scholarly journals Analytical Electromechanical Modeling of Nanoscale Flexoelectric Energy Harvesting

2019 ◽  
Vol 9 (11) ◽  
pp. 2273 ◽  
Author(s):  
Yaxuan Su ◽  
Xiaohui Lin ◽  
Rui Huang ◽  
Zhidong Zhou
Keyword(s):  
Energy Harvesting ◽  
Power Density ◽  
Output Power ◽  
Electromechanical Coupling ◽  
Scale Effects ◽  
Dielectric Materials ◽  
Small Scale ◽  
Mechanical Excitation ◽  
Piezoelectric Energy ◽  
Intrinsic Length

With the attention focused on harvesting energy from the ambient environment for nanoscale electronic devices, electromechanical coupling effects in materials have been studied for many potential applications. Flexoelectricity can be observed in all dielectric materials, coupling the strain gradients and polarization, and may lead to strong size-dependent effects at the nanoscale. This paper investigates the flexoelectric energy harvesting under the harmonic mechanical excitation, based on a model similar to the classical Euler–Bernoulli beam theory. The electric Gibbs free energy and the generalized Hamilton’s variational principle for a flexoelectric body are used to derive the coupled governing equations for flexoelectric beams. The closed-form electromechanical expressions are obtained for the steady-state response to the harmonic mechanical excitation in the flexoelectric cantilever beams. The results show that the voltage output, power density, and mechanical vibration response exhibit significant scale effects at the nanoscale. Especially, the output power density for energy harvesting has an optimal value at an intrinsic length scale. This intrinsic length is proportional to the material flexoelectric coefficient. Moreover, it is found that the optimal load resistance for peak power density depends on the beam thickness at the small scale with a critical thickness. Our research indicates that flexoelectric energy harvesting could be a valid alternative to piezoelectric energy harvesting at micro- or nanoscales.

scholarly journals Enhancing Wind Energy Harvesting Using Passive Turbulence Control Devices

2019 ◽  
Vol 9 (5) ◽  
pp. 998 ◽  
Author(s):  
Junlei Wang ◽  
Guoping Li ◽  
Shengxi Zhou ◽  
Grzegorz Litak
Keyword(s):  
Wind Speed ◽  
Energy Harvesting ◽  
Output Power ◽  
Electromechanical Coupling ◽  
Load Resistance ◽  
Turbulence Control ◽  
Critical Wind Speed ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Passive Turbulence Control

Aiming to predict the performance of galloping piezoelectric energy harvesters, a theoretical model is established and verified by experiments. The relative error between the model and experimental results is 5.3%. In addition, the present model is used to study the AC output characteristics of the piezoelectric energy harvesting system under passive turbulence control (PTC), and the influence of load resistance on the critical wind speed, displacement, and output power under both strong and weak coupling are analyzed from the perspective of electromechanical coupling strength, respectively. The results show that the critical wind speed initially increases and then decreases with increasing load resistance. For weak and critical coupling cases, the output power firstly increases and then decreases with the increase of the load resistance, and reaches the maximum value at the optimal load. For the weak, critical, and strong coupling cases, the critical optimal load is 1.1 MΩ, 1.1 MΩ, and 3.0 MΩ, respectively. Overall, the response mechanism of the presented harvester is revealed.

Flexoelectric Energy Harvesting of Circular Rings

2013 ◽  
Author(s):  
X. F. Zhang ◽  
S. D. Hu ◽  
H. S. Tzou
Keyword(s):  
Energy Harvesting ◽  
Output Power ◽  
Strain Gradient ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Design Parameters ◽  
Equivalent Resistance ◽  
Flexoelectric Effect ◽  
Piezoelectric Energy

Flexoelectricity, the electromechanical coupling of the polarization response and strain gradient, occurs in solid crystalline dielectrics of any symmetry or asymmetric crystals. Different from the piezoelectric energy harvester, an energy harvester based on the direct flexoelectric effect is designed in this study. The energy harvester consists of an elastic ring and a flexoelectric patch laminated on its outer surface. Due to the direct flexoelectric effect, the electric energy induced by the strain gradient of the flexoelectric patch is harvested to power the electric device when the ring is subjected to mechanical excitations. Electromechanical coupling equation of the flexoelectric energy harvesting system in close-loop circuit condition is derived. In this study, dynamic response, output power across the external resistor and energy harvesting results are evaluated when the ring is excited by a harmonic point loading. The output power is a function of the external excitation frequency, the external equivalent resistance, the flexoelectric patch’s thickness and other design parameters. Case studies of those parameters for the flexoelectric energy harvester are presented to optimize the output power. Results show that the optimal excitation frequency is equal to the natural frequency for each mode, and the optimal equivalent resistance is dependent of the equivalent capacitance of the flexoelectric patch and the excitation frequency. Since the output power of the flexoelectric energy harvester is similar to that of the piezoelectric energy harvester, comparison of the two harvesters is also discussed. With all the optimal conditions discussed, it can supply a design principle in the engineering applications.

scholarly journals Power Density Improvement of Piezoelectric Energy Harvesters via a Novel Hybridization Scheme with Electromagnetic Transduction

