phononic crystal plates under prestrain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hai-Fei Zhu ◽  
Xiao-Wei Sun ◽  
Ting Song ◽  
Xiao-Dong Wen ◽  
Xi-Xuan Liu ◽  
...  
Keyword(s):  
Phononic Crystal ◽  
Real Life ◽  
Low Frequency ◽  
Acoustic Vibration ◽  
Crystal Plate ◽  
Frequency Noise ◽  
Two Dimensional ◽  
The Matrix ◽  
Noise Frequency ◽  
Realtime Control

AbstractIn view of the influence of variability of low-frequency noise frequency on noise prevention in real life, we present a novel two-dimensional tunable phononic crystal plate which is consisted of lead columns deposited in a silicone rubber plate with periodic holes and calculate its bandgap characteristics by finite element method. The low-frequency bandgap mechanism of the designed model is discussed simultaneously. Accordingly, the influence of geometric parameters of the phononic crystal plate on the bandgap characteristics is analyzed and the bandgap adjustability under prestretch strain is further studied. Results show that the new designed phononic crystal plate has lower bandgap starting frequency and wider bandwidth than the traditional single-sided structure, which is due to the coupling between the resonance mode of the scatterer and the long traveling wave in the matrix with the introduction of periodic holes. Applying prestretch strain to the matrix can realize active realtime control of low-frequency bandgap under slight deformation and broaden the low-frequency bandgap, which can be explained as the multiple bands tend to be flattened due to the localization degree of unit cell vibration increases with the rise of prestrain. The presented structure improves the realtime adjustability of sound isolation and vibration reduction frequency for phononic crystal in complex acoustic vibration environments.

A waveform inversion technique for measuring elastic wave attenuation in cylindrical bars

Geophysics ◽  
1992 ◽  
Vol 57 (6) ◽  
pp. 854-859 ◽  
Author(s):  
Xiao Ming Tang
Keyword(s):  
Elastic Wave ◽  
Wave Attenuation ◽  
Waveform Inversion ◽  
Finite Size ◽  
Low Frequency ◽  
Frequency Range ◽  
Multiple Reflections ◽  
Low Frequencies ◽  
The Time Domain ◽  
Attenuation Values

A new technique for measuring elastic wave attenuation in the frequency range of 10–150 kHz consists of measuring low‐frequency waveforms using two cylindrical bars of the same material but of different lengths. The attenuation is obtained through two steps. In the first, the waveform measured within the shorter bar is propagated to the length of the longer bar, and the distortion of the waveform due to the dispersion effect of the cylindrical waveguide is compensated. The second step is the inversion for the attenuation or Q of the bar material by minimizing the difference between the waveform propagated from the shorter bar and the waveform measured within the longer bar. The waveform inversion is performed in the time domain, and the waveforms can be appropriately truncated to avoid multiple reflections due to the finite size of the (shorter) sample, allowing attenuation to be measured at long wavelengths or low frequencies. The frequency range in which this technique operates fills the gap between the resonant bar measurement (∼10 kHz) and ultrasonic measurement (∼100–1000 kHz). By using the technique, attenuation values in a PVC (a highly attenuative) material and in Sierra White granite were measured in the frequency range of 40–140 kHz. The obtained attenuation values for the two materials are found to be reliable and consistent.

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 Geomagnetic activity and local time dependence of the distribution of ultra low-frequency wave power in azimuthal wavenumbers, <i>m</i>

2017 ◽  
Vol 35 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Theodore E. Sarris ◽  
Xinlin Li
Keyword(s):  
Phase Difference ◽  
Low Frequency ◽  
Field Measurements ◽  
Resonant Interaction ◽  
Total Power ◽  
Ulf Waves ◽  
Quiet Time ◽  
Frequency Wave ◽  
Drift Frequency ◽  
Diffusion Rates

Abstract. The azimuthal wavenumber m of ultra low-frequency (ULF) waves in the magnetosphere is a required parameter in the calculations of the diffusion rates of energetic electrons and protons in the magnetosphere, as electrons and protons of drift frequency ωd have been shown to radially diffuse due to resonant interaction with ULF waves of frequency ω = mωd. However, there are difficulties in estimating m, due to lack of multipoint measurements. In this paper we use magnetic field measurements at geosynchronous orbit to calculate the cross-spectrogram power and phase differences between time series from magnetometer pairs. Subsequently, assuming that ULF waves of a certain frequency and m would be observed with a certain phase difference between two azimuthally aligned magnetometers, the fraction of the total power in each phase difference range is calculated. As part of the analysis, both quiet-time and storm-time distributions of power per m number are calculated, and it is shown that during active times, a smaller fraction of total power is confined to lower m than during quiet times. It is also shown that in the dayside region, power is distributed mostly to the lowest azimuthal wavenumbers m = 1 and 2, whereas on the nightside it is more equally distributed to all m that can be resolved by the azimuthal separation between two spacecraft.

scholarly journals Optimization of a type of elastic metamaterial for broadband wave suppression

2021 ◽  
Vol 477 (2251) ◽  
pp. 20210337
Author(s):  
Kun Wu ◽  
Haiyan Hu ◽  
Lifeng Wang
Keyword(s):  
Vibration Isolation ◽  
Wave Attenuation ◽  
Low Frequency ◽  
Dispersion Analysis ◽  
Mass Unit ◽  
Super Cell ◽  
Unit Cells ◽  
Sequential Quadratic Programming Method ◽  
Continuous Frequency ◽  
Quadratic Programming Method

