Low-frequency Vibration Energy Research Articles

Simultaneous low-frequency vibration isolation and energy harvesting via attachable metamaterials

In this study, we achieved energy localization and amplification of flexural vibrations by utilizing the defect mode of plate-attachable locally resonant metamaterials, thereby realizing compact and low-frequency vibration energy suppression and energy harvesting with enhanced output performance. We designed a cantilever-based metamaterial unit cell to induce local resonance inside a periodic supercell structure and form a bandgap within the targeted low-frequency range of 300–450 Hz. Subsequently, a defect area was created by removing some unit cells to break the periodicity inside the metamaterial, which led to the isolation and localization of the vibration energy. This localized vibration energy was simultaneously converted into electrical energy by a piezoelectric energy harvester coupled with a metamaterial inside the defect area. Consequently, a substantially enhanced energy harvesting output power was achieved at 360 Hz, which was 43-times higher than that of a bare plate without metamaterials. The proposed local resonant metamaterial offers a useful and multifunctional platform with the capability of vibration energy isolation and harvesting, while exhibiting easy handling via attachable designs that can be tailored in the low-frequency regime.

Piezoelectric-electromagnetic collaborative energy extraction circuit for wearable vibration energy harvester

A piezoelectric-electromagnetic collaborative energy extraction circuit (PEC-EC) is presented in this paper to extract low-frequency vibration energy from arm swinging for wearable devices. This circuit simultaneously harvests energy from both the piezoelectric transducer (PZT) and electromagnetic coil generator (ECG). When the piezoelectric output voltage reaches its peak, the peak detection circuit becomes conductive, and the energy of the piezoelectric material is extracted at this moment. At the same time, the PEC-EC circuit can also harvest electromagnetic energy. Especially, even at low electromagnetic voltage input, the electromagnetic voltage can be extracted through the designed switch. The experimental results show that the circuit starts up only when the input voltage reaches 0.5V. The electromagnetic energy conversion efficiency can reach 53 %, and the piezoelectric energy conversion efficiency can reach 56 %. The effectiveness of collaborative extraction was also verified through experimental validation.

A method to enhance the nonlinear magnetic plucking for vibration energy harvesters

In this work, a technique to improve the magnetic plucking for frequency up-conversion in piezoelectric energy harvesters is presented. The technique involves shielded magnets with Neodymium-iron-boron alloy polarized in the opposite direction on a main magnet. The phenomenon is investigated both at the computational and at the experimental level. Subsequently, simulations on a mesoscale piezoelectric energy harvester are presented which demonstrate a gain of 17 times if the magnets are shielded in comparison with the classical plucking (i.e. without shielding). The technique finds useful applications and benefits in the field of low-speed and low-frequency vibration energy harvesting, as well as in actuation and sensing.

A broadband bistable energy harvester with self-decreasing potential barrier effect: Design, modeling and experiments

The conventional bistable energy harvester (CBEH) is difficult to break through the potential barrier for large-amplitude inter-well motion under weak excitation environments, which results in a narrow effective bandwidth. This paper proposes a bistable energy harvester with self-decreasing potential barrier effect (BEH-DPBE) for harvesting low-frequency vibrational energy. A spring is introduced to transform the fixed end of the S-type power generating beam into a movable end, while its oscillator has a dual function of dynamically reducing the potential barrier in the return trip and enhancing the potential energy in the outward trip. The characteristics of the proposed energy harvester are evaluated and analyzed by combining finite element simulations, numerical studies, and experiments. Finally, the effects of key parameters, such as the spring pre-compression, proof mass, and load resistance, are studied. In low-frequency conditions, the effective bandwidth and peak-to-peak voltage of BEH-DPBE are 6.35 Hz (5.98–12.33 Hz) and 10.1 V, respectively. The proposed BEH-DPBE can effectively capture energy in low-frequency ambient vibrations.