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 803
Author(s):  
Zhongjie Li ◽  
Chuanfu Xin ◽  
Yan Peng ◽  
Min Wang ◽  
Jun Luo ◽  
...  
Keyword(s):  
Power Density ◽  
Output Power ◽  
Energy Harvester ◽  
Hybrid Energy ◽  
Energy Harvesters ◽  
Piezoelectric Patch ◽  
Piezoelectric Energy ◽  
Electromagnetic Transduction ◽  
Self Powered ◽  
Power Densities

A novel hybridization scheme is proposed with electromagnetic transduction to improve the power density of piezoelectric energy harvester (PEH) in this paper. Based on the basic cantilever piezoelectric energy harvester (BC-PEH) composed of a mass block, a piezoelectric patch, and a cantilever beam, we replaced the mass block by a magnet array and added a coil array to form the hybrid energy harvester. To enhance the output power of the electromagnetic energy harvester (EMEH), we utilized an alternating magnet array. Then, to compare the power density of the hybrid harvester and BC-PEH, the experiments of output power were conducted. According to the experimental results, the power densities of the hybrid harvester and BC-PEH are, respectively, 3.53 mW/cm3 and 5.14 μW/cm3 under the conditions of 18.6 Hz and 0.3 g. Therefore, the power density of the hybrid harvester is 686 times as high as that of the BC-PEH, which verified the power density improvement of PEH via a hybridization scheme with EMEH. Additionally, the hybrid harvester exhibits better performance for charging capacitors, such as charging a 2.2 mF capacitor to 8 V within 17 s. It is of great significance to further develop self-powered devices.

scholarly journals Modeling and Experiment of a V-Shaped Piezoelectric Energy Harvester

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Yue Zhao ◽  
Yi Qin ◽  
Lei Guo ◽  
Baoping Tang
Keyword(s):  
Energy Harvesting ◽  
Frequency Band ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Structural Parameters ◽  
Ambient Vibration ◽  
Piezoelectric Bimorph ◽  
Actual Structure ◽  
Piezoelectric Energy ◽  
Operation Frequency

Vibration-based energy harvesting technology is the most promising method to solve the problems of self-powered wireless sensor nodes, but most of the vibration-based energy harvesters have a rather narrow operation bandwidth and the operation frequency band is not convenient to adjust when the ambient frequency changes. Since the ambient vibration may be broadband and changeable, a novel V-shaped vibration energy harvester based on the conventional piezoelectric bimorph cantilevered structure is proposed, which successfully improves the energy harvesting efficiency and provides a way to adjust the operation frequency band of the energy harvester conveniently. The electromechanical coupling equations are established by using Euler-Bernoulli equation and piezoelectric equation, and then the coupled circuit equation is derived based on the series connected piezoelectric cantilevers and Kirchhoff's laws. With the above equations, the output performances of V-shaped structure under different structural parameters and load resistances are simulated and discussed. Finally, by changing the angle θ between two piezoelectric bimorph beams and the load resistance, various comprehensive experiments are carried out to test the performance of this V-shaped energy harvester under the same excitation. The experimental results show that the V-shaped energy harvester can not only improve the frequency response characteristic and the output performance of the electrical energy, but also conveniently tune the operation bandwidth; thus it has great application potential in actual structure health monitoring under variable working condition.

Study of Cantilever Structures Based on Piezoelectric Materials for Energy Harvesting at Low Frequency of Vibration

2014 ◽  
Vol 976 ◽  
pp. 159-163 ◽  
Author(s):  
Roberto Ambrosio ◽  
Hector Gonzalez ◽  
Mario Moreno ◽  
Alfonso Torres ◽  
Rafael Martinez ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Output Power ◽  
Lead Zirconate Titanate ◽  
Maximum Output Power ◽  
Low Frequency ◽  
Electrical Contacts ◽  
Piezoelectric Energy Harvesting ◽  
Maximum Output ◽  
Coupling Coefficients ◽  
Piezoelectric Energy

In this work is presented a study of a piezoelectric energy harvesting device used for low power consumption applications operating at relative low frequency. The structure consists of a cantilever beam made by Lead Zirconate Titanate (PZT) layer with two gold electrodes for electrical contacts. The piezoelectric material was selected taking into account its high coupling coefficients. Different structures were analyzed with variations in its dimensions and shape of the cantilever. The devices were designed to operate at the resonance frequency to get maximum electrical power output. The structures were simulated using finite element (FE) software. The analysis of the harvesting devices was performed in order to investigate the influence of the geometric parameters on the output power and the natural frequency. To validate the simulation results, an experiment with a PZT cantilever with brass substrate was carried out. The experimental data was found to be very close to simulation data. The results indicate that large structures, in the order of millimeters, are the ideal for piezoelectric energy harvesting devices providing a maximum output power in the range of mW

A parametric analysis of the nonlinear dynamics of bistable vibration-based piezoelectric energy harvesters

