Performance Of Vibration Energy Harvester Research Articles

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.

Performance and dynamics of a novel bistable vibration energy harvester with appended nonlinear elastic boundary

This paper proposes a novel bistable energy harvester coupled with a nonlinear elastic boundary (BEH-NB) to enhance energy harvesting performance. The analytical model of BEH-NB is derived and verified experimentally. Then the performance of the bistable energy harvester with different boundary conditions is investigated, including the bistable energy harvester with linear elastic boundary (BEH-LB), the bistable energy harvester without elastic boundary (BEH), and a linear energy harvester (LEH). The compared results show that the performance of BEH-NB is better than that of its counterparts. Results of the studied case show that the average power of BEH-NB can be improved by 42.05%, and the operational bandwidth is significantly widened by 93.18%, which is highly beneficial for energy harvesting. To identify the optimal parameters set for energy harvesting from ambient excitation, bifurcation analyses are performed. It is found that small changes in parameters can profoundly alter the system’s steady-state response. The initial conditions also have a significant effect on the type of the system’s response. Therefore, the basin of attraction of BEH-NB is calculated to reveal the influence of the initial conditions and to quantify the occurrence probability of the different types of motion. The results of this paper provide a novel perspective in the structural design of the system and offer a practical application design guidelines to improve the system’s performance.

Enhancement of Vibration Energy Harvesting Performance by Omni-Directional INVELOX Wind Funnel: A Computational Study

An alternate renewable energy source, through a piezoelectric vibration energy harvester with a bluff splitter body, could lead to higher efficiency in energy harvesting, through vortex-induced vibration at a near-resonance condition at 20 m/s high wind speed. However, wind energy is not as popular as solar energy, as the main renewable energy source in Malaysia, due to the relatively low wind speed available in the country. The INVELOX machine, introduced in 2014, was one of the most recent systems used to harvest wind power by accelerating wind speed. This omni-directional wind funnel could capture wind from all directions and tunnel it through a convergent-divergent nozzle, where the coupled bluff splitter body and piezoelectric vibration energy harvester (PVEH) are located at its venturi throat, which could lead to an increase in wind speed to fulfil the task of VIV energy harvesting. The proposed modified design is found to achieve 2.7 times the wind speed amplification at the venturi, which outperformed previously proposed designs. To achieve the optimum wind speed of 20 m/s for the coupled bluff splitter body and the PVEH plate, a free-stream wind speed of 7.4 m/s is recommended. The integration of the PVEH plate and the wind funnel is expected to harvest maximum voltage output at 20.99 V or 4.96 V, with a maximum power output of 0.82mW at 20 m/s.

Power generation performance of a bistable speed bump vibration energy harvester

A model of a bistable speed bump vibration energy harvester (BSVEH) is designed by combining the buckling beam, rack and pinion, one-way clutch and speed bump with rotor alternator. One-way clutches are used to ensure the input shaft of rotor alternator to rotate unidirectionally during the up-and-down vibration of the speed bump. The coupled mechanical model of the speed bump energy harvester is established to study the power generation performance subjected to various structural parameters, that is, types of speed bump, types of vehicles, geometrical parameters of the buckling beam, speed increasing ratio and moment of inertia. Simulations show that the output power of the BSVEH (such as 148 J in 1 second) is larger than that of the speed bump energy harvester with linear spring (86 J in 1 second). Compared with the vehicle passing over speed bump energy harvester with linear spring, the vertical and pitch accelerations of a vehicle are decreased 9.3% and 16.5%, respectively when it passes over the BSVEH. Riding quality is also improved. The effect laws of the type and speed of the vehicle speed on the output power of the BSVEH are obtained. The maximum output power of SBVEH is 14.8 W at the vehicle speed 24 km/h. The maximum energy-efficiency of the BSVEH can reach 43.9%. And the maximum average electrical power can arrive at 12.7 W. The optimal parameters favoring the output power of BSVEH are determined. The advantages of power generation and riding quality, correctness of mechanical models and effectiveness of BSVEH are verified by simulation results.

An adjustable device to adaptively realise diverse nonlinear force-displacement characteristics

The benefit of introducing nonlinear stiffness elements to improve the dynamic performance of vibration energy harvesters, vibration isolators and vibration absorbers have attracted great attention in the recent literature. A simple adjustable device to tailor nonlinear stiffness for diverse engineering applications is thus proposed in this paper. The device adopts two pairs of linear oblique springs, whose geometric arrangement can be modified to achieve specific nonlinear force-displacement characteristics. Depending on its design configuration, it is able to be adapted and behave as linear, hardening, softening, quasi-zero stiffness for large deflections, quasi-zero stiffness for small deflections, bi-stable and tri-stable. The design strategy and the main parameters involved are discussed.

