Modeling and Experimental Validations of a Piezoelectric Energy Harvester Under Combined Galloping and Base Excitations

2014 ◽  
Author(s):  
Amin Bibo ◽  
Abdessattar Abdelkefi ◽  
Mohammed F. Daqaq
Keyword(s):  
Bluff Body ◽  
Energy Harvester ◽  
Constitutive Relations ◽  
Excitation Frequency ◽  
Primary Resonance ◽  
Beam Theory ◽  
Excitation Amplitude ◽  
The Body ◽  
Base Excitation ◽  
Piezoelectric Energy

This paper develops an experimentally validated model of a piezoelectric energy harvester under combined aeroelastic-galloping and base excitations. To that end, an energy harvester consisting of a thin piezoelectric cantilever beam subjected to vibratory base excitation is considered. To permit galloping excitation, a bluff body is rigidly attached at the free end such that a net aerodynamic lift is generated as the incoming airflow separates on both sides of the body giving rise to limit cycle oscillations when the flow velocity exceeds a critical value. A nonlinear electromechanical distributed-parameter model of the harvester under the combined excitation is derived using the energy approach and by adopting the nonlinear Euler-Bernoulli beam theory, linear constitutive relations for the piezoelectric transduction, and the quasi-steady assumption for the aerodynamic loading. The partial differential equations of the system are discretized and a reduced-order-model is obtained. The mathematical model is validated by conducting a series of experiments with different loading conditions represented by wind speed, base excitation amplitude, and excitation frequency around the primary resonance.

Modeling and Characterization of a Piezoelectric Energy Harvester Under Combined Aerodynamic and Base Excitations

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Amin Bibo ◽  
Abdessattar Abdelkefi ◽  
Mohammed F. Daqaq
Keyword(s):  
Bluff Body ◽  
Energy Harvester ◽  
Constitutive Relations ◽  
Equations Of Motion ◽  
Primary Resonance ◽  
Beam Theory ◽  
Combined Loading ◽  
Response Behavior ◽  
Piezoelectric Energy ◽  
Piezoelectric Cantilever

This paper develops and validates an aero-electromechanical model which captures the nonlinear response behavior of a piezoelectric cantilever-type energy harvester under combined galloping and base excitations. The harvester consists of a thin piezoelectric cantilever beam clamped at one end and rigidly attached to a bluff body at the other end. In addition to the vibratory base excitations, the beam is also subjected to aerodynamic forces resulting from the separation of the incoming airflow on both sides of the bluff body which gives rise to limit-cycle oscillations when the airflow velocity exceeds a critical value. A nonlinear electromechanical distributed-parameter model of the harvester under the combined excitations is derived using the energy approach and by adopting the nonlinear Euler–Bernoulli beam theory, linear constitutive relations for the piezoelectric transduction, and the quasi-steady assumption for the aerodynamic loading. The resulting partial differential equations of motion are discretized and a reduced-order model is obtained. The mathematical model is validated by conducting a series of experiments at different wind speeds and base excitation amplitudes for excitation frequencies around the primary resonance of the harvester. Results from the model and experiment are presented to characterize the response behavior under the combined loading.

scholarly journals On the Efficiency of a Piezoelectric Energy Harvester under Combined Aeroelastic and Base Excitation

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 962
Author(s):  
Antiopi-Malvina Stamatellou ◽  
Anestis I. Kalfas
Keyword(s):  
Conversion Efficiency ◽  
Power Output ◽  
Polyvinylidene Fluoride ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Elastic Strain Energy ◽  
Rate Of Change ◽  
Mode Shapes ◽  
Base Excitation ◽  
Piezoelectric Energy

A flutter-type, nonlinear piezoelectric energy harvester was tested in various combinations of aerodynamic and harmonic base excitation to study its power output and efficiency. The commercial polyvinylidene fluoride film transducer LDT1-028K was used in 33 excitation mode. The aerodynamic excitation was created by a centrifugal fan and the base excitation by a cone speaker. The excitations were produced by varying independently the mean airflow velocity and the frequency of base vibration. A capacitive load was used to store the harvested energy. A line laser was employed along with long exposure photography and high-speed video, for the visualization of the piezo film’s mode shapes and the measurement of maximum tip deflection. The harvested power was mapped along with the maximum tip deflection of the piezo-film, and a process of optimally combining the two excitation sources for maximum power harvesting is demonstrated. The energy conversion efficiency is defined by means of electrical power output divided by the elastic strain energy rate of change during oscillations. The efficiency was mapped and correlated with resonance conditions and results from other studies. It was observed that the conversion efficiency is related to the phase difference between excitation and response and tends to decrease as the excitation frequency rises.

