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.

scholarly journals The Effect of Axial Displacement of Magnets in Piezoelectric Energy Harvester

2018 ◽  
Vol 7 (3.7) ◽  
pp. 95
Author(s):  
Li Wah Thong ◽  
Yu Jing Bong ◽  
Swee Leong Kok ◽  
Roszaidi Ramlan
Keyword(s):  
Frequency Spectrum ◽  
Power Output ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Operational Frequency ◽  
And Performance

The utilization of vibration energy harvesters as a substitute to batteries in wireless sensors has shown prominent interest in the literature. Various approaches have been adapted in the energy harvesters to competently harvest vibrational energy over a wider spectrum of frequencies with optimize power output.   A typical bistable piezoelectric energy harvester, where the influence of magnetic field is induced into a linear piezoelectric cantilever, is designed and analyzed in this paper. The exploitations of the magnetic force specifically creates nonlinear response and bistability in the energy harvester that extends the operational frequency spectrum for optimize performance.  Further analysis on the effects of axial spacing displacement between two repulsive magnets of the harvester, in terms of x-axis (horizontal) and z-axis (vertical) on its natural resonant frequency and performance based on the frequency response curve are investigated for realizing optimal power output. Experimental results show that by selecting the optimal axial spacing displacement, the vibration energy harvester can be designed to produce maximized output power in an improved broadband of frequency spectrum.  

Uncertainty Analysis of Energy Harvesting Systems

2014 ◽  
Author(s):  
Reza Madankan ◽  
M. Amin Karami ◽  
Puneet Singla
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Design Parameters ◽  
Unscented Transformation ◽  
Energy Harvesters ◽  
Harvesting Systems

This paper presents the relation between uncertainty in the excitation and parameters of vibrational energy harvesting systems and their power output. Nonlinear vibrational energy harvesters are very sensitive to the frequency of the base excitation. If the excitation frequency does not match with the resonance frequency of the energy harvester, the power output significantly deteriorates. The mismatch can be due to the inherent changes of the ambient oscillations. The fabrication errors or gradual changes of material properties also result in the mismatch. This paper quantitatively shows the probability density function for the power as a function of the probability densities of the excitation frequency, excitation amplitude, initial deflection of the energy harvester, and design parameters. Recently developed the conjugated unscented transformation methodology is used in conjunction with the principle of maximum entropy to compute the probability distribution for the base response and power. The computed nonlinear density functions are validated against Monte Carlo simulations.

Hybrid Rotary-Translational Energy Harvester for Multi-Axis Ambient Vibrations

2012 ◽  
Author(s):  
M. Amin Karami ◽  
Daniel J. Inman
Keyword(s):  
Energy Harvester ◽  
Vibrational Energy ◽  
Period Doubling ◽  
Translational Energy ◽  
Ambient Vibrations ◽  
Energy Harvesters ◽  
Specific Direction ◽  
Electromagnetic Coils ◽  
Representative Model ◽  
Energy Harvesting System

A nonlinear electromagnetic energy harvester is presented which can generate power from translational vibrations in two directions and rotational excitations. Commonly, vibrational energy harvesters are designed to generate power from only translational ambient oscillations in a specific direction. The assumption of uni-axial ambient vibrations is too idealistic. Not only the direction of the base excitations typically change in time but also the rotational excitations are as common in oscillating machinery as the translational vibrations. The proposed energy harvester is inspired by the Automatic Generating System in Seiko watches. The moving element is a magnetic pendulum. When the pendulum moves in response to the base excitations the magnetic tip passes over electromagnetic coils, positioned in a circular array in the stator. The relative motion of the tip magnet and the coil generates electricity. The paper presents an analytical representative model for the energy harvesting system. The dynamics and energy generation of the energy harvester in response to four different excitation configurations are studied. It is demonstrated that in response to large excitations the system commonly undergoes period doubling bifurcations and occasionally undergoes chaos. The study paves the way to optimal design of the hybrid rotary translational energy harvesters.

Ultra-Long Barium Titanate Nanowire Arrays for Low Frequency Energy Harvesting Applications

2014 ◽  
Author(s):  
Aneesh Koka ◽  
Henry A. Sodano
Keyword(s):  
Barium Titanate ◽  
Energy Harvesting ◽  
Resonant Frequency ◽  
Vibrational Energy ◽  
Low Frequency ◽  
Piezoelectric Response ◽  
Synthesis Process ◽  
Mechanical Vibrations ◽  
Energy Harvesters ◽  
Vertically Aligned

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.

An Axially-Suspended Vibration Energy Harvesting Beam for Broadband Performance and High Versatility

2014 ◽  
Author(s):  
R. L. Harne ◽  
K. W. Wang
Keyword(s):  
Alternative Energy ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
High Energy ◽  
Electrostatic Energy ◽  
Vibration Energy Harvesting ◽  
Energy Harvesters ◽  
Wide Range ◽  
Fine Control ◽  
Self Powered