Effect of magnetic field on output performance of magnetic liquid vibration energy harvester

PurposeThe purpose of this study is to develop a friction-type energy-harvesting device based on magnetic liquids (MLs). This MLs energy-harvesting device combines MLs with a triboelectric nanogenerator (TENG), reducing the friction thermal effect to improve the conversion efficiency and working frequency band.Design/methodology/approachFirst, the motion equation of the MLs is calculated using the Bernoulli and fluid continuity equations. Second, the sloshing process of an ML in a container is simulated using the finite element simulation method, and the magnetic field distribution of the permanent magnet in the MLs is calculated. Then, the output characteristic of the ML-TENG is deduced theoretically, and the influencing factors of the output voltage are analyzed. Finally, the output voltage of the MLs energy-harvesting device was tested experimentally, and the influence of the magnetic field on the output voltage was tested.FindingsThis study proposes a vibration energy harvesting device based on MLs. The output voltage of the device was obtained through simulation and experimental tests, and the effect of the magnetic field on the output voltage was obtained.Originality/valueThis study provides a method to convert vibration energy into electrical energy using the magnetic response and fluid characteristics of MLs, and the availability of the device is verified by simulation and experiment. This energy-harvesting device exhibits less loss and a more sensitive response.

Promote performance of vibration energy harvesting by amplified inertial force and clamped piezoelectric beams

In this study, a novel vibration energy harvester is proposed, in which the amplified inertial force of a mass acts on two clamped piezoelectric beams to make them execute large-amplitude vibrations densely and produce large outputs. The harvester is composed of an inertial mass, two linkages and two clamped beams. Under excitation, the inertial force generated by the mass can be amplified by the linkages and make the clamped beams deflect easily. Especially, the beam will deflect four times in a cycle, thus it can produce the pulse voltage densely. The theoretical model is established and corresponding simulations are carried out. The validation experiment was conducted. For a low-frequency excitation, the piezoelectric beam can be driven to oscillate with many super-harmonic components, this can increase the electric output in a period. The random experiments prove that the harvester could produce a fairly large output under weak excitation. For the excitation of PSD = 0.06 g2/Hz, it can generate a root-mean-square power of 0.115 mW through a PZT layer of 25 mm × 10 mm.

Nonlinear 1:2 internal resonance response of L-shaped piezoelectric energy harvester under the influence of electrical damping

The internal resonance mechanism is widely used to improve the output performance of vibration energy harvester owing to its modal interaction between modes. The electromechanical-coupled theoretical model has been verified by experiments in our previous work (Nie et al., 2019). The approximate analytical solutions of the electromechanical-coupled governing equations of the harvester are derived using the method of multiple scales, and verified by the numerical method. The equilibrium stability of the output responses are determined by the eigenvalues of Jacobian matrix of the modulation equations. The effects of load resistance on electrical damping, natural frequency and primary resonance responses of the harvester are investigated. The results show that the harvested power is associated with the electrical damping caused by the load resistance. The threshold of the excitation amplitude that triggers the internal resonance from the perspective of load resistance are investigated. Under the influence of load resistance and excitation amplitude, the saturation phenomenon, jumping phenomenon, softening phenomenon, Hopf bifurcation and saddle–node bifurcation are explored. The results indicate that the internal resonance responses of the harvester vary with the excitation amplitude and load resistance, and jump between the upper and lower branches depending on initial displacement.

A novel soft encapsulated multi-directional and multi-modal piezoelectric vibration energy harvester

