Study of vibration modes and strain distribution of a flow energy harvester in the wake region of different bluff bodies

2021 ◽  
pp. 095440622199673
Author(s):  
Ankit Agarwal ◽  
Ashish Purohit
Keyword(s):  
Energy Harvesting ◽  
Cross Sections ◽  
Strain Distribution ◽  
Bluff Body ◽  
Mode Shapes ◽  
Bluff Bodies ◽  
Vibration Modes ◽  
Peak Strain ◽  
Piezoelectric Energy ◽  
Cumulative Strain

This paper aims to analyze mode shapes and corresponding strain distribution in a two-dimensional plane structure exhibiting flow-induced vibration in the wake field of four different upstream bluff bodies such as cylinder, square, triangle, and D-shape. This research is important from the point of view of flow-induced piezoelectric energy harvesting; wherein, induced strain in the structure is directly related to the amount of energy generated. Mainly, all investigations are carried out at low Reynolds number ( Re = 200); however, to widen the scope of the work, other Reynolds numbers are also considered ( Re = 300, 500, and 750 ). The results obtained indicated that the plane structure vibrates in different mode shapes under different wake fields. The square section dominantly gives rise to the fundamental mode vibration, whereas, cylinder, D-shape, and triangular bluff body induce vibration in a mix of fundamental and higher bending modes. Analysis of the corresponding flow regime shows that the position of reattachment point of the downstream shear layer plays an important role in the realization of different vibration modes. The strain distribution under different cases revealed that the wake of a cylindrical bluff body produces highest peak strain, and D-shape bluff body results in highest cumulative strain. From the aspect of energy harvesting, a quantitative comparison of strain-induced and per second charge generation have indicated that for an equivalent flow condition, the D-shape will produce higher energy per unit time than the cases of a square, cylinder, and triangular cross-sections.

Multiple Patch-Based Piezoelectric Energy Harvesting From Multiple Vibration Modes of Thin Plates

2013 ◽  
Author(s):  
Ugur Aridogan ◽  
Ipek Basdogan ◽  
Alper Erturk
Keyword(s):  
Energy Harvesting ◽  
Thin Plates ◽  
Aluminum Plate ◽  
Piezoelectric Energy Harvesting ◽  
Vibration Modes ◽  
Piezoelectric Energy ◽  
Wide Range ◽  
Resistive Loads ◽  
Experimental Validations ◽  
Piezoelectric Cantilevers

Vibration-based energy harvesting using cantilevered piezoelectric beam has been extensively studied over the last decade. In this study, as an alternative to resonant piezoelectric cantilevers, we studied multiple patch-based piezoelectric energy harvesting from multiple vibration modes of thin plates. Analytical electroelastic model of the multiple patch-based piezoelectric harvesters attached on a thin plate is provided based on distributed-parameter modeling approach for series and parallel configurations of the patches. An experimental setup is built with series-configuration of double patch-based harvesters attached on the surfaces of all-four-edges clamped (CCCC) rectangular aluminum plate. Analytical simulations and experimental validations of power generation of the harvesters are performed in a case study. The experimental and analytical frequency response functions (FRF) relating voltage output and vibration response to force input are obtained. The analytical model is validated by comparing analytical and experimental FRFs for a wide range of resistive electrical boundary conditions. The harvested power output across the various resistive loads is explored with a focus on the first four modes of the aluminum plate. Experimental and analytical results are shown to be in agreement for multiple patch-based piezoelectric energy harvesting from multiple vibration modes of thin plates.

