Exploiting Super-Harmonic Resonances of a Bi-Stable Axially-Loaded Beam for Energy Harvesting Under Low-Frequency Excitations

Author(s):  
Ravindra Masana ◽  
Mohammed F. Daqaq

A research paradox currently lies in the design of miniaturized vibratory energy harvesters capable of harnessing energy efficiently from low-frequency excitations. To address this problem, this effort investigates the prospect of utilizing super-harmonic resonances of a bi-stable system to harvest energy from excitation sources with low-frequency components. Towards that objective, the paper considers the electromechanical response of an axially-loaded clamped-clamped piezoelectric beam harvester with bi-stable potential characteristics. By numerically constructing the voltage-frequency bifurcation maps of the response near the super-harmonic resonance of order two, it is shown that, for certain base excitation levels, the harvester can exhibit responses that are favorable for energy harvesting. These include a unique branch of large-orbit periodic inter-well oscillations, coexisting branches of large-orbit solutions, and a bandwidth of frequencies where a unique chaotic attractor exists. In these regions, the harvester can produce power levels that are comparable to those obtained near the primary resonance.

Author(s):  
M. H. Ansari ◽  
M. Amin Karami

A three dimensional piezoelectric vibration energy harvester is designed to generate electricity from heartbeat vibrations. The device consists of several bimorph piezoelectric beams stacked on top of each other. These horizontal bimorph beams are connected to each other by rigid vertical beams making a fan-folded geometry. One end of the design is clamped and the other end is free. One major problem in micro-scale piezoelectric energy harvesters is their high natural frequency. The same challenge is faced in development of a compact vibration energy harvester for the low frequency heartbeat vibrations. One way to decrease the natural frequency is to increase the length of the bimorph beam. This approach is not usually practical due to size limitations. By utilizing the fan-folded geometry, the natural frequency is decreased while the size constraints are observed. The required size limit of the energy harvester is 1 cm by 1 cm by 1 cm. In this paper, the natural frequencies and mode shapes of fan-folded energy harvesters are analytically derived. The electro-mechanical coupling has been included in the model for the piezoelectric beam. The design criteria for the device are discussed.


Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 845 ◽  
Author(s):  
Abdolreza Pasharavesh ◽  
Reza Moheimani ◽  
Hamid Dalir

The deliberate introduction of nonlinearities is widely used as an effective technique for the bandwidth broadening of conventional linear energy harvesting devices. This approach not only results in a more uniform behavior of the output power within a wider frequency band through bending the resonance response, but also contributes to energy harvesting from low-frequency excitations by activation of superharmonic resonances. This article investigates the nonlinear dynamics of a monostable piezoelectric harvester under a self-powered electromagnetic actuation. To this end, the governing nonlinear partial differential equations of the proposed harvester are order-reduced and solved by means of the perturbation method of multiple scales. The results indicate that, according to the excitation amplitude and load resistance, different responses can be distinguished at the primary resonance. The system behavior may involve the traditional bending of response curves, Hopf bifurcations, and instability regions. Furthermore, an order-two superharmonic resonance is observed, which is activated at lower excitations in comparison to order-three conventional resonances of the Duffing-type resonator. This secondary resonance makes it possible to extract considerable amounts of power at fractions of natural frequency, which is very beneficial in micro-electro-mechanical systems (MEMS)-based harvesters with generally high resonance frequencies. The extracted power in both primary and superharmonic resonances are analytically calculated, then verified by a numerical solution where a good agreement is observed between the results.


2019 ◽  
Vol 29 (10) ◽  
pp. 1930029 ◽  
Author(s):  
Amin Abedini ◽  
Saeed Onsorynezhad ◽  
Fengxia Wang

Frequency up-conversion has been proved to be an effective approach to increase the output power of a piezoelectric energy harvester (PEH). The proposed system can convert low-frequency vibration from ambient sources to the resonant vibration of the PEH hence can improve the output power efficiency. Frequency up-conversion technologies are introduced via impact or nonimpact magnetic forces to initiate the repeated free oscillations of the piezoelectric generator. No matter impact- or nonimpact-driven PEHs, most studies focus on either finite element simulation or experimental demonstration of PEHs electric power generations. Few, if any, study the effects of the impact-induced discontinuous dynamics on power generation efficiency. In this work, the energy harvesting performance of a piezoelectric beam upon interaction with a softer driving beam was studied. The discontinuous dynamics behind this impact-driven PEH was investigated, and strategies exploited to further improve the power efficiency of the frequency up-conversion process. Based on the linear elastic and linear mechanical-electrical constitutive laws, the lumped parameter models were built for both the driving beam and the piezoelectric driven beam. The numerical solution of the output power is obtained based on the vibration amplitude, frequency, and the electrical load. The soft beam is subjected to a sinusoidal base excitation, and the piezoelectric beam was excited via impacting with the soft driving beam. Based on the discontinuous dynamics theory, the performance of the energy harvesting of the impact-driven system was studied for period-1 and period-2 motions. Based on the stability and bifurcation analysis of periodic solutions, bifurcation diagrams of impact velocities, times, displacements and harvested power versus the frequency of the base excitation were also obtained, and compared to the power generation of a piezoelectric beam with base excitation.


