Rotational nonlinear double-beam energy harvesting

2021 ◽  
Author(s):  
Zeqi Lu ◽  
Fei-Yang Zhang ◽  
Hailing Fu ◽  
Hu Ding ◽  
Li-Qun Chen
Keyword(s):  
Theoretical Model ◽  
Energy Harvesting ◽  
Rotational Motion ◽  
Beam Energy ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Lagrange Equations ◽  
Wide Range ◽  
Double Beam ◽  
Lower Beam

Abstract This paper presents an investigation of the performance of a coupled rotational double-beam energy harvester (DBEH) with magnetic nonlinearity. Two spring-connected cantilever beams are fixed on a rotating disc. Repelling magnets are attached to the frame and to the lower beam tip, and an equal-mass block is attached to the tip of the upper beam. To describe the dynamic response, a theoretical model related to the rotational motion of the coupled cantilever beam is derived from the Lagrange equations. In addition, the harmonic balance method, together with the arc-length continuation method, is applied to obtain the frequency response functions (FRFs). Parametric studies are then conducted to analyze the effect of varying the parameters on the energy harvesting performance, and numerical analysis is performed to validate the analytical solutions. Finally, the theoretical model is verified by forward- and reverse-frequency-sweeping experiments. The DBEH in rotational motion can perform effective energy harvesting over a wide range of rotational frequencies (10 to 35 rad/s). The upper beam is found to exhibit better energy harvesting efficiency than the lower beam around the resonant frequency. This study effectively broadens the energy harvesting bandwidth and provides a theoretical model for the design of nonlinear magnet-coupled double-beam structure in rotational energy harvesting.

A study on nonlinear, parametric aeroelastic energy harvesters under oscillatory airflow

2020 ◽  
pp. 107754632097447
Author(s):  
Mohammad Mehdi Meshki ◽  
Ali Salehzadeh Nobari ◽  
Mohammad Homayoune Sadr
Keyword(s):  
Parametric Excitation ◽  
Indirect Effects ◽  
Harmonic Balance ◽  
Energy Harvester ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Direct And Indirect Effects ◽  
Flow Oscillation ◽  
Energy Harvesters ◽  
Wide Range

In this study, based on parametric excitation originating from airflow oscillation, a novel nonlinear aeroelastic energy harvester is proposed. In this respect, first, the governing equation of the system is derived and studied thoroughly to understand the direct and indirect effects of airflow oscillation on the local and global responses of the system. Then, by using a pseudo-arclength continuation method based on the harmonic balance method, the stable and unstable periodic and quasi-periodic responses of the system are tracked and analyzed. It is demonstrated that the proposed self-parametric (combination parametric and self-excitation) energy harvester can extract more power than the respective nonparametric system for a wide range of amplitudes and frequencies. The gained knowledge of parametric, aeroelastic systems is applicable for both aero-harvesters and other aeroelastic systems undergoing flow oscillation.

scholarly journals Theoretical and Experimental Investigations of a Pseudo-Magnetic Levitation System for Energy Harvesting

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1623
Author(s):  
Krzysztof Kecik ◽  
Andrzej Mitura
Keyword(s):  
Energy Harvesting ◽  
Electromechanical Coupling ◽  
Magnetic Levitation ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Path Following ◽  
Experimental Investigations ◽  
System Response ◽  
Electrical Systems ◽  
Magnetic Levitation System

The paper presents an analytical, numerical and experimental analysis of the special designed system for energy harvesting. The harvester system consists of two identical magnets rigidly mounted to the tube’s end. Between them, a third magnet is free to magnetically levitate (pseudo-levitate) due to the proper magnet polarity. The behaviour of the harvester is significantly complicated by a electromechanical coupling. It causes resonance curves to have a distorted shape and a new solution from which the recovered energy is higher is observed. The Harmonic Balance Method (HBM) is used to approximately describe the response and stability of the mechanical and electrical systems. The analytical results are verified by a numerical path following (continuation) method and experiment test with use of a shaker. The influence of harvester parameters on the system response and energy recovery near a main resonance is studied in detail.