Advances in the design of various piezoelectric vibration-based energy harvesters (PVEHs), as a kind of power devices that can convert ambient energy to useable electrical energy, have become a hot topic in recent years due to their potential perspectives in wireless sensor networks, wearable electronics and low-power microelectronics. Unfortunately, conventional PVEHs modelled by beam- or plate-type planar structures are mainly restricted to harness kinetic energy in a single direction only. However, ambient vibration sources often work in multiple directions and broadband frequencies. To address this challenging problem, a mechanically-guided three-dimensional (3D) assembly structure is strategically designed to construct a soft cruciform-encapsulated PVEH in this work. Meanwhile, a reliable soft encapsulation technology is introduced to maintain the 3D configuration, which not only can avoid the collapse problem and also improve the dynamical performance. The entire system consists of a compressive buckling cruciform structure with a proof mass, PVDF thin film, and soft encapsulation. The dynamic characteristics of the system can be adjusted by changing the structural parameters, such as the pre-stressing force of the pre-stretched elastic substrate and the quality of the additional mass block. Finite element analysis and experimental studies are conducted to investigate the modal characteristics of system. A comparison of the vibration energy harvesting performance between the encapsulated and unencapsulated piezoelectric harvesters is presented. The results demonstrate that the encapsulated one can work well under multi-directional, multi-modal and low-frequency conditions. A maximum power output of 9.8 mW in the frequency range of 1–200 Hz can be achieved, which is almost 560 times more than that of the unencapsulated one. The proposed methodology also offers a new perspective for the fabrication design of soft-type PVEHs with higher working performance.

Investigation of boundary flexibility on the performance of piezoelectric vibration energy harvesting beam systems by DTFM

The purpose of this paper is to investigate the effect of boundary flexibility on the performance of piezoelectric vibration energy harvester (PVEH) beam systems, which has not been studied comprehensively in the literature despite its importance. The coupled electromechanical equations of motion of a piezoelectric cantilever beam with a tip mass are established, with the base boundary constrained by translational and rotational springs. An exact closed-form solution of the frequency response function (FRF) of the PVEH is obtained by the distributed transfer function method (DTFM). The DTFM is a systematic powerful tool for the dynamic analysis of distributed parameter continua with non-classical boundary conditions, intermediate constraints, coupled fields, and non-proportional damping without adding much complexity to the solution formulation. Moreover, the DTFM computes the derivatives of the response, that is, the strains, which are required in the electromechanical coupling formulation, simultaneously without any differentiation. Numerical results showing the effects of boundary flexibility on energy harvesting efficiency are presented. A first-order rational function relating the boundary stiffness parameters and the harvesting efficiency is determined by nonlinear curve fitting of the calculated data. Physical insights and applicability of this analytical function for end-of-line quality check of the boundary of PVEH are discussed.

Performance of Fe–Ga alloy rotational vibration energy harvester with centrifugal softening

With the development of vibration energy harvesting, sensor nodes for wireless monitoring are being increasingly powered by harvesting vibrations in rotating environments such as car tires and fan blades. Considering the diverse installation positions of vibration energy harvesters on rotating carriers, the centrifugal forces of the cantilever beams exhibit remarkable differences during rotation. Crucial factors for the performance of vibration energy harvesting include the deformation of the harvester cantilever beam, which is affected by the centrifugal force, and the influence of the pre-magnetization field on the Villari effect of specific alloys. We propose a rotational vibration energy harvester based on an Fe–Ga alloy and establish a mathematical model for magnetostrictive vibration energy harvesting by leveraging centrifugal softening. In addition, we perform a systematic theoretical analysis of the factors influencing the harvester performance considering centrifugal softening, rotation radius, and arrangement of the pre-magnetization field. The theoretical findings are verified on a prototype, and the system characteristics are investigated experimentally. The maximum output voltage reaches 3.36 V, and the energy harvesting efficiency reaches 22.86% when the harvester undergoes rotation at 330 r min−1. Moreover, the harvester is applied in a low-power temperature sensor for real-time temperature monitoring, indicating the validity and applicability of the proposed rotational vibration energy harvester. The results demonstrate that an appropriate use of the centrifugal softening and the pre-magnetization field can enhance the energy harvesting efficiency of a harvester operating at a low rotational frequency.

On the investigation of ash deposition effect on flow-induced vibration energy harvesting

This paper proposes harnessing the aerokinetic energy in flue systems and it explores the ash deposition effect on flow-induced vibration energy harvesting performance. Bell-shaped and horn-like bluff bodies are designed to simulate different ash depositions on a conventional elliptic cylinder bluff body. Wind tunnel experiments were conducted to investigate the energy harvesting performance using different ash depositions distributed over the bluff bodies. The experimental results show that compared to the baseline model of a conventional elliptic cylinder bluff body, the bell-shaped bluff body suppresses the flow-induced vibration and deteriorates the energy harvesting performance. In contrast, the horn-like bluff body can benefit energy harvesting by reducing the galloping cut-in wind speed and increasing the voltage output. The voltage output of an optimal prototype using the horn-like bluff body is increased by 516%. Computational fluid dynamics (CFD) simulations were carried out to unveil the physical mechanisms behind the phenomena. The CFD analysis results indicate that the appearance of the small-scale secondary vortices (SV) widens the wake flow and increases the aerodynamic force produced by the horn-like bluff body. The flow-induced vibration of the harvester using the horn-like bluff body transforms from VIV to galloping. Therefore, it has been preliminarily demonstrated that the unfavorable ash deposition phenomenon in flue systems has the potential for promoting flow-induced vibration energy harvesting.