Low-frequency multiple topological interface modes in metamaterial beams with quasi-zero-stiffness resonators

To achieve multiple low-frequency topological interface modes (TIMs) while maintaining lightweight and load-bearing capacities in metamaterial beams, we propose novel topological beams equipped with double quasi-zero-stiffness (QZS) resonators. Following the introduction of the negative stiffness (NS) mechanism, we derived the dispersion relations of the topological beams with double QZS resonators using the transfer matrix method (TMM), and performed comparative and parametric analyses of stiffness ratio on folded Dirac cones (DCs) and locally resonant band gaps (LRBGs). Thanks to the NS mechanism and the double degrees of freedom (DOFs) in the QZS resonators, we can realize double low-frequency DCs (< 500 Hz) in metamaterial beams. It is notable that adjusting the stiffness of oblique springs can tune the resonators’ effective stiffness, implying that we can custom the frequency of DCs and LRBGs by adjusting the QZS resonator. By altering the distance between two QZS resonators, we obtain two topologically distinct unit cells. Transmission simulations confirm the presence of multiple low-frequency TIMs at the interface between these two domains. We also find that the effect of mass and geometric defects at various positions on TIMs is minimal. The proposed metamaterial beams could inspire innovative low-frequency vibration energy harvesters and lightweight topological devices.

An omnidirectional low-frequency wave vibration energy harvester with complementary advantages of pendulum and gyroscope structures

To address the challenge of omnidirectional low-frequency wave vibration energy harvesting, this paper proposes a wave vibration energy harvester that combines a pendulum structure with a gyroscope structure. The Euler-Lagrange equation of the harvester kinematic model is established and solved to confirm its complementary advantages. The pendulum structure initiates the rotation of the magnetic levitation flywheel through the gears, and directs the flywheel precession to achieve a greater gyroscopic torque. The gyroscope structure generates gyroscopic torque, which helps the pendulum structure easily pass-through positions where the mass torque is small. The two structures work together to overcome the electromagnetic damping and generate electricity. This increases the power output and power density. An experimental platform for wave simulation is built to test the energy harvester. The results show that at a frequency of 1 Hz and an amplitude of ±20°, the average power output of the energy harvester is 67.51 mW when the load is 910 Ω, and the flywheel speed is 899.51 rpm. This is of great significance for the application of self-powered wireless sensors in smart ocean.

A low-frequency pure metal metamaterial absorber with continuously tunable stiffness

To address the incompatibility between high environmental adaptability and deep subwavelength characteristics in conventional local resonance metamaterials, and overcome the deficiencies in the stability of existing active control techniques for band gaps, this paper proposes a design method of pure metal vibration damping metamaterial with continuously tunable stiffness for wideband elastic wave absorption. We design a dual-helix narrow-slit pure metal metamaterial unit, which possesses the triple advantage of high spatial compactness, low stiffness characteristics, and high structural stability, enabling the opening of elastic flexural band gaps in the low-frequency range. Similar to the principle of a sliding rheostat, the introduction of continuously sliding plug-ins into the helical slits enables the continuous variation of the stiffness of the metamaterial unit, achieving a continuously tunable band gap effect. This successfully extends the effective band gap by more than ten times. The experimental results indicate that this metamaterial unit can be used as an additional vibration absorber to absorb the low-frequency vibration energy effectively. Furthermore, it advances the metamaterial absorbers from a purely passive narrowband design to a wideband tunable one. The pure metal double-helix metamaterials retain the subwavelength properties of metamaterials and are suitable for deployment in harsh environments. Simultaneously, by adjusting its stiffness, it substantially broadens the effective band gap range, presenting promising potential applications in various mechanical equipment operating under adverse conditions.

Jellyfish-inspired bistable piezoelectric-triboelectric hybrid generator for low-frequency vibration energy harvesting