2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Xinlei Fu ◽  
Wei-Hsin Liao

Nonharmonic excitations are widely distributed in the environment. They can work as energy sources of vibration energy harvesters for powering wireless electronics. To overcome the narrow bandwidth of linear vibration energy harvesters, plucking piezoelectric energy harvesters have been designed. Plucking piezoelectric energy harvesters can convert sporadic motions into plucking force to excite vibration energy harvesters and achieve broadband performances. Though different kinds of plucking piezoelectric energy harvesters have been designed, the plucking mechanism is not well understood. The simplified models of plucking piezoelectric energy harvesting neglect the dynamic interaction between the plectrum and the piezoelectric beam. This research work is aimed at investigating the plucking mechanism and developing a comprehensive model of plucking piezoelectric energy harvesting. In this paper, the dynamic plucking mechanism is investigated and the Hertzian contact theory is applied. The developed model of plucking piezoelectric energy harvesting accounts for the dynamic interaction between the plectrum and the piezoelectric beam by considering contact theory. Experimental results show that the developed model well predicts the responses of plucking piezoelectric energy harvesters under different plucking velocities and overlap lengths. Parametric studies are conducted on the dimensionless model after choosing appropriate scaling. The influences of plucking velocity and overlap length on energy harvesting performance and energy conversion efficiency are discussed. The comprehensive model helps investigate the characteristics and guide the design of plucking piezoelectric energy harvesters.


Author(s):  
Aneesh Koka ◽  
Henry A. Sodano

Piezoelectric nanowires (NWs) have recently attracted immense interest due to their excellent electro-mechanical coupling behavior that can efficiently enable conversion of low-intensity mechanical vibrations for powering or augmenting batteries of biomedical devices and portable consumer electronics. Specifically, nano-electromechanical systems (NEMS) composed of piezoelectric NWs offer an exciting potential for energy harvesting applications due to their enhanced flexibility, light weight, and compact size. Compared to the bulk form, high aspect ratio NWs can exhibit higher deformation to produce an enhanced piezoelectric response at a lower stress level. NEMS made of conventional semiconducting vertically aligned, ZnO NW arrays have been investigated thoroughly for energy harvesting; however, ZnO has a lower piezoelectric coupling coefficient as compared to many ferroelectric ceramics which limits its piezoelectric performance. Amidst lead-free ferroelectric materials, environmentally-friendly barium titanate (BaTiO3) possesses one of the highest piezoelectric strain coefficients and thus can enable greater energy transfer when used in vibrational energy harvesters. In this paper, a novel NEMS energy harvester is fabricated using ultra-long (∼40 μm long), vertically aligned BaTiO3 NW arrays which has a low resonant frequency (below 200 Hz) and its AC power harvesting capacity from low amplitude base vibrations (0.25 g) is demonstrated. The design and fabrication of low resonant frequency vibrational energy harvesters has been challenging in the field of MEMS/NEMS since the high stiffness of the structures results in resonant frequency often greater than 1 kHz. However, ambient mechanical vibrations usually exist in the 1 Hz to 1 kHz range and thus highly complaint ultra-long, NW arrays are beneficial to enable efficient energy conversion. Through the use of this newly developed synthesis process for the growth of highly compliant, ultra-long BaTiO3 NW arrays, it is shown that piezoelectric NWs based NEMS energy harvesters capable of harnessing this low frequency ambient vibrational energy can be conceived.


2012 ◽  
Vol 23 (13) ◽  
pp. 1433-1449 ◽  
Author(s):  
Lihua Tang ◽  
Yaowen Yang ◽  
Chee-Kiong Soh

In recent years, several strategies have been proposed to improve the functionality of energy harvesters under broadband vibrations, but they only improve the efficiency of energy harvesting under limited conditions. In this work, a comprehensive experimental study is conducted to investigate the use of magnets for improving the functionality of energy harvesters under various vibration scenarios. First, the nonlinearities introduced by magnets are exploited to improve the performance of vibration energy harvesting. Both monostable and bistable configurations are investigated under sinusoidal and random vibrations with various excitation levels. The optimal nonlinear configuration (in terms of distance between magnets) is determined to be near the monostable-to-bistable transition region. Results show that both monostable and bistable nonlinear configurations can significantly outperform the linear harvester near this transition region. Second, for ultra-low-frequency vibration scenarios such as wave heave motions, a frequency up-conversion mechanism using magnets is proposed. By parametric study, the repulsive configuration of magnets is found preferable in the frequency up-conversion technique, which is efficient and insensitive to various wave conditions when the magnets are placed sufficiently close. These findings could serve as useful design guidelines when nonlinearity or frequency up-conversion techniques are employed to improve the functionality of vibration energy harvesters.


