Flexoelectric energy harvesters based on Timoshenko laminated beam theory

2017 ◽  
Vol 28 (15) ◽  
pp. 2064-2073 ◽  
Author(s):  
Xu Liang ◽  
Runzhi Zhang ◽  
Shuling Hu ◽  
Shengping Shen
Keyword(s):  
Resonance Frequency ◽  
Energy Conversion ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Mechanical Vibration ◽  
Beam Theory ◽  
Electrical Energy ◽  
Laminated Beam ◽  
Energy Harvesters

Different from piezoelectricity which is restricted to certain materials, flexoelectricity is a universal electromechanical coupling in all dielectrics. In this work, mechanical energy harvester models were developed based on Timoshenko laminated beam theory, in which the flexoelectric and piezoelectric mechanisms were discussed. For a three-layered energy harvester in parallel configuration, the mechanical vibration energy can be converted into electrical energy due to flexoelectricity, and for the three-layered energy harvester in series configuration, the energy conversion is enhanced by the flexoelectricity. Resonance frequency shifts were observed in the calculations due to flexoelectricity and external circuit resistance. It is found that the electromechanical coupling displayed from the electrical responses versus resonance frequency and resistance. The energy conversion for the three-layered energy harvester system was found to be increased with the decrease in the laminated beam thickness. The energy conversion calculated for different numbers of layers also indicates that laminated energy harvester systems excel single-layered energy harvesters. This work therefore might help in designing flexoelectricity-based energy harvesters.

scholarly journals Properties of Car-Embedded Vibrating Type Piezoelectric Harvesting System

2021 ◽  
Vol 11 (16) ◽  
pp. 7449
Author(s):  
Bo-Gun Koo ◽  
Dong-Jin Shin ◽  
Dong-Hwan Lim ◽  
Min-Soo Kim ◽  
In-Sung Kim ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Energy Conversion ◽  
Mechanical Energy ◽  
Variable Mass ◽  
Electrical Energy ◽  
Engine Block ◽  
Operating Frequency ◽  
Maximum Displacement ◽  
Serial Connection ◽  
Piezoelectric Generator

We investigated the harvesting performance of a double piezoelectric generator, which was embedded into the engine block of a small passenger car. The resonance frequency is approximately between 37 and 52 Hz, where the cantilever showed maximum displacement. In reality, the cantilever has a vibrating characteristic, which dramatically reduces displacement, even when the operating frequency deviates slightly from the resonance frequency. To acquire a large mechanical energy-to-electrical energy conversion, a multiple-piezoelectric generator was employed to absorb the energy even when the vibration switched from a resonance to a non-resonance frequency. In this study, a variable mass box was designed and installed in the engine block of a car. The variable mass box consisted of the serial connection of two masses with different weights. The operating frequency deviated from a resonance to a non-resonance frequency within a few hertz (3~4 Hz); the reduction in vibration was lower, leading to a significant acquisition of the resulting power. This is due to the variable matching of the generator, realized by the action of dual mass. This type of generator was installed in the engine block and produced up to 0.038 and 0.357 mW when the engine was operating at 2200 and 3200 rpm, respectively.

scholarly journals Development and Validation of an Enhanced Coupled-Field Model for PZT Cantilever Bimorph Energy Harvester

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Long Zhang ◽  
Keith A. Williams ◽  
Zhengchao Xie
Keyword(s):  
Energy Harvester ◽  
Field Model ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Open Circuit ◽  
Conservation Of Energy ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Comparison Results ◽  
Coupled Field

The power source with the limited life span has motivated the development of the energy harvesters that can scavenge the ambient environment energy and convert it into the electrical energy. With the coupled field characteristics of structure to electricity, piezoelectric energy harvesters are under consideration as a means of converting the mechanical energy to the electrical energy, with the goal of realizing completely self-powered sensor systems. In this paper, two previous models in the literatures for predicting the open-circuit and close-circuit voltages of a piezoelectric cantilever bimorph (PCB) energy harvester are first described, that is, the mechanical equivalent spring mass-damper model and the electrical equivalent circuit model. Then, the development of an enhanced coupled field model for the PCB energy harvester based on another previous model in the literature using a conservation of energy method is presented. Further, the laboratory experiments are carried out to evaluate the enhanced coupled field model and the other two previous models in the literatures. The comparison results show that the enhanced coupled field model can better predict the open-circuit and close-circuit voltages of the PCB energy harvester with a proof mass bonded at the free end of the structure in order to increase the energy-harvesting level of the system.