In pursuit of enhancing the output power of energy harvesters, this paper introduces a novel jellyfish-inspired bistable piezoelectric-triboelectric hybrid generator (JIB-PTHG) with low potential energy barrier characteristics and low-frequency, broadband energy harvesting capabilities. The JIB-PTHG comprises two flexible beams, and two rigid links, connected via a spring. Utilizing the harmonic balance method and Runge-Kutta fourth-order algorithm, a comprehensive analysis of the mechanical properties of the low-barrier bistable structure is conducted. Static equilibrium bifurcation and dynamic response analysis are performed. Subsequently, an electromechanical coupling model incorporating piezoelectricity and triboelectricity is developed to theoretically predict the output voltage of the two modules, revealing a positive correlation between displacement and output voltage. Experiment validation demonstrated that adjusting the length of the rigid links can effectively increase the deformation of the piezoelectric beam and the relative displacement of the triboelectric layers, thus improving the generator's output performance. Specifically, the TENG module exhibited exceptional energy harvesting performance within the frequency range of 3.5–6.5 Hz, achieving a voltage of 1050 V, a power of 1.84 mW, and the ability to illuminate 70 LED lights under an excitation amplitude of 17.5 mm and a frequency of 5.5 Hz. The PEG module, displayed high output performance within the frequency range of 4-7 Hz, reaching a voltage of 6.2 Vs and a power of 12.8 μW at an excitation frequency of 7 Hz and an amplitude of 17.5 mm. Both theoretical and experimental findings indicate that the JIB-PTHG has achieved improved output power within the frequency range of 3.5–6.5 Hz. Furthermore, the JIB-PTHG has the potential to harness bridge vibration energy and convert it into useful electrical energy for powering wireless sensor nodes in bridge health monitoring systems.

Low Frequency Vibration Energy Harvesting of Piezoelectric Vibration Systems with an Adjustable Device and Inertial Amplifier Device

Low Frequency Vibration Energy Harvesting of Piezoelectric Vibration Systems with an Adjustable Device and Inertial Amplifier Device

Design a low-frequency vibration energy harvesting device based on a square spiral beam local resonant phononic crystal

Self-powered miniature wireless sensors play a crucial role in Internet of Things technology. Harvesting low-frequency environmental vibrations to achieve self-powering of sensors is a current hot topic in research. In this study, a square spiral beam local resonant phononic crystal is designed for low-frequency vibrational energy harvesting. Initially, the bandgap and vibrational modes of an ideal phononic crystal at infinite period are analyzed by the finite element method; the possibility of using the structure to harvest vibrational energy is explored. Subsequently, a PnC plate model with a unit cell is built, and its vibrational modes are analyzed, verifying that it possesses similar vibrational properties. Following this, a piezoelectric vibration energy harvesting device is assembled and its energy harvesting performance is analyzed. Numerical simulations indicate that the designed device can achieve a maximum power density of 52.14 μW/cm2. Physical experiments validate the excellent energy harvesting performance of the device. The device offering a new option for designing self-powered devices for wireless miniature sensors.

High efficiency active rectifier with low-power self-biased comparator for low-frequency piezoelectric vibration energy harvesting of AUV

This paper proposes an Active Rectifier for low-frequency vibration piezoelectric (PZE) energy harvesting of Autonomous Underwater Vehicle (AUV). By using the cross-coupled NMOS transistors and active driven PMOS transistor, the turned-on resistance across the transistors could be minimized such that the voltage conversion efficiency is improved. Besides, the problem of the reverse current is avoided. Moreover, the novel self-biased low power comparator operated in subthreshold region is employed to reduce the power consumption. Only 6 MOS transistors and 1 resistor are required in the proposed self-biased comparator. The proposed design is implemented with a 0.18μm HV process. Based on the measurement results, the peak voltage conversion efficiency (VCE) and the peak power conversion efficiency (PCE) are 97.63% and 96.26%, respectively, at 50 KΩ loads and 20 Hz vibration frequency. The maximum output power is 14.1 mW with the load of 1 KΩ.

Improving the performance of nonlinear isolator through triboelectric nanogenerator damper integrating energy harvesting

In order to solve the problem of integration of low-frequency vibration isolation and vibration energy harvesting, this paper proposes a novel nonlinear oscillator with triboelectric nanogenerator damper (NO-TENGD), which can realize different nonlinear characteristics of quasi-zero stiffness (QZS) and bistable by changing the length of rigid links. The mechanism of improving the isolation performance of NO-TENGD was analyzed and discussed with a dynamic model proposed, and the effects of excitation frequency, friction force, geometric parameters, and spring stiffness were studied. The damping can be increased by adjusting the pressure of TENGD, which can effectively suppress the resonance peak value of response amplitude and force transmissibility. The experimental results show that when the excitation frequency is larger, the amplitude response of NO-TENGD is smaller under frictionless condition, and the amplitude response of NO-TENGD under large friction condition is smaller than that under small friction one. NO-TENGD with QZS has a good vibration isolation effect, and the output power can light up 50 LED lights or electronic watches. Finally, NO-TENGD with QZS can achieve low frequency vibration suppression, and increasing damping can reduce the response amplitude and force transmissibility of the beam bridge in the resonance frequency range.

