Performance Of Vibration Energy Harvester Research Articles

Design and optimization of quasi-zero-stiffness dual harvester-absorber system

The single quasi-zero-stiffness harvester-absorber system has shown its effectiveness in harvesting vibration energy and suppressing low-frequency vibrations simultaneously. Nevertheless, drawbacks of narrow frequency range of vibration suppression and low output power are still challenges. In this paper, a novel quasi-zero-stiffness dual harvester-absorber system (QZS DHAS) is proposed for broadband synergistic vibration suppression and energy harvesting at low frequency. The QZS feature is realized by mounting an equal-strength piezoelectric beam and a pair of magnet rings in parallel. Firstly, the restoring force of both the piezoelectric beam and the magnet rings are theoretically derived, respectively, which are verified by finite element simulations. Then, the governing equations of a host oscillator with QZS DHAS are derived based on Newton's law and Kirchhoff's law, which are solved by the harmonic balanced method combined with the pseudo arc-length continuation method. Moreover, the effects of mass ratios, frequency ratios and damping ratios on the performance of the QZS DHAS are investigated in details. Finally, the parameters of the QZS DHAS are optimized to improve the performance of vibration suppression and energy harvesting by using the multi-objectives genetic algorithm in combination with the technique of establishing order preference by similarity to the ideal solution. The results show that the peak response of the host oscillator is reduced by 33.48 % and the peak power is increased by 531.38 % after optimization, which indicates that the dual objectives of broadband vibration absorption and high-efficiency energy harvesting are fulfilled.

Parameter Analysis of Vibration Damping and Energy Harvesting Performance of Bionic Suspension

The traditional damping structure usually transfers the vibration energy into heat, dissipated and without harvesting. But for harsh environments, such as military activities and lunar probe patrols, the vibration energy can be extracted, and realize the purpose of self-power condition monitoring. In this paper, a bionic suspension with energy-harvesting property is proposed based on bionic configurations. The bionic suspension adopts a symmetrical three-link arrangement to simulate the arrangement of bones, and a horizontal spring to simulate muscles. The micro-generator embedded in the knee joint provides the main damping force for the overall structure and also plays a role in harvesting energy. The dynamic equation and virtual prototype model are established, and the effects of parameter changes on the performance of vibration reduction and energy harvesting are analyzed, and the relationship between the two is revealed. The results show that the parameters to achieve their respective optimal performance are not consistent in the trend, though it is difficult to obtain the best performance of both, it can be designed according to the specific functions to be satisfied. This structure can be utilized as a general model for vibration reduction and energy harvesting scenarios, providing new ideas for self-powered sensing and condition monitoring configurations.

The optimal design of wind-induced vibration energy harvester with microscale and high efficiency

Abstract In order to improve the performance of wind-induced vibration energy harvester (WIV-EH), the bluff body and cantilever beam play a significant role when the energy harvester works. In this paper, a WIV-EH model is designed to explore the factors affecting energy capture efficiency. In the Optimal design of bluff body, five kinds of bluff body is set to analyse the influence of the shape on the lift and lift coefficient by COMSOL Multiphysics 6.0. According to the simulation results, the D-shaped bluff body is optimized by changing the scale ratio and windward surface shape. In the Optimal design of cantilever beam, the result shows that under the same bluff body and wind speed, the shape of cantilever beam will affect the magnitude and distribution of strain. we also designed cantilever beams with different materials and splicing materials, and studied the response voltage output at different wind speeds. According to the above results, a wind tunnel test was designed for verification. The research results may provide new ideas for improving the energy harvesting efficiency of energy harvesters.

Performance analysis of electromagnetic vibration energy harvester under square excitation

Harvesting energy from surrounding vibrations is an effective method for powering various low-power electronic devices. The energy output performance of vibration energy harvesters under some special excitations remains to be investigated. In this paper, a vibration energy harvester (VEH) system based on a rack and pinion mechanism and a bevel gear set is proposed, and a detailed electromechanical coupling modeling of the system under general excitation and square wave excitation is carried out. The energy output characteristics of the proposed system under square wave excitation are explored through simulation and experiment. When the energy output is the target, the priority of adjusting the constituent parameters in the equivalent mass parameter, equivalent damping parameter and equivalent stiffness parameter of the system can be obtained based on the simulation results. The experimental results under periodic square wave excitation force show that the maximum output power of the proposed system is 2.7 W at an amplitude of 4 kN and a frequency of 3 Hz. This is a 55 % increase in the maximum power compared to the sinusoidal excitation under the same conditions. It is demonstrated that the proposed system has great potential to power various low-power electronic devices.