Synchronization of Cantilevers Arranged in Line of a Piezoelectric Energy Harvester

2015 ◽  
Author(s):  
Max Spornraft ◽  
Norbert Schwesinger ◽  
Shlomo Berger
Keyword(s):  
Energy Harvesting ◽  
Bluff Body ◽  
Energy Harvester ◽  
Phase Synchronization ◽  
Vibrational Excitation ◽  
Line Energy ◽  
Mechanical Coupling ◽  
Piezoelectric Energy ◽  
Piezoelectric Cantilever ◽  
The Right

Synchronization opens further ways to improve cantilever-based energy harvesting arrays in view of power output, easier rectification and scaling. Objective of this study is to investigate the synchronization behavior of a cantilever-array based energy harvesting systems. Thereby, synchronization is achieved by mechanical coupling through a so-called “overhang”. Nakajima et al. [1] and Wang et al. [2] already verified this principle for the synchronization of two and three cantilevers, but at constant vibrational excitation. Regarding energy harvesting, no application of this method is presently available. In this paper, we investigate the synchronization behavior of a piezoelectric cantilever-line energy harvester in airflow. The design of the energy harvester bases upon a piezoelectric cantilever-line and a common bluff body, arranged upstream. To investigate synchronization of the cantilevers, three commonly available piezoelectric bimorphs were employed to study synchronization. Mounted on a common bluff body, the effect of overhang material and position was studied. Therefore, different constellations were examined by impulse excitation as well as vortex-induced vibration in a wind channel. In several measurements, we found arrangements and parameters allowing for an in-phase synchronization of neighborly cantilevers of the line. The knowledge gained allows for a direct electrical connection of piezoelectric cantilevers with just one single rectifier unit. Cantilevers coupled with overhangs arranged in the right order oscillate with the same frequency and phase, i.e. without any charge cancellations. This knowledge opens ways to develop basic design rules for the synchronization of cantilevers.

A Low-order Model for the Design of Piezoelectric Energy Harvesting Devices

2008 ◽  
Vol 20 (5) ◽  
pp. 495-504 ◽  
Author(s):  
Jeffrey L. Kauffman ◽  
George A. Lesieutre
Keyword(s):  
Energy Harvesting ◽  
Design Tool ◽  
Mode Shapes ◽  
Piezoelectric Energy Harvesting ◽  
Coupling Coefficients ◽  
Order Model ◽  
Power Sources ◽  
Piezoelectric Energy ◽  
Energy Harvesting Devices ◽  
Low Order

Piezoelectric energy harvesting devices are an attractive approach to providing remote wireless power sources. They operate by converting available vibration energy and storing it as electrical energy. Currently, most devices rely on mechanical excitation near their resonance frequency, so a low-order model which computes a few indicators of device performance is a critical design tool. Such a model, based on the assumed modes method, develops equations of motion to provide rapid computations of key device parameters, such as the natural frequencies, mode shapes, and electro-mechanical coupling coefficients. The model is validated with a comparison of its predictions and experimental data.

scholarly journals The State-of-the-Art Brief Review on Piezoelectric Energy Harvesting from Flow-Induced Vibration

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Hongjun Zhu ◽  
Tao Tang ◽  
Huohai Yang ◽  
Junlei Wang ◽  
Jinze Song ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Bluff Body ◽  
Mechanical Energy ◽  
Wake Flow ◽  
Structural Vibration ◽  
Small Scale ◽  
Flow Induced Vibration ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Self Powered

Flow-induced vibration (FIV) is concerned in a broad range of engineering applications due to its resultant fatigue damage to structures. Nevertheless, such fluid-structure coupling process continuously extracts the kinetic energy from ambient fluid flow, presenting the conversion potential from the mechanical energy to electricity. As the air and water flows are widely encountered in nature, piezoelectric energy harvesters show the advantages in small-scale utilization and self-powered instruments. This paper briefly reviewed the way of energy collection by piezoelectric energy harvesters and the various measures proposed in the literature, which enhance the structural vibration response and hence improve the energy harvesting efficiency. Methods such as irregularity and alteration of cross-section of bluff body, utilization of wake flow and interference, modification and rearrangement of cantilever beams, and introduction of magnetic force are discussed. Finally, some open questions and suggestions are proposed for the future investigation of such renewable energy harvesting mode.

