Gradient-index based smart metacomposite for elastic wave focusing (Conference Presentation)

2017 ◽  
Author(s):  
Kaijun Yi ◽  
Manuel Collet
Keyword(s):  
Elastic Wave ◽  
Gradient Index ◽  
Wave Focusing

scholarly journals Passive discrete lens for broadband elastic guided wave focusing

2021 ◽  
Author(s):  
Emeline Sadoulet-Reboul ◽  
Gaël Matten ◽  
Kaijun Yi ◽  
Morvan Ouisse
Keyword(s):  
Refractive Index ◽  
Elastic Wave ◽  
Health Monitoring ◽  
Focal Point ◽  
Refractive Index Profile ◽  
Guided Wave ◽  
Gradient Index ◽  
Frequency Range ◽  
Index Profile ◽  
Wave Focusing

Elastic guided wave focusing is of great interest for applications such as vibroacoustic control, energy harvesting, or Structural Health Monitoring. Different strategies allow generation of this effect, GRadient-INdex devices in particular exploit medium with varying properties such as thickness to reproduce an adequate refractive index profile as in optics. The resulting continuous profiles have a curved geometry that can be hard to manufacture, and be difficult to integrate in a given design. The purpose of this paper is to propose a discrete design for a GRIN lens. It is composed of segments selected in number and thickness to give similar focusing effects as a continuous lens profile. The identified configuration is manufactured and bounded on an aluminium plate to evaluate the effective focusing performances. Numerical and experimental vibrometry results confirm that the proposed lens exhibits a fixed focal point over a broad frequency range. The discrete design overcomes fabrication issues encountered in continuous design, allowing for an easier integration in devices for elastic wave control.

Structurally embedded reflectors and mirrors for elastic wave focusing and energy harvesting

2017 ◽  
Vol 122 (16) ◽  
pp. 164503 ◽  
Author(s):  
S. Tol ◽  
F. L. Degertekin ◽  
A. Erturk
Keyword(s):  
Energy Harvesting ◽  
Elastic Wave ◽  
Wave Focusing

scholarly journals Recent Advances in Non-Traditional Elastic Wave Manipulation by Macroscopic Artificial Structures

2020 ◽  
Vol 10 (2) ◽  
pp. 547 ◽  
Author(s):  
Jeonghoon Park ◽  
Dongwoo Lee ◽  
Junsuk Rho
Keyword(s):  
Elastic Wave ◽  
Elastic Waves ◽  
Acoustic Waves ◽  
Electromagnetic Waves ◽  
Gradient Index ◽  
Bragg Scattering ◽  
Elastic Materials ◽  
Artificial Structures ◽  
Elastic Metamaterials ◽  
Gradient Index Lens

Metamaterials are composed of arrays of subwavelength-sized artificial structures; these architectures give rise to novel characteristics that can be exploited to manipulate electromagnetic waves and acoustic waves. They have been also used to manipulate elastic waves, but such waves have a coupling property, so metamaterials for elastic waves uses a different method than for electromagnetic and acoustic waves. Since researches on this type of metamaterials is sparse, this paper reviews studies that used elastic materials to manipulate elastic waves, and introduces applications using extraordinary characteristics induced by metamaterials. Bragg scattering and local resonances have been exploited to introduce a locally resonant elastic metamaterial, a gradient-index lens, a hyperlens, and elastic cloaking. The principles and applications of metasurfaces that can overcome the disadvantages of bulky elastic metamaterials are discussed.

Gradient-index phononic crystals for omnidirectional acoustic wave focusing and energy harvesting

2020 ◽  
Vol 116 (23) ◽  
pp. 234101
Author(s):  
Jaeyub Hyun ◽  
Choon-Su Park ◽  
Jiho Chang ◽  
Wan-Ho Cho ◽  
Miso Kim
Keyword(s):  
Energy Harvesting ◽  
Acoustic Wave ◽  
Phononic Crystals ◽  
Gradient Index ◽  
Wave Focusing

Conformal gradient-index phononic crystal lens for ultrasonic wave focusing in pipe-like structures

2020 ◽  
Vol 117 (2) ◽  
pp. 021906
Author(s):  
Hrishikesh Danawe ◽  
Gorkem Okudan ◽  
Didem Ozevin ◽  
Serife Tol
Keyword(s):  
Ultrasonic Wave ◽  
Phononic Crystal ◽  
Gradient Index ◽  
Wave Focusing

Dramatic Enhancement of Elastic Wave Energy Harvesting Using a Gradient-Index Phononic Crystal Lens

2016 ◽  
Author(s):  
Serife Tol ◽  
F. Levent Degertekin ◽  
Alper Erturk
Keyword(s):  
Energy Harvesting ◽  
Plane Wave ◽  
Elastic Wave ◽  
Wave Energy ◽  
Power Output ◽  
Phononic Crystal ◽  
Gradient Index ◽  
Wave Band ◽  
Wave Excitation ◽  
Elastic Wave Energy

In this paper, we explore structure-borne elastic wave energy harvesting, both numerically and experimentally, by exploiting a Gradient-Index Phononic Crystal Lens (GRIN-PCL) structure. The proposed GRIN-PCL is formed by an array of blind holes with different diameters on an aluminum plate where the orientation and size of the blind holes are tailored to obtain a hyperbolic secant gradient distribution of refractive index guided by finite-element simulations of the lowest asymmetric mode Lamb wave band diagrams. Under plane wave excitation from a line source, experimentally measured wave field successfully validates the numerical simulation of wave focusing within the GRIN-PCL domain. A piezoelectric energy harvester disk located at the first focus of the GRIN-PCL yields an order of magnitude larger power output as compared to the baseline case of energy harvesting without the GRIN-PCL on the uniform plate counterpart for the same incident plane wave excitation. The power output is further improved by a factor of five using complex electrical load impedance matching through resistive-inductive loading as compared to purely resistive loading case.

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