Suppressing friction-induced stick-slip vibration through a linear PZT-based absorber and energy harvester

AbstractIn this paper, a PZT (lead zirconate titanate)-based absorber and energy harvester (PAEH) is used for passive control of friction-induced stick-slip vibration in a friction system. Its stability condition coupled with PAEH is analytically derived, whose efficiency is then demonstrated by numerical simulation. The results show that the structural parameters of the PAEH can significantly affect the system stability, which increases with the mass ratio between the PAEH and the primary system, but first increases and then decreases with the natural frequency ratio between the PAEH and the primary system. The impacts of the electric parameters of the PAEH on the system stability are found to be insignificant. In addition, the PAEH can effectively suppress the stick-slip limit cycle magnitude in a wide working parameter range; however, it does not function well for friction systems in all the working conditions. The stick-slip vibration amplitude can be increased in the case of a large loading (normal) force. Finally, an experiment on a tribo-dynamometer validates the findings of the theoretical study, in which the vibration reduction and energy harvesting performance of the PAEH is fully demonstrated.

Cross-well dynamics for vibration energy harvesting of base-excited antisymmetric bi-stable laminate with a point being fixed

The cross-well dynamic of the bi-stable laminates triggered by ambient vibration is a typical nonlinear dynamic, the larger deformation makes the bi-stable laminates attract much attention in vibration energy harvesting. To obtain the performance of cross-well dynamics and vibration energy harvesting of the bi-stable laminate theoretically, a 4-layer harmonic base-excited antisymmetric cross-ply bi-stable laminates with d31 type Marco fiber composite (MFC) for vibration energy harvesting is proposed. The bi-stable laminate is fixed at a chosen point where a base excitation is applied as displacement excitation. The first order shear deformation laminated plate theory (FSDT), geometric nonlinear, and the energy principle are employed to obtain the governing equation of the system in terms of the polynomial coefficients of configuration functions. Two stable configurations are calculated by the principle of minimum potential energy, which is used as the initial state for the energy harvesting analysis. The stable configurations are predicted, and evaluated by comparing them with ABAQUS. The cross-well nonlinear dynamic behaviors and the performance of energy harvesting are analyzed. The effects of excitation level, excitation frequency, and the position of the fixed point on the cross-well dynamics and energy harvest characteristics of the antisymmetric bi-stable laminates are investigated in-depth, and some new aspects are revealed. It demonstrates that the base displacement harmonic excitation can induce chaotic cross-well vibration in a high-frequency band when the fixed point is far away from the center point, the various cross-well vibration of the system is more likely to occur in the dominate-frequency resonant band.

Analytical solution and optimal design for the output performance of Galfenol cantilever energy harvester considering electromechanical coupling effect

The theoretical model of a Galfenol cantilever energy harvester is investigated for vibration energy harvesting. Compared with the numerical solution, the analytical solution can better capture the intrinsic effects of the physical parameters on the performance of the harvester. In this work, an electromechanical coupled distributed-parameter model of the Galfenol cantilever energy harvester is established based on Hamilton’s principle, linear constitutive equations of magnetostrictive material, and Faraday’s law of electromagnetic induction. The definitions and expressions of the electric damping and modified frequency are proposed due to the electromechanical coupling. The explicit analytical expressions of the average harvested power across the load resistance and tip vibration displacement of the Galfenol energy harvesting model are derived using the methods of Galliakin decomposition and electromechanical decoupling. The accuracy of the derived analytical results is verified by the experimental data and numerical solutions. The vibration response and energy harvesting performance of the Galfenol energy harvesting model are investigated by varying the excitation frequency, external resistance, and excitation acceleration amplitude. The analytical results show that, with the increase of the external load resistance and excitation frequency, the harvested power increases first and then decreases, indicating the existence of the optimal resistance and excitation frequency. From the explicit analytical expressions of the average harvested power, the optimal external load resistance or excitation frequency could be easily found to achieve the maximum harvested power for any fixed excitation frequency or external load resistance. The concept of proposing the electric damping and modified frequency for the Galfenol cantilever energy harvester simplifies the solution process for the output performances benefiting from the exact relationship between the output performances and the electromechanical coupling parameter derived in this work.