Broadband and Low Frequency Vibration-Based Energy Harvesting Improvement Through Magnetically Induced Frequency Up-Conversion

2010 ◽  
Author(s):  
Adam M. Wickenheiser
Keyword(s):  
Energy Harvester ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Beam Theory ◽  
Magnetic Interaction ◽  
Large Mass ◽  
Stochastic Simulations ◽  
Base Excitation ◽  
Low Frequency Vibration ◽  
Compact Design

In order to extract as much energy as possible from ambient vibrations, many vibration-based energy harvesters (VEHs) are designed to resonate at a specific base excitation frequency. Unfortunately, many vibration energy sources are low frequency (0.5 Hz–100 Hz), intermittent, and broadband. Thus, resonant VEHs would not be excited continuously and would require a large mass or size to tune to such a low frequency. This work presents the modeling, analysis, and experimental application of a nonlinear, magnetically excited energy harvester that exhibits efficient broadband, frequency-independent performance. This design utilizes a passive auxiliary structure that remains stationary relative to the base motion of the VEH. This device is especially effective for driving frequencies well below its fundamental frequency, thus enabling a more compact design compared to traditional resonant topologies. A mechanical model based on Euler-Bernoulli beam theory is coupled to a linear circuit and a model of the nonlinear, magnetic interaction to produce a distributed parameter magneto-electromechanical system. The results of both harmonic and broadband, stochastic simulations demonstrate multiple-order-of-magnitude power harvesting performance improvement at low driving frequencies and an insensitivity to time-varying base excitation frequency content. Furthermore, the proposed system is shown to enable more practical designs than a resonant energy harvester for the specific example of harvesting energy from walking motion.

Electromechanical modelling of piezoelectric vibration energy harvester with a novel dynamic magnifier

2020 ◽  
Vol 87 (9) ◽  
pp. 575-585
Author(s):  
Suresh Kote ◽  
Shankar Krishnapillai ◽  
Sujatha Chandramohan
Keyword(s):  
Output Power ◽  
Output Voltage ◽  
Degrees Of Freedom ◽  
Energy Harvester ◽  
Excitation Amplitude ◽  
Relative Displacement ◽  
Base Excitation ◽  
Vibration Energy Harvester ◽  
Piezoelectric Energy ◽  
Energy Harvesting Devices

AbstractIn piezoelectric energy harvesting devices, the relative displacement between the two ends of the harvester beam decides the output power from the piezoelectric patch. A novel four bar mechanism with a helical spring is used as a dynamic magnifier to improve the relative displacement and thereby the output power from the harvester. This dynamic magnifier is placed between the base excitation location and the composite harvester beam to form two degrees of freedom (2DOF) piezoelectric energy harvester. Electromechanical coupled analytical equations for the voltage and output power are derived using a lumped electromechanical model. The model is developed assuming linear transverse vibrations of the harvester. A dynamic magnifier is fabricated for the required frequency range and the suitable dimensions of the harvester beam are estimated using commercially available software. Experiments are conducted for base excitation amplitude of 0.05 mm and the performance of the proposed 2DOF harvester is studied for the output voltage and power. The proposed 2DOF harvester has shown 110 % improvement in output power in first mode and 270 % improvement in second mode compared to the conventional single degree of freedom (SDOF) cantilevered harvester for given identical input conditions. The measured frequencies and output power are validated with analytical solutions and are found to be in good agreement. Further, the effect of mass ratio, stiffness ratio and base excitation amplitude on the output voltage and power is investigated using analytical expressions.

scholarly journals Analysis of a Cantilevered Piezoelectric Energy Harvester in Different Orientations for Rotational Motion

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1206 ◽  
Author(s):  
Wei-Jiun Su ◽  
Jia-Han Lin ◽  
Wei-Chang Li
Keyword(s):  
Theoretical Model ◽  
Resonant Frequency ◽  
Rotational Motion ◽  
Axial Load ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Experimental Studies ◽  
Piezoelectric Energy ◽  
Piezoelectric Cantilever ◽  
Tip Mass

This paper investigates a piezoelectric energy harvester that consists of a piezoelectric cantilever and a tip mass for horizontal rotational motion. Rotational motion results in centrifugal force, which causes the axial load on the beam and alters the resonant frequency of the system. The piezoelectric energy harvester is installed on a rotational hub in three orientations—inward, outward, and tilted configurations—to examine their influence on the performance of the harvester. The theoretical model of the piezoelectric energy harvester is developed to explain the dynamics of the system and experiments are conducted to validate the model. Theoretical and experimental studies are presented with various tilt angles and distances between the harvester and the rotating center. The results show that the installation distance and the tilt angle can be used to adjust the resonant frequency of the system to match the excitation frequency.