It has recently been shown that negligible linear stiffness or very small negative stiffness may be the most beneficial stiffness nonlinearities for vibrational energy harvesters due to the broadband, amplified responses which result from such designs. These stiffness characteristics are often achieved by providing axial compression along the length of a harvester beam. Axial compressive forces induced using magnetic or electrostatic effects are often easily tuned; however, electrostatic energy harvesters are practically limited to microscale realizations and magnets are not amenable in a variety of applications, e.g. self-powered biomedical implants or when the harvesters are packaged with particular circuits. On the other hand, mechanically-induced pre-compression methods considered to date are less able to achieve fine control of the applied force which is typically governed by a pre-compression distance that has practical constraints such as resolution and tolerance. This notably limits the harvester’s ability to precisely obtain the desired near-zero or small negative linear stiffness and thus inhibits the favorable dynamical phenomena that lead to high energy conversion performance. Inspired by the wing motor structure of the common diptera (fly), this research explores an alternative energy harvester design and configuration that considerably improves control over pre-compression factors and their influence upon performance-improving dynamics. A pre-compressed harvester beam having an axial suspension on an end is investigated through theoretical and numerical studies and experimental efforts. Suspension and pre-loading adjustments are found to enable comprehensive variation over the resulting dynamics. It is shown that the incorporation of adjustable axial suspension into the design of pre-compressed energy harvester beams is therefore a versatile, all-mechanical means to enhance the performance of such devices and ensure favorable dynamics are retained across a wide range of excitation conditions.

Design of a Compliant Flexure Joint for Use in a Flow Energy Harvester

2014 ◽  
Author(s):  
Punnag Chatterjee ◽  
Matthew Bryant
Keyword(s):  
Energy Harvester ◽  
Vibrational Energy ◽  
Electrical Power ◽  
Flow Induced Vibration ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Flow Energy ◽  
Flexure Mechanism ◽  
Multiple Components ◽  
Compact Design

This paper presents an initial experimental and computational investigation of a flow-induced vibration energy harvester with a compliant flexure mechanism. This energy harvester utilizes the aeroelastic flutter phenomenon to convert the flow energy to vibrational energy which can be converted into useful electrical power using piezoelectric transducers. However, unlike previous flutter-based flow energy harvesters [1] which require assembling multiple components to create the necessary aeroelastic arrangement, the device described here utilizes a monolithic, compact design to achieve the same. In this paper, we propose a flexure design for this device and model it using analytic methods and finite element simulations. A proof of concept energy harvester incorporating this flexure design has been fabricated and experimentally investigated in wind tunnel testing.

Influence of Bias Angle on Output Performance of Nonlinear Asymmetric Energy Harvesters: Experimental Investigation

2018 ◽  
Author(s):  
Wei Wang ◽  
Junyi Cao ◽  
Ying Zhang ◽  
Chris R. Bowen
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Performance Enhancement ◽  
Vibrational Energy ◽  
Experimental System ◽  
Harmonic Excitation ◽  
Nonlinear Phenomena ◽  
Energy Harvesters ◽  
Output Performance ◽  
Piezoelectric Energy

In recent decades, the technique of piezoelectric energy harvesting has drawn a great deal of attention since it is a promising method to convert vibrational energy to electrical energy to supply lower-electrical power consumption devices. The most commonly used configuration for energy harvesting is the piezoelectric cantilever beam. Due to the inability of linear energy harvesting to capture broadband vibrations, most researchers have been focusing on broadband performance enhancement by introducing nonlinear phenomena into the harvesting systems. Previous studies have often focused on the symmetric potential harvesters excited in a fixed direction and the influence of the gravity of the oscillators was neglected. However, it is difficult to attain a completely symmetric energy harvester in practice. Furthermore, the gravity of the oscillator due to the change of installation angle will also exert a dramatic influence on the power output. Therefore, this paper experimentally investigates the influence of gravity due to bias angle on the output performance of asymmetric potential energy harvesters under harmonic excitation. An experimental system is developed to measure the output voltages of the harvesters at different bias angles. Experimental results show that the bias angle has little influence on the performance of linear and monostable energy harvesters. However, for an asymmetric potential bistable harvester with sensitive nonlinear restoring forces, the bias angle influences the power output greatly due to the effect of gravity. There exists an optimum bias angle range for the asymmetric potential bistable harvester to generate large output power in a broader frequency range. The reason for this phenomenon is that the influence of gravity due to bias angle will balance the nonlinear asymmetric potential function in a certain range, which could be applied to improve the power output of asymmetric bistable harvesters.

Synergistic Wake Interactions in Aeroelastic Flutter Vibration Energy Harvester Arrays

2011 ◽  
Author(s):  
Matthew Bryant ◽  
Ranjeev L. Mahtani ◽  
Ephrahim Garcia
Keyword(s):  
Power Output ◽  
Energy Harvester ◽  
Oscillation Amplitude ◽  
Interaction Effects ◽  
Separation Distance ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Aeroelastic Flutter ◽  
Wake Interaction ◽  
Wake Interactions

This research experimentally investigates the operation of several aeroelastic flutter energy harvesters in an array. In order for such a wind energy harvesting array to operate effectively, it is important to understand the interaction between neighboring power harvesters including downstream wake effects, and how these interactions can be leveraged to maximize the output of the system. The fluttering motion of the energy harvester imparts an unsteady wake into the flow downstream of the device. Wind tunnel experiments with a pair of flutter energy harvesters show that this wake structure has significant effects on the oscillation amplitude, frequency, and power output of the trailing device. These wake interaction effects are shown to vary with the stream-wise and cross-stream separation distance between the two devices. At some separations, an advantageous frequency lock-in between the two devices occurs. When this occurs, the wake of the leading device adds constructively with the trailing device, causing larger oscillation amplitudes and higher power output in the trailing device. Experiments to characterize this variation in power output due to these wake interaction effects and to determine the optimal spacing of the energy harvesters are presented and discussed.

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