2020 ◽  
pp. 1045389X2096318
Author(s):  
Luã Guedes Costa ◽  
Luciana Loureiro da Silva Monteiro ◽  
Pedro Manuel Calas Lopes Pacheco ◽  
Marcelo Amorim Savi
Keyword(s):  
Nonlinear Dynamics ◽  
Energy Harvesting ◽  
Parametric Analysis ◽  
Electromechanical Coupling ◽  
Performance Enhancement ◽  
Piezoelectric Materials ◽  
Electrical Power ◽  
Harmonic Excitation ◽  
Piezoelectric Energy ◽  
Harvesting Systems

Piezoelectric materials exhibit electromechanical coupling properties and have been gained importance over the last few decades due to their broad range of applications. Vibration-based energy harvesting systems have been proposed using the direct piezoelectric effect by converting mechanical into electrical energy. Although the great relevance of these systems, performance enhancement strategies are essential to improve the applicability of these system and have been studied substantially. This work addresses a numerical investigation of the influence of cubic polynomial nonlinearities in energy harvesting systems considering a bistable structure subjected to harmonic excitation. A deep parametric analysis is carried out employing nonlinear dynamics tools. Results show complex dynamical behaviors associated with the trigger of inter-well motion. Electrical power output and efficiency are monitored in order to evaluate the configurations associated with best system performances.

Study of an Impact Driven Frequency Up-Conversion Piezoelectric Harvester

2017 ◽  
Author(s):  
Amin Abedini ◽  
Saeed Onsorynezhad ◽  
Fengxia Wang
Keyword(s):  
Energy Harvesting ◽  
Output Power ◽  
Power Efficiency ◽  
Constitutive Law ◽  
Flexible Beam ◽  
Nonlinear Phenomena ◽  
Base Excitation ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam ◽  
The Impact

Frequency up-conversion is an effective way to increase the output power from a piezoelectric beam, which converts the ambient low-frequency vibration to the resonant vibration of the piezoelectric energy harvesters (PEH) to achieve high electric power output. Frequency up-conversion technologies are realized via impact or non-impact magnetic force to mediate the interaction between the driving beam and the generating beam. Most studies focus on the either linear model prediction or experimental verification of the linear analysis. Few, if any, study the effects of the impact induced nonlinear phenomena on power generation efficiency. In this work, we investigate how to use discontinuous theory to improve the power efficiency of the frequency up-conversion process caused by impacts. The energy harvesting performance of a piezoelectric beam in interaction with a softer beam in periodic motion is studied. The discontinuous dynamical system theory is applied to this problem to study the piezoelectric behavior under periodic motions and its bifurcations. The beams are modeled with two spring-mass-damper systems, and the analytical model of the piezoelectric beam is created based on the linear mechanical-electrical constitutive law of the piezoelectric material, and the linear elastic constitutive law of the substrate. Based on the theoretical model, the analytical solution of the output power is derived in terms of the vibration amplitude, frequency, and the electrical load. The soft beam is subjected to a sinusoidal base excitation, and the impacts of the more flexible beam excite the piezoelectric beam. The performance of the energy harvesting of period one and period two motions have been studied and bifurcation trees for impact velocities, times, displacements and harvested power versus the frequency of the base excitation are obtained.

Modeling and Analysis of Piezoelectric Energy Harvesting From Aeroelastic Vibrations Using the Doublet-Lattice Method

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Carlos De Marqui ◽  
Wander G. R. Vieira ◽  
Alper Erturk ◽  
Daniel J. Inman
Keyword(s):  
Energy Source ◽  
Energy Harvesting ◽  
Frequency Domain ◽  
Electromechanical Coupling ◽  
Lattice Method ◽  
Modeling And Analysis ◽  
Piezoelectric Energy ◽  
Doublet Lattice Method ◽  
Aeroelastic Vibrations ◽  
Air Vehicles

Multifunctional structures are pointed out as an important technology for the design of aircraft with volume, mass, and energy source limitations such as unmanned air vehicles (UAVs) and micro air vehicles (MAVs). In addition to its primary function of bearing aerodynamic loads, the wing/spar structure of an UAV or a MAV with embedded piezoceramics can provide an extra electrical energy source based on the concept of vibration energy harvesting to power small and wireless electronic components. Aeroelastic vibrations of a lifting surface can be converted into electricity using piezoelectric transduction. In this paper, frequency-domain piezoaeroelastic modeling and analysis of a cantilevered platelike wing with embedded piezoceramics is presented for energy harvesting. The electromechanical finite-element plate model is based on the thin-plate (Kirchhoff) assumptions while the unsteady aerodynamic model uses the doublet-lattice method. The electromechanical and aerodynamic models are combined to obtain the piezoaeroelastic equations, which are solved using a p-k scheme that accounts for the electromechanical coupling. The evolution of the aerodynamic damping and the frequency of each mode are obtained with changing airflow speed for a given electrical circuit. Expressions for piezoaeroelastically coupled frequency response functions (voltage, current, and electrical power as well the vibratory motion) are also defined by combining flow excitation with harmonic base excitation. Hence, piezoaeroelastic evolution can be investigated in frequency domain for different airflow speeds and electrical boundary conditions.

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