Design and modeling of a flexible longitudinal zigzag structure for enhanced vibration energy harvesting

2016 ◽  
Vol 28 (3) ◽  
pp. 367-380 ◽  
Author(s):  
Shengxi Zhou ◽  
Weijia Chen ◽  
Mohammad H Malakooti ◽  
Junyi Cao ◽  
Daniel J Inman
Keyword(s):  
Theoretical Model ◽  
Energy Harvesting ◽  
Free Vibration Analysis ◽  
Free Vibrations ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Element Analysis ◽  
Low Frequencies ◽  
Wide Range ◽  
Zigzag Structure

The use of piezoelectric materials for vibration energy harvesting at low frequencies is challenging and requires innovative structural design. Here, a flexible longitudinal zigzag structure is developed to enhance energy harvesting at low-frequency ambient vibrations. The proposed structure is composed of orthogonal beams which enable vibration energy harvesting in two directions. A theoretical model based on Euler–Bernoulli beam theory is formulated to study the dynamic response of the structure under free vibrations. The free vibration analysis demonstrates that low operating frequencies can be obtained by increasing the number of, and/or the length of, beams in the proposed structure. To validate the accuracy of the developed theoretical model, finite element analysis is performed using ANSYS. On verification of the model’s accuracy, the piezoelectric effect of the active beams is considered in the model to evaluate the energy harvesting performance of the proposed flexible longitudinal zigzag structure. Numerical results demonstrate that the output voltage and the working frequency of these energy harvesting structures can be tailored through simply altering the number of beams. Overall, the results indicate that the proposed structure is capable of efficient energy conversion at low frequencies, which makes them suitable for a wide range of working conditions.

Effects of nonlinear interactions of flexural modes on the performance of a beam autoparametric vibration absorber

2019 ◽  
Vol 26 (7-8) ◽  
pp. 459-474
Author(s):  
Saeed Mahmoudkhani ◽  
Hodjat Soleymani Meymand
Keyword(s):  
Frequency Response ◽  
Internal Resonance ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Vibration Absorber ◽  
Primary System ◽  
Lumped Mass ◽  
Response Curves ◽  
Internal Resonances ◽  
The One

The performance of the cantilever beam autoparametric vibration absorber with a lumped mass attached at an arbitrary point on the beam span is investigated. The absorber would have a distinct feature that in addition to the two-to-one internal resonance, the one-to-three and one-to-five internal resonances would also occur between flexural modes of the beam by tuning the mass and position of the lumped mass. Special attention is paid on studying the effect of these resonances on increasing the effectiveness and extending the range of excitation amplitudes at which the autoparametric vibration absorber remains effective. The problem is formulated based on the third-order nonlinear Euler–Bernoulli beam theory, where the assumed-mode method is used for deriving the discretized equations of motion. The numerical continuation method is then applied to obtain the frequency response curves and detect the bifurcation points. The harmonic balance method is also employed for detecting the type of internal resonances between flexural modes by inspecting the frequency response curves corresponding to different harmonics of the response. Parametric studies on the performance of the absorber are conducted by varying the position and mass of the lumped mass, while the frequency ratio of the primary system to the first mode of the beam is kept equal to two. Results indicated that the one-to-five internal resonance is especially responsible for the considerable enhancement of the performance.

The effects of nonlinear energy sink and piezoelectric energy harvester on aeroelastic instability of an airfoil

2021 ◽  
pp. 107754632199358
Author(s):  
Ali Fasihi ◽  
Majid Shahgholi ◽  
Saeed Ghahremani
Keyword(s):  
Energy Harvester ◽  
Equations Of Motion ◽  
Continuation Method ◽  
Dynamical Behavior ◽  
Harmonic Balance Method ◽  
Nonlinear Energy Sink ◽  
Piezoelectric Energy ◽  
Energy Sink ◽  
Two Degree Of Freedom ◽  
Nonlinear Energy

The potential of absorbing and harvesting energy from a two-degree-of-freedom airfoil using an attachment of a nonlinear energy sink and a piezoelectric energy harvester is investigated. The equations of motion of the airfoil coupled with the attachment are solved using the harmonic balance method. Solutions obtained by this method are compared to the numerical ones of the pseudo-arclength continuation method. The effects of parameters of the integrated nonlinear energy sink-piezoelectric attachment, namely, the attachment location, nonlinear energy sink mass, nonlinear energy sink damping, and nonlinear energy sink stiffness on the dynamical behavior of the airfoil system are studied for both subcritical and supercritical Hopf bifurcation cases. Analyses demonstrate that absorbing vibration and harvesting energy are profoundly affected by the nonlinear energy sink parameters and the location of the attachment.

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.