Key Issues on Flextensional Piezoelectric Energy Harvester Developments

2019 ◽  
Author(s):  
Tian-Bing Xu ◽  
Lei Zuo
Keyword(s):  
Dipole Moment ◽  
Energy Storage ◽  
Energy Conversion ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Storage Efficiency ◽  
Energy Storage Efficiency

Abstract A “33” mode (mechanical stress being in parallel to the electric dipole moment direction) piezoelectric lead zirconate titanate (PZT) multilayer stack-based piezoelectric flextensional energy harvester (PZT-Stacked-FEH) has been developed. Interdisciplinary approaches had been taken to increase the performance of the PZT-Stacked-FEH. First, an elastic flextensional frame for force amplification has been optimally designed to capture more mechanical energy with high energy transition efficiency into the PZT-Stacked-FEH. Second, a “33” mode piezoelectric PZT multilayer stack (PZT-Stack) was employed instead of “31” mode (stress being in perpendicular to the dipole moment direction) single layer piezoelectric component to increase mechanical to electrical energy conversion efficiency and to generate more electrical charges in order to improve energy storage efficiency. With these approaches, the PZT-Stacked-FEH demonstrates excellent performance: 1) a 19% of overall mechanical to electrical energy conversion efficiency was achieved, 2) 48.6 times more mechanical energy was transited into PZT-Stacked-FEH and 26.5 times more electrical power was generated than directly applying force to the PZT-stack, and 3) energy storage efficiency was significantly improved. In this paper, we are focusing on the investigations for the off-resonance mode performance of the PZT-Stacked-FEH through theoretical modeling, prototype development, and experimental studies. A prototype PZT-Stacked-FEH of weight 18 grams was able to generate 666 mW electrical power under 52 Nrms force at 250 Hz, which is much lower than the resonant frequency (936 Hz). At this condition, a 6,600 μF super-capacitor was charged from 0 to 7 V in 1.6 second, at an average rate of 100 mW. Furthermore, 70% of generated appear electrical powers were delivered to matched resistive loads in the investigated regime of frequencies. Finally, the experimental results matched well with theoretical predictions which verified the developed theoretical models.

High-output piezoelectric energy harvester using tapered beam with cavity

2017 ◽  
Vol 29 (5) ◽  
pp. 800-815 ◽  
Author(s):  
S Srinivasulu Raju ◽  
M Umapathy ◽  
G Uma
Keyword(s):  
Analytical Model ◽  
Cantilever Beam ◽  
Energy Harvester ◽  
Structural Parameters ◽  
Beam Theory ◽  
Electrical Energy ◽  
Tapered Beam ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Structure

Energy harvesting using cantilever-based piezoelectric structure is most popular for harvesting electrical energy from ambient vibrations. Efforts are also made to maximize the harvester power by means of tailoring the structural parameters of the cantilever beam. This article proposes a method to maximize the harvester voltage from the cantilever-based piezoelectric energy harvester by means of tailoring the structure of the cantilever, to have a tapering in width, thickness and in both width and thickness (double taper). It is also proposed to introduce rectangular and trapezoidal cavities in the tapered energy harvesters to further maximize the harvester voltage. The analytical model of the proposed harvesters is developed using Euler–Bernoulli beam theory, and its free vibration solution is analysed using Bessel functions. The energy harvesters are fabricated and experimentally evaluated for its performance. It is concluded from the results of analytical model and experimentation that width, thickness and double-tapered beam increases the harvester voltage by 35.6%, 84.8% and 126.6%, respectively, as compared to the energy harvester designed with uniform cantilever beam. Among all the energy harvesters proposed in this article, the maximum voltage is generated from the double-tapered beam with trapezoidal cavity. The experimental results are in close agreement with the results obtained from the analytical model.

A Novel Piezoelectric Multilayer Stack Energy Harvester With Force Amplification

2013 ◽  
Author(s):  
Wanlu Zhou ◽  
Lei Zuo
Keyword(s):  
Energy Conversion ◽  
Energy Harvester ◽  
Proof Mass ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Power Delivery ◽  
Delivery Ratio ◽  
Resistive Load