Dynamics and performance evaluation of wind-induced vibration of a cuboid bluff body with two ornaments

The geometric design of the bluff body has a decisive effect on the wind-induced vibration energy harvesting performance. Aiming to enhance the properties of the wind-induced vibration energy harvester at the low-speed wind, we presented a wind-induced vibration energy harvester with two symmetrical additional ornaments, and the effects of installation location and size of ornaments on a cuboid bluff body are comprehensively studied. A distributed parameter model is developed based on the Euler-Lagrange equation. Corresponding numerical simulation and wind tunnel tests are implemented to evaluate the dynamics and performance of wind-induced vibration. The results show that the wind-induced vibration energy harvesters with various bluff bodies may exhibit galloping or vortex-induced vibrations (VIV) based on the position of ornaments and h/DB (h is the height of the ornament and DB is the diameter of the cuboid bluff body. For both Square-Front-h/DB (S–F-h/DB) and Square-Middle-h/DB (S-M-h/DB), the aeroelastic energy harvesting performance and the root-mean-square output voltage (Vrms) are improved in the low-speed wind. Compared with the cuboid bluff body, the critical wind speed (the smallest wind speed for triggering vibration) of S-M-0.25 is reduced by 18.18%, and the maximum voltage output reaches 10.89 V, which is increased by 105.72%. Afterwards, the three-dimensional computational fluid dynamics (3D-CFD) studies are conducted by Xflow to investigate the inherent physical mechanism of performance improvement. The results of vorticity vectors and vorticity contours verify the experimental results and reveal the insight mechanism of aerodynamic change. This work could provide a theoretical basis for optimizing wind-induced vibration energy harvesters and improving the performance of aeroelastic energy harvesting.

Electromechanical model and simple numerical analysis for a piezoelectric vibration energy harvester considering nonlinear piezoelectricity, nonlinear damping, and self-powered synchronized switch circuit

Establishment of an analytical technique that considers nonlinear piezoelectricity, nonlinear damping, and the connections to the self-powered synchronized switch circuit represents a challenging but practical issue in the development of piezoelectric vibration energy harvesters. The two-way coupled analysis method, which combines numerical software with a circuit simulator, can simulate the performance of the harvester, but it imposes a high computational load. We develop a numerical analysis technique that is more readily implemented to allow us to produce accurate predictions of the output power, displacement, and frequency response characteristics of this harvester with the switch circuit. First, we derive the electromechanical equation required for the miniature harvester, and we then determine the parameters in this equation using the harmonic balance method. Finally, the governing equation coupling the piezoelectric vibration energy harvester with the self-powered synchronized switch circuit is simplified, taking the form of a quartic equation with respect to the displacement. The simulation replicated a reduction in the displacement at higher resistive loads, wider variations in the resonance frequency, and the nonlinear stiffness softening characteristics that were observed experimentally. This paper provides a practical method for predicting the performance of the nonlinear piezoelectric vibration energy harvester with the synchronized switch circuit.

Integrated a nonlinear energy sink and a piezoelectric energy harvester using simply-supported bi-stable piezoelectric composite laminate

A nonlinear device is presented for simultaneous vibration absorption and energy harvesting. This device is composed of a nonlinear energy sink and a piezoelectric energy harvester (NES-EH), and its core component is the simply-supported bi-stable piezoelectric composite laminate (BPCL). Its outstanding advantages are light weight, simple and reliable structure. The theoretical model is developed to model a harmonically excited linear oscillator coupled with NES-EH. The Runge–Kutta method and the harmonic balance method (HBM) are used to solve the theoretical model numerically and analytically. The vibration suppression efficiency is utilized to quantify the vibration absorption performance, while the energy harvesting performance is assessed by bandwidth for energy harvesting and maximum voltage within the bandwidth. The effects of the excitation amplitude, the concentrated mass of NES-EH, the length and width of BPCL, and the load resistance are considered on the performances of NES-EH. The vibration absorption and energy harvesting performances of NES-EH can be improved by adjusting these parameters. In addition, the proposed NES-EH can achieve the goal of higher power density and normalized power density under low-amplitude excitation and simultaneously have a good vibration absorption effect. Finally, approximate analytical solutions are obtained by using HBM to exhibit various bifurcations and singularities.