Improving the Electromagnetic Vibration Energy Harvester Performance by Using a Double Coil Structure

The power generation capability of an electromagnetic vibration energy harvester augmented with an additional coil was investigated and compared with that of a standard single coil electromagnetic energy harvester. A single degree of freedom model and the corresponding equivalent electric circuit were employed for the analysis of the standard and of the augmented harvesters. The harvester model was validated by means of an accurate experimental characterization of a commercial electromagnetic harvester, i.e., the model-D by ReVibe. The electric circuits for the standard and for the augmented harvesters were implemented by electronic components and experimentally tested to determine the maximum power they are able to generate in four test conditions. Results from simulations and from experiments showed significant improvement of the power extraction performance exhibited by the double coil energy harvester, particularly at frequencies lower than the harvester mechanical resonance frequency.

A micro-electromagnetic vibration energy harvester with higher power density and wider bandwidth utilizing 3D MEMS coils

In this study, the performance of an electromagnetic vibration energy harvester (EM-VEH) based on micro-electro-mechanical systems 3D coils was presented theoretically and experimentally. The VEH employs two 3D coils and E-shape iron cores inserted into the coils to reduce the magnetic leakage and to improve the output power. In this structure, the planar spring stiffness and the attraction between the iron core and magnet are nonlinear, which can broad the bandwidth. In the theoretical work, a magnetic dipole model with the integral form was derived to describe the nonlinear interaction and estimate the dynamic response, which agreed well with the finite element method results. The influence of load resistance, excitation acceleration, and initial magnet offset (IMO) was measured and analyzed experimentally. The results showed that the IMO had a significant influence on the output performance. The maximum output power of one coil can reach 57.65 μW for 250 μm IMO based on 1 g excitation with the normalized power density (NPD) of 5.08 μW/cm3 g2, along with a half power bandwidth of 4 Hz. For a smaller IMO of 174 μm, the output power reduced at 22.23 μW with the same excitation condition, while the half power bandwidth was broadened to 13 Hz. With the increase in excitation, the output power and bandwidth can be improved while the NPD reduces. The tested results proved that the structure proposed in this study can significantly enhance the output performance compared with published data.

Design and experiment investigation of a percussive piezoelectric energy harvester scavenging on wind galloping oscillation

In this article, a percussive piezoelectric energy harvester (PPEH) is proposed for scavenging on wind galloping oscillation. Due to galloping effect of the square oscillator, the impact beams could transfer wind galloping oscillation to the piezoelectric beams percussively, and then convert the vibration energy into electricity. The vibration response and energy harvesting performance of the PPEH are experimentally investigated with variable parameters. And the results show that there is an optimal critical wind speed to maximize the output power of the PPEH. The electrical performance of the PPEH can be improved by adding tip mass and changing the percussive position.

Nonlinear vibration energy harvesting and vibration suppression technologies: Designs, analysis, and applications

Limited by the structure, the high-efficiency vibration energy harvesting and vibration suppression have always been a theoretical bottleneck and technical challenge in this field. The nonlinear design of the new vibration structure is an indispensable link in the development of vibration energy harvesting and vibration suppression technologies. Nonlinear technologies not only have the potential to improve the efficiency of the energy harvesters by increasing the useful frequency bandwidth and output power but also have the potential to improve the efficiency of vibration suppressors by reducing the transmission rate and transfer energy. Nonlinear vibration energy harvesting and vibration suppression technologies have been salient topics in the literature and have attracted widespread attention from researchers. The present work provides a comprehensive review on the recent advances in nonlinear vibration energy harvesting and vibration suppression technologies. In particular, the latest developments in multifunctional hybrid technologies are proposed. Various key aspects to improve the performance of nonlinear vibration energy harvesting and vibration suppression systems are discussed, including implementations and configuration designs, nonlinear dynamics mechanisms, various optimizations, multifunctional hybrid, application prospects, and future outlooks.