A piezoelectric lead zirconate titanate (PZT) multilayer stack flextensional energy harvester (PZT-Stack-FEH) was designed and characterized in this paper. An elastic flextensional frame for force amplification was optimally designed to transmit more mechanical energy with high efficiency to the PZT-Stack-FEH. Instead of 31-mode single layer piezoelectric component, a 33-mode piezoelectric PZT multilayer stack was employed to increase mechanical-to-electrical energy conversion efficiency. The power delivery ratio of the electrical power dissipated by resistive load over the total generated electrical power from PZT stack was studied. Theoretical analysis and experiments were carried out. The experiment results show that the mechanical-to-electrical energy conversion efficiency of the PZT-Stack-FEH is 19%, 48.6 times more mechanical energy can be transmitted to PZT-Stack-FEH, and 26.5 times more electrical energy can be generated by using the PZT-Stack-FEH than directly applying force to the PZT multilayer stack. The maximum power delivery ratio can attain 70% when the resistive load matches the impedance of piezoelectric stack. The power generation performance of the PZT-Stack-FEH with a proof mass was also studied. Experiment results show that he peak power/acceleration can attain 2400mW/g when the PZT-Stack-FEH is connected with a proof mass of 200 grams and 3280 mW/g with a proof mass of 500 grams.

Modulated Magneto-Thermal Response of La0.85Sr0.15MnO3 and (Ni0.6Cu0.2Zn0.2)Fe2O4 Composites for Thermal Energy Harvesters

2019 ◽  
Vol 4 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Hyun-Cheol Song ◽  
Deepam Maurya ◽  
Jinsung Chun ◽  
Yuan Zhou ◽  
Myung-Eun Song ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Mechanical Energy ◽  
Thermal Response ◽  
Electrical Energy ◽  
Soft Magnetic ◽  
Efficient Operation ◽  
Energy Harvesters ◽  
Operational Frequency

Abstract The magneto-thermoelectric generator (MTG) converts wasted thermal energy into electrical energy in two steps. The first step involves thermal to mechanical energy conversion through balance of magnetic and elastic forces and the second step involves mechanical to electrical energy conversion through piezoelectric effect. The requirements for soft magnetic material in improving the efficiency of first step were identified and met through the design of a composite architecture. The Curie temperature of La(1–x)SrxMnO3 can be engineered to be near room temperature by modifying the Sr content. Composite of La0.85Sr0.15MnO3 (LSMO) and Ni0.6Cu0.2Zn0.2Fe2O4 (NCZF) was found to exhibit high saturation (Ms) and remnant (Mr) magnetization magnitude while maintaining the soft magnetic nature. Two-step sintering was found to prevent the inter-diffusion of LSMO and NCZF phases and provided high density without grain growth. The LSMO-NCZF (70:30 wt%) composite exhibited a large variation in Ms with respect to the change in temperature near Curie temperature which meets the requirements for efficient operation of MTG. The fabricated MTG using LSMO-NCZF (70:30 wt%) composite reached 0.2 Hz operational frequency and generated electrical output voltage of 2 Vp–p and peak power of 17 µW under the thermal gradient of 80 °C (0 °C/80 °C).

Enhanced Coupled Field Modeling of PZT Cantilever Bimorph Energy Harvester

2011 ◽  
Vol 145 ◽  
pp. 21-26
Author(s):  
Long Zhang ◽  
Keith A. Williams ◽  
Zheng Chao Xie
Keyword(s):  
Energy Harvester ◽  
Field Model ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Consumer Electronics ◽  
Conservation Of Energy ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Comparison Results ◽  
Coupled Field

As consumer electronics continue to develop in size and scope, the battery power source with the limited life span poses an increasing economic challenge. This growing problem has motivated the development of the energy harvesters that can scavenge the ambient environment energy and convert it into the electrical energy for use of the wireless sensor nodes and the portable electronics. With the coupled field characteristics of structure to electricity, piezoelectric energy harvesters are under consideration as a means for converting the mechanical energy to the electrical energy, with the goal of realizing completely self-powered sensor systems. In this paper, the development of an enhanced coupled field model for the PCB energy harvester based on a previous model in the literature using a conservation of energy method is presented. Further, the laboratory experiments are carried out to evaluate the enhanced coupled field model and the other two previous models in the literatures. The comparison results show that the enhanced coupled field model can better predict the open-circuit of the PCB energy harvester with a proof mass bonded at the free end of the structure in order to increase the energy harvesting level of the system.