Experimental and numerical study on 2-DOF wind-induced vibration and energy harvesting of triangular prism

The two-degrees of freedom (2-DOF) wind-induced vibration (WIV) response and energy harvesting performance of an equilateral triangular prism were conducted by numerical and experimental studies under different attack angles. The piezoelectric patch is applied in this work to extract power. To enhance the output power of the prism, an omnidirectional piezoelectric system is used to harvest energy in flow and cross flow directions simultaneously. It's found that the attack angle (α0) is a key factor influencing the power extraction performance of the system. The output power of the prism almost keeps around zero when 0° ≤ α0 ≤ 30° and increases monotonously with the increase of wind velocity for 30° < α0 ≤ 60°. Especially for α0 ≥ 55°, the power output experiences a rapid increase. The highest output power of 1.30 mW can be obtained when α0 = 60°. The WIV responses show that the amplitude in the direction perpendicular to incoming flow can reach 3.00b (b is the side length of the triangular cross section for the prism) when α0 = 60°. And the lock-in region can be observed in high reduced velocity range when 30° ≤ α0 ≤ 60°. In addition, due to the transition of vortex pattern from 2S to P + S for high attack angles, the unsteady aerodynamic loading acting on the prism results in strong WIV responses with high vibration amplitude, which then leads to the improvement of energy harvesting performance from WIV.

A Composite Vibration Energy-Harvesting Absorber

The significant effect of the closed-detached response on the system is often ignored by traditional vibration control and energy-harvesting devices. In this study, we design a composite vibration energy-harvesting damper by combining the lever-type nonlinear energy sink, the three-spring quasi-zero stiffness structure, and the suspended magneto-electric energy harvester. The analytical as well as the numerical solutions are obtained using the harmonic balance method combined with the arc-length extension method as well as the Runge–Kutta method, respectively. Numerical solutions support analytical solutions. The presence of the closed-detached voltage makes composite system voltage harvesting more efficient. In addition, we investigate the performance of vibration control and energy harvesting by changing the dynamic parameters of the system such as attached mass, stiffness, and fulcrum position. Finally, when compared with the traditional absorber, the proposed absorber shows great improvement either in vibration control or in energy harvesting.

Exploring nonlinear degradation benefit of bio-inspired oscillator for engineering applications

Nonlinear structure design is an indispensable link in the development of vibration isolation, energy harvesting and fault diagnosis technologies. It is also one of the most effective technical means to improve the performance of structures in engineering applications. In this study, a bio-inspired nonlinear oscillator is proposed and the benefits of nonlinear degradation in engineering applications are explored. First, the degradation bistable oscillator and high-order quasi-zero stiffness oscillator can be obtained after the degradation of the bio-inspired nonlinear oscillator. Through the amplitude-frequency analysis, it is found that the nonlinear degradation can reduce the unstable solution in the ultra-low frequency region and reduce the resonant frequency of the bio-inspired nonlinear oscillator. Therefore, the degeneration nonlinear oscillator can realize the large-amplitude inter-well motion at ultra-low frequency or low random excitation intensity. Secondly, the theory and method of vibration isolation and energy harvesting based on the nonlinear degradation mechanism are proposed, and the vibration isolation and energy harvesting performance of the oscillator under harmonic and stochastic excitations are analyzed. Finally, the use of the stochastic resonance of the degeneration bistable oscillator can greatly improve the signal-to-noise ratio, enhance the weak fault signal, and realize early fault diagnosis. The related results help to deepen the understanding of nonlinear degenerate systems and provide new technical approaches for engineering applications.