Electromagnetic Energy Harvester Based on Bidirectional Vibration to Unidirectional Rotation Conversion for Environmental Low-Frequency Vibration Energy Harvesting

Electromagnetic Energy Harvester Based on Bidirectional Vibration to Unidirectional Rotation Conversion for Environmental Low-Frequency Vibration Energy Harvesting

Nonlinear electromagnetic vibration energy harvester comprising dual helical-plane springs and multiple Halbach arrays for low-frequency and small-amplitude vibrations

Electromagnetic vibration energy harvesters are widely investigated for self-powered wireless sensors and nonlinearity has been introduced for low-frequency and broadband vibration energy harvesting. But how to realize the nonlinearity with small amplitudes, high reliability and few complexities is still a challenge in real-world applications. In this paper, a novel electromagnetic vibration energy harvester comprising dual helical-plane springs and multiple Halbach arrays is proposed. The structural characteristics are analyzed, which indicate that the helical-plane springs can have nonlinear stiffness under small-amplitude vibrations and multiple Halbach arrays can greatly enhance the magnetic field. Then a magnet-electro-mechanical model is built by combining mechanical dynamics &electrodynamics, which is numerically solved by using the Runge-Kutta algorithm. Finally, the feasibility of the nonlinear electromagnetic vibration energy harvester is validated both numerically and experimentally. The results show that it has a nonlinear stiffness, a resonance bandwidth of 3 Hz and a peak power of 14 mW when the excitation amplitude is only 0.5 g. In particular, the resonance frequency range depends on the excitation amplitude. Furthermore, the prototype of a self-powered wireless temperature sensor is constructed and testified. The results of this study indicate that the proposed structure can be utilized and extended to build compact, reliable and nonlinear electromagnetic vibration energy harvesters for low-frequency, small-amplitude and broadband vibrations in real-world applications.

Energy harvesting using magnetostrictive materials: Effects of material anisotropy and stress multiaxiality

Low-frequency vibrations are common as background noise in urban and industrial environments. They originate from natural or artificial sources: road vehicles, industrial machinery, wind, etc., and constitute a ubiquitous energy source. In the framework of energy harvesting, magnetostrictive materials are an attractive alternative solution to the brittleness and geometrical limitations of piezoelectric materials. While numerous previous works dealt with uniaxial stress on selected materials, the exploration of the effects of multiaxial loadings and material anisotropy has not yet been investigated as a way to improve the performance of low-frequency vibration energy harvesting systems. In this work, we investigated the capability of grain-oriented electrical steel in an energy-harvesting context. This material has been selected as a model material, notably as it is abundant and cost-effective. It shows limited magnetostriction but significant elastic, magnetic, and magnetostrictive anisotropy. We combined experimental and predictive simulation results to discuss the possibility of increasing the levels of harvested energy by playing with the orientation of magnetic and mechanical stimuli. Various orientations of magnetic field and mechanical stress were considered with regard to the rolling direction of the material. Unexpectedly high energy density amounts, up to 10 mJ·cm−3, were obtained, competing with giant magnetostrictive materials like Terfenol-D or Galfenol.

An Investigation of the Energy Harvesting Capabilities of a Novel Three-Dimensional Super-Cell Phononic Crystal with a Local Resonance Structure.

Using the piezoelectric (PZT) effect, energy-harvesting has become possible for phononic crystal (PnC). Low-frequency vibration energy harvesting is more of a challenge, which can be solved by local resonance phononic crystals (LRPnCs). A novel three-dimensional (3D) energy harvesting LRPnC is proposed and further analyzed using the finite element method (FEM) software COMSOL. The 3D LRPnC with spiral unit-cell structures is constructed with a low initial frequency and wide band gaps (BGs). According to the large vibration deformation of the elastic beam near the scatterer, a PZT sheet is mounted in the surface of that beam, to harvest the energy of elastic waves using the PZT effect. To further improve the energy-harvesting performance, a 5 × 5 super-cell is numerically constructed. Numerical simulations show that the present 3D super-cell PnC structure can make full use of the advantages of the large vibration deformation and the PZT effect, i.e., the BGs with a frequency range from 28.47 Hz to 194.21 Hz with a bandwidth of 142.7 Hz, and the maximum voltage output is about 29.3 V under effective sound pressure with a peak power of 11.5 µW. The present super-cell phononic crystal structure provides better support for low-frequency vibration energy harvesting, when designing PnCs, than that of the traditional Prague type.