Measurements and Modeling of Ingress in a New 1.5-Stage Turbine Research Facility

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Marios Patinios ◽  
James A. Scobie ◽  
Carl M. Sangan ◽  
J. Michael Owen ◽  
Gary D. Lock
Keyword(s):  
Theoretical Model ◽  
Gas Turbines ◽  
Test Facility ◽  
Radial Clearance ◽  
Operating Life ◽  
The Core ◽  
Wide Range ◽  
Purge Flow ◽  
Rotor Disk ◽  
Engine Components

In gas turbines, hot mainstream flow can be ingested into the wheel-space formed between stator and rotor disks as a result of the circumferential pressure asymmetry in the annulus; this ingress can significantly affect the operating life, performance, and integrity of highly stressed, vulnerable engine components. Rim seals, fitted at the periphery of the disks, are used to minimize ingress and therefore reduce the amount of purge flow required to seal the wheel-space and cool the disks. This paper presents experimental results from a new 1.5-stage test facility designed to investigate ingress into the wheel-spaces upstream and downstream of a rotor disk. The fluid-dynamically scaled rig operates at incompressible flow conditions, far removed from the harsh environment of the engine which is not conducive to experimental measurements. The test facility features interchangeable rim-seal components, offering significant flexibility and expediency in terms of data collection over a wide range of sealing flow rates. The rig was specifically designed to enable an efficient method of ranking and quantifying the performance of generic and engine-specific seal geometries. The radial variation of CO2 gas concentration, pressure, and swirl is measured to explore, for the first time, the flow structure in both the upstream and downstream wheel-spaces. The measurements show that the concentration in the core is equal to that on the stator walls and that both distributions are virtually invariant with radius. These measurements confirm that mixing between ingress and egress is essentially complete immediately after the ingested fluid enters the wheel-space and that the fluid from the boundary layer on the stator is the source of that in the core. The swirl in the core is shown to determine the radial distribution of pressure in the wheel-space. The performance of a double radial-clearance seal is evaluated in terms of the variation of effectiveness with sealing flow rate for both the upstream and the downstream wheel-spaces and is found to be independent of rotational Reynolds number. A simple theoretical orifice model was fitted to the experimental data showing good agreement between theory and experiment for all cases. This observation is of great significance as it demonstrates that the theoretical model can accurately predict ingress even when it is driven by the complex unsteady pressure field in the annulus upstream and downstream of the rotor. The combination of the theoretical model and the new test rig with its flexibility and capability for detailed measurements provides a powerful tool for the engine rim-seal designer.

A closed-loop wide-range tunable mechanical resonator for energy harvesting systems

2009 ◽  
Vol 19 (9) ◽  
pp. 094004 ◽  
Author(s):  
Christian Peters ◽  
Dominic Maurath ◽  
Wolfram Schock ◽  
Florian Mezger ◽  
Yiannos Manoli
Keyword(s):  
Energy Harvesting ◽  
Closed Loop ◽  
Mechanical Resonator ◽  
Wide Range ◽  
Harvesting Systems

scholarly journals The effect of non-uniform damping on flutter in axial flow and energy-harvesting strategies

2012 ◽  
Vol 468 (2147) ◽  
pp. 3620-3635 ◽  
Author(s):  
Kiran Singh ◽  
Sébastien Michelin ◽  
Emmanuel De Langre
Keyword(s):  
Theoretical Model ◽  
Energy Harvesting ◽  
Axial Flow ◽  
Flexible Structure ◽  
Fluid Loading ◽  
Power Harvesting ◽  
Reduced Order ◽  
Slender Structure ◽  
Preliminary Study ◽  
System Energy

The problem of energy harvesting from flutter instabilities in flexible slender structures in axial flows is considered. In a recent study, we used a reduced-order theoretical model of such a system to demonstrate the feasibility for harvesting energy from these structures. Following this preliminary study, we now consider a continuous fluid-structure system. Energy harvesting is modelled as strain-based damping, and the slender structure under investigation lies in a moderate fluid loading range, for which the flexible structure may be destabilized by damping. The key goal of this work is to analyse the effect of damping distribution and intensity on the amount of energy harvested by the system. The numerical results indeed suggest that non-uniform damping distributions may significantly improve the power-harvesting capacity of the system. For low-damping levels, clustered dampers at the position of peak curvature are shown to be optimal. Conversely for higher damping, harvesters distributed over the whole structure are more effective.

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