Enhanced frequency synchronization for concurrent aeroelastic and base vibratory energy harvesting using a softening nonlinear galloping energy harvester

2021 ◽  
pp. 1045389X2110263
Author(s):  
Shun Chen ◽  
David Eager ◽  
Liya Zhao
Keyword(s):  
Energy Harvesting ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Poor Performance ◽  
Effective Bandwidth ◽  
Frequency Synchronization ◽  
Periodic Oscillations ◽  
Energy Harvesters ◽  
Paper Form ◽  
Excited Oscillation

This paper proposes a softening nonlinear aeroelastic galloping energy harvester for enhanced energy harvesting from concurrent wind flow and base vibration. Traditional linear aeroelastic energy harvesters have poor performance with quasi-periodic oscillations when the base vibration frequency deviates from the aeroelastic frequency. The softening nonlinearity in the proposed harvester alters the self-excited galloping frequency and simultaneously extends the large-amplitude base-excited oscillation to a wider frequency range, achieving frequency synchronization over a remarkably broadened bandwidth with periodic oscillations for efficient energy conversion from dual sources. A fully coupled aero-electro-mechanical model is built and validated with measurements on a devised prototype. At a wind speed of 5.5 m/s and base acceleration of 0.1 g, the proposed harvester improves the performance by widening the effective bandwidth by 300% compared to the linear counterpart without sacrificing the voltage level. The influences of nonlinearity configuration, excitation magnitude, and electromechanical coupling strength on the mechanical and electrical behavior are examined. The results of this paper form a baseline for future efficiency enhancement of energy harvesting from concurrent wind and base vibration utilizing monostable stiffness nonlinearities.

scholarly journals Fluorinated Polyethylene Propylene Ferroelectrets with an Air-Filled Concentric Tunnel Structure: Preparation, Characterization, and Application in Energy Harvesting

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1072
Author(s):  
Xi Zuo ◽  
Li Chen ◽  
Wenjun Pan ◽  
Xingchen Ma ◽  
Tongqing Yang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Resonance Frequency ◽  
Power Output ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Piezoelectric Response ◽  
Tunnel Structure ◽  
Energy Harvesters ◽  
The Earth ◽  
Seismic Mass

Fluorinated polyethylene propylene (FEP) bipolar ferroelectret films with a specifically designed concentric tunnel structure were prepared by means of rigid-template based thermoplastic molding and contact polarization. The properties of the fabricated films, including the piezoelectric response, mechanical property, and thermal stability, were characterized, and two kinds of energy harvesters based on such ferroelectret films, working in 33- and 31-modes respectively, were investigated. The results show that the FEP films exhibit significant longitudinal and radial piezoelectric activities, as well as superior thermal stability. A quasi-static piezoelectric d33 coefficient of up to 5300 pC/N was achieved for the FEP films, and a radial piezoelectric sensitivity of 40,000 pC/N was obtained in a circular film sample with a diameter of 30 mm. Such films were thermally stable at 120 °C after a reduction of 35%. Two types of vibrational energy harvesters working in 33-mode and 31-mode were subsequently designed. The results show that a power output of up to 1 mW was achieved in an energy harvester working in 33-mode at a resonance frequency of 210 Hz, referring to a seismic mass of 33.4 g and an acceleration of 1 g (g is the gravity of the earth). For a device working in 31-mode, a power output of 15 μW was obtained at a relatively low resonance frequency of 26 Hz and a light seismic mass of 1.9 g. Therefore, such concentric tunnel FEP ferroelectric films provide flexible options for designing vibrational energy harvesters working either in 33-mode or 31-mode to adapt to application environments.

Resonant Frequency Tuning Strategies for Vibration-Based Energy Harvesters

2017 ◽  
Author(s):  
Lin Dong ◽  
Frank T. Fisher
Keyword(s):  
Energy Harvesting ◽  
Resonant Frequency ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Electrical Energy ◽  
Mechanical Stretch ◽  
Applied Bias Voltage ◽  
Energy Harvesters ◽  
Frequency Matching ◽  
Low Levels

Vibration-based energy harvesting has been widely investigated to as a means to generate low levels of electrical energy for applications such as wireless sensor networks. However, due to the fact that vibration from the environment is typically random and varies with different magnitudes and frequencies, it is a challenge to implement frequency matching in order to maximize the power output of the energy harvester with a wider frequency bandwidth for applications where there is a time-dependent, varying source frequency. Possible solutions of frequency matching include widening the bandwidth of the energy harvesters themselves in order to implement frequency matching and to perform resonance-based tuning approach, the latter of which shows the most promise to implement a frequency matching design. Here three tuning strategies are discussed. First a two-dimensional resonant frequency tuning technique for the cantilever-geometry energy harvesting device which extended previous 1D tuning approaches was developed. This 2D approach could be used in applications where space constraints impact the available design space of the energy harvester. In addition, two novel resonant frequency tuning approaches (tuning via mechanical stretch and tuning via applied bias voltage, respectively) for electroactive polymer (EAP) membrane-based geometry energy harvesters was proposed, such that the resulting changes in membrane tension were used to tune the device for applications targeting variable ambient frequency environments.

Sign in / Sign up

Export Citation Format

Share Document