The optimal design is studied for a type of one-dimensional dissipative metamaterial to achieve broadband wave attenuation at low-frequency ranges. The complex dispersion analysis is made on a super-cell consisting of multiple mass-in-mass unit cells. An optimization algorithm based on the sequential quadratic programming method is used to design the wave suppression of target frequencies by coupling multiple separate narrow bandgaps into a broad bandgap. A new objective function is proposed in the optimization process for a continuous bandgap. Then, the continuous frequency range with low-wave transmissibility is optimized to achieve the maximal width of bandgap. The stiffness optimization of super-cell gives the broad bandgap from 10 Hz to 22.9 Hz at low-frequency ranges. In addition, numerical simulations are conducted for a type of dissipative metamaterial composed of a finite number of periodicities. The level of vibration isolation can be tuned by adjusting a critical value in the optimization scheme. The wave suppression in the numerical simulation well coincides with the obtained bandgaps and verifies the optimization results.

Evaluation of an Extended Operational Boussinesq-Type Wave Model for Calculating Low-Frequency Waves in Intermediate Depths

2011 ◽  
Author(s):  
Martijn P. C. de Jong ◽  
Mart Borsboom ◽  
Jan A. M. de Bont ◽  
Bas van Vossen
Keyword(s):  
Low Frequency ◽  
Wave Model ◽  
Coastal Engineering ◽  
Extended Model ◽  
Depth Range ◽  
Frequency Range ◽  
Frequency Wave ◽  
Type Wave ◽  
Wave Heights ◽  
Low Frequency Waves

The motions of (LNG) vessels moored offshore at depths ranging from about 20 to 100 m may depend significantly on the presence of (bound) low-frequency waves with periods in the order of 100 s. This is because these moored vessels show a large motion response in this frequency range and because the energy contents of low-frequency waves at these ‘intermediate’ depths is relatively large. As part of the Joint Industry Project HawaI, the operational Boussinesq-type wave model of Deltares, TRITON, was used to investigate whether this type of wave models could predict bound low-frequency waves (setdown waves) at intermediate depths. Comparison to measured and theoretical data, however, showed an underestimation of the computed levels of bound low-frequency wave heights for this depth range by a factor 2 to 4. Recently, additional tests were made with TRITON in situations for which the model has been designed: coastal engineering applications in shallow water (depths up to at most 20 m). These also showed an underestimation of the bound low-frequency wave heights, albeit smaller, up to a factor 2. In view of the importance of the energy contained in the low-frequency range for certain nearshore and shoreline processes, such as morphological processes, this underestimation is also of concern in coastal engineering. This triggered the development of a higher-order extension of the TRITON model equations (Borsboom, 2008, Wellens, 2010), with the aim to improve the accuracy of the model for long waves while still keeping computational times within acceptable (operational) limits. This paper reports on the usefulness of the extended model for the field of application considered in JIP HawaI/II: providing wave data for calculating the motions of vessels moored in intermediate depths. The results show a significant improvement of the modeling of nonlinear wave dynamics, including the prediction of bound low-frequency waves. This means that the model extension is an important step towards an operational Boussinesq-type wave model with sufficient accuracy in both the wave-frequency (sea, swell) and the low-frequency range for applications in intermediate depths.

Determining the depth of surface charging layer of single Prussian blue nanoparticles with pseudocapacitive behaviors

2021 ◽  
Author(s):  
wei Wang ◽  
Ben Niu ◽  
Wenxuan Jiang ◽  
Mengqi Lv ◽  
Sa Wang
Keyword(s):  
Prussian Blue ◽  
Electrochemical Impedance ◽  
Modulation Frequency ◽  
Low Frequency ◽  
Frequency Range ◽  
Force Microscopy ◽  
Surface Charging ◽  
Prussian Blue Nanoparticles ◽  
Unit Cells ◽  
Pseudocapacitive Behavior

Abstract Based on the dependence of the light scattering intensity of single Prussian blue nanoparticles (PBNPs) on their oxidation state during sinusoidal potential modulation at varying frequencies, we present an electro-optical microscopic imaging approach to optically acquire the Faradaic electrochemical impedance spectroscopy (oEIS) of single PBNPs. Frequency analysis revealed typical pseudocapacitive behavior with hybrid charge-storage mechanisms depending on the modulation frequency. In the low-frequency range (0.04–1 Hz), the optical amplitude was inversely proportional to the square root of the modulation frequency (i.e., ∆I ∝ f− 0.5; diffusion-limited process), while in the high-frequency range (1.25–100 Hz), it was inversely proportional to the modulation frequency (∆I ∝ f− 1; surface charging process). The contribution of each process was, therefore, determined and quantified using oEIS at the single-nanoparticle level. Because the geometry of single cuboid-shaped PBNPs can be precisely determined by scanning electron microscopy and atomic force microscopy, oEIS of single PBNPs allowed the determination of the depth of the surface charging layer, revealing it to be ~ 2 unit cells regardless of the nanoparticle size.

On the mechanisms of low-frequency wave attenuation by muddy seabeds

2014 ◽  
Vol 41 (8) ◽  
pp. 2870-2875 ◽  
Author(s):  
Alec Torres-Freyermuth ◽  
Tian-Jian Hsu
Keyword(s):  
Wave Attenuation ◽  
Low Frequency ◽  
Frequency Wave
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