Piezoelectric Energy Harvesting Through Fluid Excitation

2012 ◽  
Author(s):  
Andrew Truitt ◽  
S. Nima Mahmoodi
Keyword(s):  
Energy Harvesting ◽  
Degrees Of Freedom ◽  
Flow Speed ◽  
Bluff Bodies ◽  
Mems Devices ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Cantilevered Beam ◽  
Self Powered ◽  
New Research

Piezoelectric energy harvesters have recently captured a lot of attention in research and technology. They employ the piezoelectric effect, which is the separation of charge within a material as a result of an applied strain, to turn what would otherwise be wasted energy into usable energy. This energy can then be used to support remote sensing systems, batteries, and other types of wireless MEMS devices. Such self powered systems are particularly attractive where hardwiring may not be feasible or numerous battery sources unreasonable. The source of excitation for these systems can include direct actuation, natural or mechanical vibrations, or fluid energy (aerodynamic or hydrodynamic). Fluid based energy harvesting is increasingly pursued due to the ubiquitous nature of the excitation source as well as the strong correlation with other types of excitation. Vortex-induced vibrations as well as vibrations induced by bluff bodies have been investigated to determine potential gains. The shape and size of these bluff bodies has been modeled in order to achieve the maxim power potential of the system. Other studies have focused on aeroelastic fluttering which relies on the natural frequency of two structural modes being achieved through aerodynamic forces. Rather than a single degree of freedom, as seen in the VIV approach, aeroelastic flutter requires two degrees of freedom to induce its vibrational state. This has been modeled through a wing section attached to a cantilevered beam via a revolute joint. To accurately model the behavior of these systems several types of dampening must be considered. Fluid flow excitation introduces the component of dampening via fluid dynamics in addition to structural dampening and electrical dampening from the piezoelectrics themselves. Air flow speed modifies the aerodynamic dampening and it has been shown that at the flutterer boundary the aerodynamic dampening dissipates while the oscillations remain. However, such a system state exhibits a decaying power output due to the shunt dampening effect of the power generation itself. Research in energy harvesting is quickly progressing but much has yet to be discovered. The focus of this paper will be fluid as a source of excitation and the development that has followed thus far. Configurations and applications of previous works will be examined followed by suggestions of new research works to move forward in the field.

Rotary Multimodal Energy Harvesting Device

2013 ◽  
Author(s):  
Miles Larkin ◽  
Yonas Tadesse
Keyword(s):  
Energy Harvesting ◽  
Numerical Simulations ◽  
Load Resistance ◽  
Human Motion ◽  
Mode Shapes ◽  
Optimum Operating ◽  
Linear Motion ◽  
Operating Modes ◽  
Piezoelectric Energy ◽  
Impact Forces

In this paper, a new multimodal energy harvesting device consisting of two transduction mechanisms and having unique properties at various operating modes is presented. The hybrid system includes electromagnetic and piezoelectric energy harvesting technologies, and uses linear motion and impact forces from human motion for energy harvesting. The device is based on an unbalanced electromagnetic rotor made of three beams of piezoelectric material that have magnets attached to the ends. The device is to be worn on the legs or arms of a person. Linear motion, from the arms or legs swinging, causes the rotor to spin and the magnets to pass over the coils. Impact forces, from stepping, induce stress on the piezoelectrics which generates voltage across the electrode. The results of several numerical simulations are presented. For the piezoelectric beams, numerical simulations were done to find the deflection, stress, optimum operating frequency, and mode shapes taking into account environmental conditions. For the electromagnetic generation, numerical simulations were done to find the optimal load resistance and power generation for several different orientations. Other design related issues will also be investigated to fully realize the device in real world applications.

scholarly journals Ceramic-Based Piezoelectric Material for Energy Harvesting Using Hybrid Excitation

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5816
Author(s):  
Bartłomiej Ambrożkiewicz ◽  
Zbigniew Czyż ◽  
Paweł Karpiński ◽  
Paweł Stączek ◽  
Grzegorz Litak ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Energy Harvesting ◽  
Piezoelectric Material ◽  
Lead Zirconate Titanate ◽  
Bluff Body ◽  
Fiber Composite ◽  
Air Flow ◽  
Linear Acceleration ◽  
Test Rig ◽  
Piezoelectric Energy