Author(s):  
Christopher Sugino ◽  
Vinciane Guillot ◽  
Alper Erturk

Vibration-based energy harvesting is a growing field for generating low-power electricity to use in wireless electronic devices, such as the sensor networks used in structural health monitoring applications. Locally resonant metastructures, which are structures that comprise locally resonant metamaterial components, enable bandgap formation at wavelengths much longer than the lattice size, for critical applications such as low-frequency vibration attenuation in flexible structures. This work aims to bridge the domains of energy harvesting and locally resonant metamaterials to form multifunctional structures that exhibit both low-power electricity generation and vibration attenuation capabilities. A fully coupled electromechanical modeling framework is developed for two characteristic systems and their modal analysis is presented. Simulations are performed to explore the vibration and electrical power frequency response maps for varying electrical load resistance, and optimal loading conditions are presented. Case studies are presented to understand the interaction of bandgap formation and energy harvesting capabilities of this new class of multifunctional energy-harvesting locally resonant metastructures. It is shown that useful energy can be harvested from the locally resonant metastructure without significantly diminishing their dramatic vibration attenuation in the locally resonant bandgap. Thus, by integrating energy harvesters into a locally resonant metastructure, there is new potential for multifunctional self-powering or self-sensing locally resonant metastructures.


2018 ◽  
Vol 28 (07) ◽  
pp. 1850092 ◽  
Author(s):  
Bo Yan ◽  
Shengxi Zhou ◽  
Grzegorz Litak

The tristable energy harvesters (TEH) can achieve broadband energy harvesting performance from low frequency and low level excitations. Previous studies mainly focused on the tristable energy harvesting structure that is connected to a pure resistor. This paper presents an enhanced TEH with a series resistor-inductor resonant (RL) circuit connected to the piezoelectric layers. The influence of the resonant frequency of the circuit, the excitation level, and equilibrium positions on dynamic responses is analyzed using modern methods of nonlinear dynamics. The results demonstrate that the proposed TEH undergoes the periodic and chaotic motions alternatively along with the increase of the resonant frequency of the RL circuit. Furthermore, the TEH with a RL circuit dramatically enhances the energy harvesting efficiency, and simultaneously slightly decreases the vibration response. The presented TEH with a RL circuit will open a new page in the nonlinear energy harvesting technology.


2021 ◽  
Vol 7 (2) ◽  
pp. 771-774
Author(s):  
Franz Selbmann ◽  
Mario Baum ◽  
Marco Bobinger ◽  
Markus Gottwald ◽  
Maik Wiemer ◽  
...  

Abstract Triboelectric nanogenerators (TENGs) are energy converters or energy harvesters that convert mechanical motion into electrical energy on the basis of their material properties. A particular advantage of the TENG is its ability to convert small, low-frequency and random mechanical movements that are relevant for body movements and wearable applications. Within the presented study, different Parylene types were analysed as the dielectric material in TENG and found to be promising with respect to providing high output voltages and powers, respectively. Besides the verification of the usability of Parylene for TENG and its superior triboelectric properties, also significant differences were found between the Parylene types.


2021 ◽  
Author(s):  
E. van de Wetering ◽  
T. W. A. Blad ◽  
R. A. J. van Ostayen

Abstract In this work, a piezoelectric beam is stiffness compensated through adding a negative stiffness formed by attracting magnets. The mechanism’s purpose is low-frequency energy harvesting. The effect of deformation speed on the beam’s stiffness is investigated by force-displacement measurements taken at different speeds and with different load resistors connected. The effect of the load resistance on the beam’s stiffness has been found to be strongly dependent on the deformation speed. A load that results in the same stiffness as in a closed circuit at low deformation speed results in a stiffer response at a faster deformation speed. Also, when the beam is brought close to static balance with a certain load resistance connected, alteration of the load resistance has a great influence on the attained stiffness level. Furthermore, memory effects in the hysteresis found in piezoelectric actuators, related between input voltage and displacement, were also confirmed between displacement and force in sensor application.


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