scholarly journals Highly Localized and Efficient Energy Harvesting in a Phononic Crystal Beam: Defect Placement and Experimental Validation

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 391 ◽  
Author(s):  
Xu-Feng Lv ◽  
Xiang Fang ◽  
Zhi-Qiang Zhang ◽  
Zhi-Long Huang ◽  
Kuo-Chih Chuang

We study energy harvesting in a binary phononic crystal (PC) beam at the defect mode. Specifically, we consider the placement of a mismatched unit cell related to the excitation point. The mismatched unit cell contains a perfect segment and a geometrically mismatched one with a lower flexural rigidity which serves as a point defect. We show that the strain in the defect PC beam is much larger than those in homogeneous beams with a defect segment. We suggest that the defect segment should be arranged in the first unit cell, but not directly connected to the excitation source, to achieve efficient less-attenuated localized energy harvesting. To harvest the energy, a polyvinylidene fluoride (PVDF) film is attached on top of the mismatched segment. Our numerical and experimental results indicate that the placement of the mismatched segment, which has not been addressed for PC beams under mechanical excitation, plays an important role in efficient energy harvesting based on the defect mode.

Author(s):  
Xian’e Yang ◽  
Jiahui Zhong ◽  
Jiawei Xiang

Abstract Phononic crystal (PnC) has been proved for its manipulation and amplification of elastic waves. Using this characteristic of PnC to assist energy harvesting has remarkable effect. Generally, defect occurs when unit cell in PnC is replaced by another cell with different geometric or material properties, the output electric power of piezoelectric energy harvesting (PEH) devices will be significantly enhanced. In this study, a cross hole-type PnC-assisted PEH device with a large-size defect is presented by replacing several adjacent multiple cells with other cells. It is found that multiple peak voltages can be created within BG and multimodal energy harvesting can be performed. Compared with the defect mode composed of a small-size defect, energy localization and amplification of the proposed PnC leads to substantially enhancement of harvesting power after tailoring geometric parameters of a PEH device. This work will be expected to design PnC-assisted PEH devices in a reasonable way.


2019 ◽  
Author(s):  
Mohammadsadegh Saadatzi ◽  
Mohammad Nasser Saadatzi ◽  
Sourav Banerjee

Abstract In the current study, a novel multi-frequency, vibration-based Energy Harvester (EH) is proposed, numerically verified, and experimentally validated. The structural design of the proposed EH is inspired from an inner-ear, snail-shaped structure. In the past decade, scavenging power from environmental sources of vibration has attracted a lot of researchers to the field of energy harvesting. High demands for cleaner and renewable energy sources, limited sources of electrical energy, high depletion rates of nonrenewable sources of energy, and environmental concerns have urged researchers to investigate new structures called Metamaterial energy harvesters to harness electrical potential. The proposed EH is a metamaterial structure which has a Polyvinylidene Difluoride (PVDF) structure incapsulated in an aluminum frame and follows the physics of a mass-in-mass Phononic crystal structure. The PVDF snail-shaped structure is encapsulated inside a silicone matrix with a specific material property. This EH reacts to the environmental vibrations and the encapsulating silicone entraps the kinetic energy within its structure. The EH unit cell behaves as a negative mass in the vicinity of its resonance frequencies. In this paper, the dynamic behavior of the proposed EH is numerically modeled in COMSOL Multiphysics and, subsequently, validated experimentally using a unit cell fabricated in-house.


2013 ◽  
Vol 102 (3) ◽  
pp. 034103 ◽  
Author(s):  
Hangyuan Lv ◽  
Xiaoyong Tian ◽  
Michael Yu Wang ◽  
Dichen Li

2010 ◽  
Vol 150-151 ◽  
pp. 1282-1285
Author(s):  
Zong Jian Yao ◽  
Gui Lan Yu ◽  
Yue Sheng Wang ◽  
Jian Bao Li

The improved supercell plane wave expansion method is applied to theoretically study the propagation of flexural waves in a ternary locally resonant phononic crystal thin plate with a point defect and linear defects. The thin concrete plate composed of a square array of steel cylinders hemmed around by rubber is considered here. Absolute band gaps in low frequency are obtained. For the point defect, the defect mode is localized around the defect, and the magnitude of the resonant defect mode is strongly dependent on the defect filling fraction, mass density and Young’s modulus of the defect cylinder. For the straight linear defects, several resonant linear defect bands appear inside the absolute band gap. And the displacement distributions show that the flexural waves could well propagate along the linear defects.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 284
Author(s):  
Chen Han ◽  
Renbin Zhong ◽  
Zekun Liang ◽  
Long Yang ◽  
Zheng Fang ◽  
...  

This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 585
Author(s):  
Ariel Ma ◽  
Jian Yu ◽  
William Uspal

Natural evaporation has recently come under consideration as a viable source of renewable energy. Demonstrations of the validity of the concept have been reported for devices incorporating carbon-based nanocomposite materials. In this study, we investigated the possibility of using polymer thin films to generate electricity from natural evaporation. We considered a polymeric system based on polyvinylidene fluoride (PVDF). Porous PVDF films were created by incorporating a variety of nanocomposite materials into the polymer structure through a simple mixing procedure. Three nanocomposite materials were considered: carbon nanotubes, graphene oxide, and silica. The evaporation-induced electricity generation was confirmed experimentally under various ambient conditions. Among the nanocomposite materials considered, mesoporous silica (SBA-15) was found to outperform the other two materials in terms of open-circuit voltage, and graphene oxide generated the highest short-circuit current. It was found that the nanocomposite material content in the PVDF film plays an important role: on the one hand, if particles are too few in number, the number of channels will be insufficient to support a strong capillary flow; on the other hand, an excessive number of particles will suppress the flow due to excessive water absorption underneath the surface. We show that the device can be modeled as a simple circuit powered by a current source with excellent agreement between the theoretical predictions and experimental data.


2021 ◽  
Vol 287 ◽  
pp. 129271
Author(s):  
Shengnan Zhang ◽  
Jianming Xu ◽  
Junbin Yu ◽  
Linlin Song ◽  
Jian He ◽  
...  

Author(s):  
Chunlang Gao ◽  
Chunqiang Zhuang ◽  
Yuanli Li ◽  
Heyang Qi ◽  
Ge Chen ◽  
...  

In this study, we employed in-situ liquid cell transmission electron microscopy (LC-TEM) to carry out the new design strategy of precisely regulating the microstructure of large-sized cocatalysts for highly efficient...


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