This paper analyzes the energy efficiency of a Micro Fiber Composite (MFC) piezoelectric system. It is based on a smart Lead Zirconate Titanate material that consists of a monolithic PZT (piezoelectric ceramic) wafer, which is a ceramic-based piezoelectric material. An experimental test rig consisting of a wind tunnel and a developed measurement system was used to conduct the experiment. The developed test rig allowed changing the air velocity around the tested bluff body and the frequency of forced vibrations as well as recording the output voltage signal and linear acceleration of the tested object. The mechanical vibrations and the air flow were used to find the optimal performance of the piezoelectric energy harvesting system. The performance of the proposed piezoelectric wind energy harvester was tested for the same design, but of different masses. The geometry of the hybrid bluff body is a combination of cuboid and cylindrical shapes. The results of testing five bluff bodies for a range of wind tunnel air flow velocities from 4 to 15 m/s with additional vibration excitation frequencies from 0 to 10 Hz are presented. The conducted tests revealed the areas of the highest voltage output under specific excitation conditions that enable supplying low-power sensors with harvested energy.

Piezoelectric energy harvesting using L-shaped structures

2017 ◽  
Vol 29 (6) ◽  
pp. 1206-1215 ◽  
Author(s):  
Donghuan Liu ◽  
Mohammed Al-Haik ◽  
Mohamed Zakaria ◽  
Muhammad R Hajj
Keyword(s):  
Energy Harvesting ◽  
Power Density ◽  
Cantilever Beam ◽  
Strain Distribution ◽  
Uniform Strain ◽  
Main Beam ◽  
Piezoelectric Energy Harvesting ◽  
Frequency Range ◽  
Piezoelectric Energy

Energy harvesting from an L-shaped structure, formed by two beams and corner and end masses, is investigated with the objective of expanding the bandwidth of the frequency range over which energy can be harvested. The structure is excited in a direction that yields the most uniform strain distribution along its main beam. The length of the auxiliary beam is varied to determine its effect on the level and breadth of the frequency range over which energy can be harvested. Results from experiments having different geometries are presented and discussed. It is determined that the frequency range over which energy can be harvested from such structures is much larger than levels harvested when using a cantilever beam. The experiments also show that L-shaped structures harvest more power when the length of the auxiliary beam is increased. On the contrary, the power density of the L-shaped structure is much smaller than that of the cantilever beam. The ability to control the bandwidth of frequency over which energy is harvested through proper adjustment of beam lengths is demonstrated.

Exploiting a Tail Fin to Improve the Performance of Galloping Flow Energy Harvesters

2016 ◽  
Author(s):  
James H. Noel ◽  
Mohammed F. Daqaq
Keyword(s):  
Transient Response ◽  
Bluff Body ◽  
Critical Issue ◽  
Flow Speed ◽  
Performance Criterion ◽  
Bluff Bodies ◽  
Energy Harvesters ◽  
Flow Energy ◽  
Piezoelectric Energy ◽  
Major Player

Flow energy harvesters (FEHs) have recently emerged as a major player in the field of micro-power generation. Such devices are designed to harness energy from a dynamic flow field, typically wind, in order to power remote, sub-milliwatt consumption sensors that are hard to access or maintain. Previous research efforts have focused on harnessing flow energy under nearly steady conditions where measurable variations in the flow speed occur at a much longer time scale than the time constant of the harvester itself. Under such conditions, the nature of the harvester’s transient response is irrelevant and does not constitute a critical performance criterion. However, since gusts of wind also contain a significant amount of energy, designing FEHs to have a fast transient response is essential to capture the maximum possible energy from the flow. To address this critical issue, we propose a galloping piezoelectric energy harvester consisting of piezoelectric cantilever beam with a modified bluff body mounted at its tip. Square, trapezoid, and triangle bluff bodies were tested, each augmented with a tail fin to enhance the transient response of the harvester. It is shown experimentally that the settling time of the response and the steady state output power can be improved substantially when the fin is added.

Sign in / Sign up

Export Citation Format

Share Document