Phononic crystal Luneburg lens for omnidirectional elastic wave focusing and energy harvesting

2017 ◽  
Vol 111 (1) ◽  
pp. 013503 ◽  
Author(s):  
S. Tol ◽  
F. L. Degertekin ◽  
A. Erturk
Keyword(s):  
Energy Harvesting ◽  
Elastic Wave ◽  
Phononic Crystal ◽  
Wave Focusing ◽  
Luneburg Lens

Enhanced energy transfer and conversion for high performance phononic crystal-assisted elastic wave energy harvesting

Nano Energy ◽  
2020 ◽  
Vol 78 ◽  
pp. 105226 ◽  
Author(s):  
Tae-Gon Lee ◽  
Soo-Ho Jo ◽  
Hong Min Seung ◽  
Sun-Woo Kim ◽  
Eun-Ji Kim ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Energy Harvesting ◽  
Elastic Wave ◽  
Wave Energy ◽  
High Performance ◽  
Phononic Crystal ◽  
Elastic Wave Energy

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

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.

Low-Frequency Elastic Wave Focusing and Harvesting via Locally Resonant Metamaterials

2017 ◽  
Author(s):  
Serife Tol ◽  
F. Levent Degertekin ◽  
Alper Erturk
Keyword(s):  
Refractive Index ◽  
Elastic Wave ◽  
Resonance Frequency ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Refractive Index Profile ◽  
Index Profile ◽  
Wave Focusing ◽  
Local Resonance ◽  
Unit Cells

Elastic lens and mirror concepts that have been explored to date for enhanced structure-borne wave energy harvesting are suitable for relatively high-frequency waves (e.g. tens of kHz), which are very much outside the typical ambient structural frequency energy spectrum. One direct way of reducing the design frequency of such phononic crystal-based lens and reflector/mirror designs is to increase their size, which would yield very large dimensions to operate at ambient vibration frequencies (∼hundreds of Hz). In this work, we exploit locally resonant (LR) metamaterials to enable low-frequency elastic wave focusing via LR lens and mirror concepts with practical size limitations. LR lens is designed in a similar way to its phononic crystal counterpart by tailoring the refractive index profile of the LR unit cell distribution. However, LR approach enables altering the dispersion characteristics, and thereby the phase velocity distribution, at much lower frequencies right below the local resonance frequency. Other than the local resonance frequency of the unit cells, the key factor in design is the mass ratio of the resonators to achieve a desired refractive index profile and focusing. LR mirror uses the low-frequency bandgap which is right above the resonance frequency of the unit cells. LR unit cells arranged in the form of a parabola, for instance, makes a low-frequency LR mirror that operates in the bandgap for plane wave focusing. These LR focusing concepts can be used in vibration civil, aerospace, and mechanical systems to localize and harvest structure-borne wave energy.

scholarly journals A Phononic Crystal with Differently Configured Double Defects for Broadband Elastic Wave Energy Localization and Harvesting

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 643
Author(s):  
Soo-Ho Jo ◽  
Byeng D. Youn
Keyword(s):  
Elastic Wave ◽  
Wave Energy ◽  
Phononic Crystal ◽  
Square Lattice ◽  
Energy Localization ◽  
Piezoelectric Patch ◽  
Single Defect ◽  
Piezoelectric Energy ◽  
Piezoelectric Effects ◽  
Elastic Wave Energy

Several previous studies have been dedicated to incorporating double defect modes of a phononic crystal (PnC) into piezoelectric energy harvesting (PEH) systems to broaden the bandwidth. However, these prior studies are limited to examining an identical configuration of the double defects. Therefore, this paper aims to propose a new design concept for PnCs that examines differently configured double defects for broadband elastic wave energy localization and harvesting. For example, a square-pillar-type unit cell is considered and a defect is considered to be a structure where one piezoelectric patch is bonded to a host square lattice in the absence of a pillar. When the double defects introduced in a PnC are sufficiently distant from each other to implement decoupling behaviors, each defect oscillates like a single independent defect. Here, by differentiating the geometric dimensions of two piezoelectric patches, the defects’ dissimilar equivalent inertia and stiffness contribute to individually manipulating defect bands that correspond to each defect. Hence, with adequately designed piezoelectric patches that consider both the piezoelectric effects on shift patterns of defect bands and the characteristics for the output electric power obtained from a single-defect case, we can successfully localize and harvest the elastic wave energy transferred in broadband frequencies.

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