Dynamics and performance evaluation of a vortex-induced vibration energy harvester with hybrid bluff body

To investigate the influence of bluff body with a variable section on the vortex-induced vibration (VIV) energy harvesting performance, a series of hybrid cylinders are designed and a quantitative comparison is presented. The basic elements of hybrid bluff body are the D-shaped (D) and original circular-shaped cylinders (O), and the length ratio between the O-shaped part and the D-shaped part is fixed. According to the arrangement order, three kinds of hybrid bluff bodies are termed as ODO, ODODO and DOD. A distributed model is developed and the numerical simulation is carried out to verify the response. Corresponding wind tunnel experiments are conducted, and the results reveal that compared to the bluff body with a circular cylinder, the hybrid bluff bodies such as ODODO and DOD can enhance the VIV and thus increase the output significantly. Moreover, the lock-in regions with the ODODO and DOD shapes will increase by 12.5% and 62.5%, respectively. However, the results also indicate that some type of arrangement such as ODO will suppress the energy harvesting performance. Furthermore, the computational fluid dynamics method is employed to reveal the physical mechanism of flow field around the hybrid bluff body. The results show that the integration of D-shape prism in a cylinder along an axial direction could influence aerodynamics. A faster boundary layer separation occurs for the VIV energy harvesters with the hybrid cylinders of ODODO and DOD, which could improve the energy conversion efficiency from flow-induced vibrations. However, the aerodynamic force is restricted and response is suppressed as a D-shaped cylinder is sandwiched between two O-shaped cylinders.

Analysis and design of power and bandwidth of nonlinear vibration energy harvesters with hardening restoring forces

This paper presents a theoretical foundation for designing the power and bandwidth performance of an electromagnetic nonlinear vibration energy harvester with a hardening resonator. To this end, the steady-state solution derived via first-order approximation is investigated to establish a graphical approach, which gives a clear perspective on how the resonance peak point on the frequency–displacement curve is determined in terms of the excitation amplitude, nonlinear restoring force function, and other design parameters. Then, a ν-power bandwidth, a generalized version of the half-power bandwidth, is newly introduced and its approximate analytical formulation is derived. Based on the findings of the parameter study on the ν-power bandwidth, a design scheme is proposed, which begins with specifying the location of the resonance peak point that guarantees the existence of the high-energy branch under possible variations of the excitation, followed by determining the linear natural frequency that makes the ν-power bandwidth as large as reasonably possible. Design examples, assuming a specific class of hardening nonlinearity of the restoring force, are shown to demonstrate how the proposed design scheme yields vibration energy harvesters with maximized power bandwidth performance while incorporating given design requirements.

Comparative Study of Bistable Vibration Energy Harvester Using Different Elastic Boundary

This paper demonstrates a novel bistable energy harvester coupled with a nonlinear elastic boundary (NEB-BVEH). The nonlinear elastic boundary changes the dynamic response of the bistable vibration energy harvester and improves its performance by providing additional support for the inclined spring through coupled dynamics. This work considers the performance of bistable vibration energy harvesters using different elastic boundary under different excitation amplitudes, including bistable energy harvester with linear elastic boundary (LEB-BVEH) and NEB-BVEH with different horizontal spring stiffness. The comparative results show that the performance of NEB-BVEH and LEB-BVEH is approximately the same under small excitation amplitude. However, NEB-BVEH with adding horizontal springs can significantly improve performance compared to LEB-BVEH under larger excitation amplitude. Results of the investigated case show that the bandwidth of NEB-BVEH is increased by 89.31%. The output power is increased by more than 25%. A comparative study demonstrates the superiority of NEB-BVEH, which is very beneficial for energy harvesting.

Analytical modeling of a device for vibration isolation and energy harvesting using simply-supported bi-stable hybrid symmetric laminate

The bi-stable hybrid symmetric laminate (BHSL) has been investigated for vibration isolation and energy harvesting, by taking advantage of its bi-stable characteristic. A device using simply-supported BHSL is proposed to integrate these two functions. This device is called the quasi-zero-stiffness (QZS) vibration isolator with a piezoelectric element (PE). An equivalent theoretical model is developed based on the restoring force-displacement curve of BHSL. The approximate analytical solutions and direct numerical solutions are obtained by the harmonic balance method and the Runge-Kutta method, respectively. Displacement transmissibility is utilized to quantify the vibration isolation performance of this vibration isolator. The influences of the excitation amplitude, the length of BHSL, the width of BHSL and the load resistance are analyzed. The results show that adjusting these parameters can improve the vibration isolation performance and energy harvesting performance. The QZS vibration isolator with PE achieves the goal of higher power density under a low-frequency and low-amplitude excitation and simultaneously has a good vibration isolation performance.