Effects of Acoustic Excitation on a Swirling Diffusion Flame

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Michael E. Loretero ◽  
Rong F. Huang
Keyword(s):  
Flow Field ◽  
Bluff Body ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Mie Scattering ◽  
Flame Length ◽  
Laser Doppler Velocimeter ◽  
Scattering Method ◽  
Acoustic Excitation ◽  
Characteristic Modes

A swirling double concentric jet is commonly used for nonpremixed gas burner application for safety reasons and to improve the combustion performance. Fuel is generally spurted at the central jet while the annular coflowing air is swirled. They are normally separated by a blockage disk where the bluff-body effects further enhance the recirculation of hot gas at the reaction zone. This paper aims to experimentally investigate the behavior of flame and flow in a double concentric jet combustor when the fuel supply is acoustically driven. Laser-light sheet assisted Mie scattering method has been used to visualize the flow, while the flame lengths were measured by a conventional photography technique. The fluctuating velocity at the jet exit was measured by a two-component laser Doppler velocimeter. Flammability and stability at first fuel tube resonant frequency are reported and discussed. The evolution of flame profile with excitation level is presented and discussed, together with the reduction in flame length. The flame in the unforced reacting axisymmetric wake is classified into three characteristic modes, which are weak swirling flame, lifted flame, and transitional reattached flame. These terms reflect their primary features of flame appearances, and when the acoustic excitation is applied, the flame behaviors change with the excitation frequency and amplitude. Four additional characteristic modes are identified; e.g., at low excitation amplitudes, wrinkling flame with a blue annular film is observed because the excitation induces vortices in the central fuel jet and hence gives rise to the wrinkling of flame. The central jet vortices become larger with the increase in excitation amplitude and thus lead to a wider and shorter flame. If the excitation amplitude is increased above a certain value, the central jet vortices change the rotation direction and pacing with the annular jet vortices. These changes in the flow field induce large turbulent intensity and mixing and therefore make the flame looks blue and short. Further increase in the excitation amplitude would lift the flame because the flow field would be dramatically modified.

Experimental and Theoretical Study of a Dual-Beam Piezoelectric Energy Harvester With Misaligned Magnets

2018 ◽  
Author(s):  
Wei-Jiun Su ◽  
Hsuan-Chen Lu
Keyword(s):  
Energy Harvester ◽  
Theoretical Study ◽  
Beam Theory ◽  
Main Beam ◽  
Bernoulli Beam ◽  
Potential Wells ◽  
Piezoelectric Energy ◽  
Dual Beam ◽  
Frequency Sweeps ◽  
Euler Bernoulli Beam

In this study, a dual-beam piezoelectric energy harvester is proposed. This harvester consists of a main beam and an auxiliary beam with a pair of magnets attached to couple their motions. The potential energy of the system is modeled to understand the influence of the potential wells on the dynamics of the harvester. It is noted that the alignment of the magnets significantly influences the potential wells. A theoretical model of the harvester is developed based on the Euler-Bernoulli beam theory. Frequency sweeps are conducted experimentally and numerically to study the dynamics of the harvester. It is shown that the dual-beam harvester can exhibit hardening effect with different configurations of magnet alignments in frequency sweeps. The performance of the harvester can be improved with proper placement of the magnets.

Complex Impact Response of a Beam and Rigid Body Structure to Harmonic Base Excitation

2005 ◽  
Author(s):  
Elizabeth Ervin ◽  
Jonathan Wickert
Keyword(s):  
Rigid Body ◽  
Contact Stiffness ◽  
Excitation Frequency ◽  
Period Doubling ◽  
Forced Response ◽  
The Body ◽  
Body Structure ◽  
Base Excitation ◽  
Response Dynamics ◽  
Contact State

This paper investigates the forced response dynamics of a clamped-clamped beam to which a rigid body is attached, and in the presence of periodic or non-periodic impacts between the body and a comparatively compliant base structure. The assembly is subjected to base excitation at specified frequency and acceleration, and the potentially complex responses that occur are examined analytically. The two sets of natural frequencies and vibration modes of the beam-rigid body structure (in its in- contact state, and in its not-in-contact state), are used to treat the forced response problem through a series of algebraic mappings among those states. A modal analysis based on extended operators for the (continuous) beam and (discrete) rigid body establishes a piecewise linear state-to-state mapping for transition between the in-contact and not-in-contact conditions. The contact force, impulse, and displacement each exhibit complex response characteristics as a function of the excitation frequency. Periodic responses occurring at the excitation frequency, period-doubling bifurcations, grazing impacts, sub-harmonic regions, fractional harmonic resonances, and apparently chaotic responses each occur at various combinations of damping, excitation frequency, and contact stiffness. Parameter studies are discussed for structural asymmetry and eccentricity of contact point’s location.

scholarly journals Performance Analysis of an Electromagnetically Coupled Piezoelectric Energy Scavenger

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 845 ◽  
Author(s):  
Abdolreza Pasharavesh ◽  
Reza Moheimani ◽  
Hamid Dalir
Keyword(s):  
Energy Harvesting ◽  
Multiple Scales ◽  
Nonlinear Partial Differential Equations ◽  
Low Frequency ◽  
Primary Resonance ◽  
Excitation Amplitude ◽  
Load Resistance ◽  
Response Curves ◽  
Piezoelectric Energy ◽  
Resonance Frequencies

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.

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