Wave attenuation and dissipation mechanisms in viscoelastic phononic crystals

The current century witnessed an overwhelming research interest in phononic crystals (PnCs) and acoustic metamaterials (AMs) research owing to their fantastic properties in manipulating acoustic and elastic waves that are inconceivable from naturally occurring materials. Extensive research literature about the dynamical and mechanical properties of acoustic metamaterials currently exists, and this maturing research field is now finding possible industrial and infrastructural applications. The present study proposes a novel 3D composite multilayered phononic pillars capable of inducing two-dimensional and three-dimensional complete bandgaps (BGs). A phononic structure that consisted of silicon and tungsten layers was subjected to both plane and surface acoustic waves in three-dimensional and two-dimensional periodic systems, respectively. By frequency response study, the wave attenuation, trapping/localization, transmission, and defect analysis was carried out for both plane and surface acoustic waves. In the bandgap, the localized defect state was studied for both plane and surface acoustic waves separately. At the defect state, the localization of both plane and surface acoustic waves was observed. By varying the defect size, the localized frequency can be made tailorable. The study is based on a numerical technique, and it is validated by comparison with a reported theoretical work. The findings may provide a new perspective and insight for the designs and applications of three-dimensional phononic crystals for surface acoustic wave and plane wave manipulation, particularly for energy harvesting, sensing, focusing and waves isolation/attenuation purposes.

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Flexural Wave Attenuation in a Multi-Frequency Locally Resonant Phononic Crystals Beam Resting on Elastic Foundations

Geo-Congress 2020 ◽

10.1061/9780784482810.007 ◽

2020 ◽

Author(s):

C. Li ◽

L. C. Miao ◽

Q. You ◽

X. D. Liang ◽

L. J. Lei

Keyword(s):

Wave Attenuation ◽

Phononic Crystals ◽

Flexural Wave ◽

Elastic Foundations

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

Journal of Vibration and Acoustics ◽

10.1115/1.4048394 ◽

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.

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Spider Web-Like Phononic Crystals for Piezoelectric Mems Resonators to Reduce Acoustic Energy Dissipation

Micromachines ◽

10.3390/mi10090626 ◽

2019 ◽

Vol 10 (9) ◽

pp. 626 ◽

Cited By ~ 5

Author(s):

Bao ◽

Wu ◽

Zhou ◽

Wu ◽

Zhang ◽

...

Keyword(s):

Energy Dissipation ◽

Wave Attenuation ◽

Phononic Crystals ◽

Acoustic Energy ◽

Acoustic Metamaterials ◽

Element Analysis ◽

Micro Electro Mechanical Systems ◽

Spider Web ◽

Mems Resonators ◽

Energy Leakage

Phononic crystals (PnC) are a remarkable example of acoustic metamaterials with superior wave attenuation mechanisms for piezoelectric micro-electro-mechanical systems (MEMS) resonators to reduce the energy dissipation. Herein, a spider web-like PnC (SW-PnC) is proposed to sufficiently isolate the wave vibration. Finite-element analysis is performed to gain insight into the transmission property of finite PnC, and band characteristics by infinite periods. In comparison with the circle hole PnC at a similar bandgap, due to its already very lightweight PnC structure compared with previously reported PnCs, the proposed PnC offers a significantly lighter weight, smaller lattice constant, and greater energy leakage inhibition. More specifically, the resonator with the SW-PnC plate as the anchoring substrate exhibited a quality factor as high as 66569.7 at 75.82 MHz.

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THE ANALYSIS OF ULTRASONIC WAVE ATTENUATION SPECTRA IN STEELS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1983948 ◽

1983 ◽

Vol 44 (C9) ◽

pp. C9-337-C9-340 ◽

Cited By ~ 1

Author(s):

R. L. Smith ◽

W. N. Reynolds ◽

S. Perring

Keyword(s):

Ultrasonic Wave ◽

Wave Attenuation

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Bulk drag coefficient of a subaquatic vegetation subjected to irregular waves: Influence of Reynolds and Keulegan-Carpenter numbers

La Houille Blanche ◽

10.1051/lhb/2020015 ◽

2020 ◽

pp. 34-42

Author(s):

Thibault Chastel ◽

Kevin Botten ◽

Nathalie Durand ◽

Nicole Goutal

Keyword(s):

Drag Coefficient ◽

Wave Height ◽

Wave Attenuation ◽

Empirical Relationship ◽

Breaking Waves ◽

Irregular Waves ◽

Geometrical Parameters ◽

Flume Experiments ◽

Seagrass Meadows ◽

Artificial Vegetation

Seagrass meadows are essential for protection of coastal erosion by damping wave and stabilizing the seabed. Seagrass are considered as a source of water resistance which modifies strongly the wave dynamics. As a part of EDF R & D seagrass restoration project in the Berre lagoon, we quantify the wave attenuation due to artificial vegetation distributed in a flume. Experiments have been conducted at Saint-Venant Hydraulics Laboratory wave flume (Chatou, France). We measure the wave damping with 13 resistive waves gauges along a distance L = 22.5 m for the “low” density and L = 12.15 m for the “high” density of vegetation mimics. A JONSWAP spectrum is used for the generation of irregular waves with significant wave height Hs ranging from 0.10 to 0.23 m and peak period Tp ranging from 1 to 3 s. Artificial vegetation is a model of Posidonia oceanica seagrass species represented by slightly flexible polypropylene shoots with 8 artificial leaves of 0.28 and 0.16 m height. Different hydrodynamics conditions (Hs, Tp, water depth hw) and geometrical parameters (submergence ratio α, shoot density N) have been tested to see their influence on wave attenuation. For a high submergence ratio (typically 0.7), the wave attenuation can reach 67% of the incident wave height whereas for a low submergence ratio (< 0.2) the wave attenuation is negligible. From each experiment, a bulk drag coefficient has been extracted following the energy dissipation model for irregular non-breaking waves developed by Mendez and Losada (2004). This model, based on the assumption that the energy loss over the species meadow is essentially due to the drag force, takes into account both wave and vegetation parameter. Finally, we found an empirical relationship for Cd depending on 2 dimensionless parameters: the Reynolds and Keulegan-Carpenter numbers. These relationships are compared with other similar studies.

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