Investigation of the optimum vibration energy harvesting performance of electrospun PVDF/BaTiO3 nanogenerator

The piezoelectric vibration energy harvesting performance of an electrospun poly(vinylidene fluoride) (PVDF)/Barium Titanate (BaTiO3) nanocomposite piezo polymer nanogenerator was investigated in this study. To obtain the highest piezoelectric output value, electrospinning was performed using four distinct solvent volume ratios of Acetone/Dimethylformamide (DMF) of 0:10, 2:8, 4:6, and 6:4 and three different PVDF weight percent polymer concentrations of 10, 15, and 20. Additionally, three distinct BaTiO3 addition weight percents of 5, 10, and 15 were investigated. The optimal concentration of PVDF (15 wt.%) was combined with a 6:4 volume ratio of Acetone/DMF to form a nanocomposite piezo polymer nanogenerator. The morphology and crystalline structure of PVDF and PVDF/BaTiO3 were analyzed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. Nanocomposite piezo polymer nanogenerator was manufactured to harvest energy from vibration. A cantilever beam was developed without a tip mass type system for piezoelectric energy harvesting tests. The highest piezoelectric power output was obtained as 0.243 μW (15 wt.% PVDF and 5 wt.% BaTiO₃), Acetone/DMF (6:4 vol./vol.)) under 10 MΩ at the 15.7 Hz resonance frequency. The morphology of electrospun nanofibers has a significant impact on the piezoelectric performance of a nanocomposite piezo polymer nanogenerator at high-amplitude vibration.

Increase output of vibration energy harvester by a different piezoelectric mode and branch structure design

In this study, we improve the performance of vibration energy harvesting by adopting a different working mode of piezoelectric material. We propose a harvester that is composed of an inverted beam and a branch structure. The branch can produce an amplified inertial force under vibration and passes it to a lead zirconate titanate (PZT) sheet. The resultant force acts on the PZT sheet as a dynamic normal force, not as a dynamic flexural one in the classical harvester. This change can increase the output significantly. First, the theoretical model is established and solved. The results show that the design can induce a super-harmonic vibration and produce a large output. Then, the validation experiments are carried out. The experimental results prove the occurrence of super-harmonic vibration and show that under weak stochastic excitation the branch structure can promote the electric output significantly. For a stochastic excitation of PSD = 0.06 g2 Hz−1, the average power of the novel harvester can reach 0.344 mW by a small PZT sheet with the dimensions of . This study may provide a novel scheme in improving the vibration energy harvesting efficiency.

Energy harvester using two-phase flow conditions

Single-phase flow-induced vibration energy harvesting approaches, such as vortex-induced vibration, galloping, and flutter, have received considerable attention from researchers in recent years. However, the challenges and potential applications of multi-phase flow-induced vibration energy harvesting have rarely been explored. To bridge the research gap in the present energy harvesting studies based on two-phase flow, we investigated in detail the mechanism and potential benefits of the fluid–structure interaction between smart structures and two fluid phases (water and air) on the vibration energy harvesting performance. A piezoelectric energy harvester using air–water two-phase flow conditions is proposed for potential multifunctional applications. A T-shaped piezoelectric cantilever was used to harvest liquid sloshing energy in the proposed structure. A fluid–structure interaction containing two fluid phases (water and air) was theoretically modelled using the arbitrary Lagrangian-Eulerian technique. The experimental results showed that a prototype of the proposed structure can be used as a smart water bottle that simultaneously performs human-motion energy collection and acts as a drinking water bottle. The prototype achieved its maximum peak-to-peak voltage value (12.08 V) at 5 km/h for powering wireless IoT (Internet of Things) nodes. Furthermore, it can be used as an energy regenerative shock absorber to perform the dual functions of vibration damping and energy harvesting. Therefore, multi-phase flow-induced vibration energy harvesting shows great application potentials.