Subharmonic resonance and fixed-range asymptotic stability of the fractional-order SD oscillator

The smooth and discontinuous (SD) oscillator is a typical system with strong nonlinear characteristics, and it is widely used in low-frequency vibration isolation and energy harvesting. A fractional damping model denoted by the Caputo model is introduced into the SD oscillator to adjust the property of the secondary resonance and evaluate the stability of the system. The influence of the fractional damping model on the one-third subharmonic resonance and the fixed-range asymptotic stability is studied. Residue theory and the Laplace transform are used to solve the fractional damping model. The amplitude–frequency response function and the existence conditions are derived by means of the averaging method. Lyapunov theory is used to determine the stable criteria of steady-state solutions. The cell-mapping method is ameliorated and used to calculate the fixed-range asymptotic stability of the one-third subharmonic resonance. The main results are as follows: a gap in the excitation amplitude occurs in the region of the existence condition of the one-third subharmonic resonance when the smooth parameter is smaller than 1. The generation of one-third subharmonic resonance is totally avoided for all frequencies when the excitation amplitudes are within the gap. The width of the gap, as well as the amplitude of the one-third subharmonic resonance, is affected by the parameters of the fractional damping term. The fixed-range asymptotic stability of the one-third subharmonic resonance is weak when the fractional damping parameters are large, which indicates a low resistance of the one-third subharmonic resonance to the external disturbance. The tuning effects of the fractional damping model on the one-third subharmonic resonance and fixed-range asymptotic stability are beneficial for the applications of SD oscillators.

Analytical and Experimental Investigations on Low-Frequency Simultaneous Vibration Isolation and Energy Harvesting Using Magnetic Rings

Analytical and Experimental Investigations on Low-Frequency Simultaneous Vibration Isolation and Energy Harvesting Using Magnetic Rings

A high-output performance disc-shaped liquid-solid triboelectric nanogenerator for harvesting omnidirectional ultra-low-frequency natural vibration energy

Low-frequency vibrations, such as ocean waves, are widely distributed in nature and serve as a promising renewable energy source. Triboelectric nanogenerators (TENGs) have been shown to be an effective method for harvesting low-frequency vibration energy. However, most TENGs can only effectively harvest vibration energy in a single direction and a specific vibration mode. To solve the problem, we developed a disc-shaped liquid-solid triboelectric nano-generator (DLS-TENG) that can harvest vibration energy omnidirectionally. Benefiting from the high flexibility of the fluid and the ultra-high surface utilization of the disc structure, the DLS-TENG has the highest volumetric charge density and load driving capability in harvesting omnidirectional vibrational energy. Driven by seesaw vibrations with a frequency of 0.5 Hz and an amplitude of 30°, one DLS-TENG successfully lit up 544 LEDs simultaneously, with a transferred charge of 1263 nC. Considering the random, irregular, and variable characteristics of most ambient vibrations, our omnidirectional TENG is more practical. The proposed DLS-TENG can achieve long-term and efficient natural vibration energy harvesting to power an increasing number of microsensors widely distributed in the field.

Converting energy from overhead transmission line vibrations using a low-frequency and low-amplitude harvester in a smart grid

Introduction: Overhead transmission line vibration is detrimental to the normal operation of the power grid. It is necessary to remotely monitor overhead transmission lines with sensors in normal operation, and sensors require a constant source of energy. Harvesting energy from transmission line vibrations is an excellent solution to power these sensors.Methods: A low-frequency and low-amplitude vibration energy harvester is proposed, analyzed, produced and experimented in this study. A main constituent of the energy harvester is an outer support, an inner support, four one-way bearings, a bevel gear system and a DC generator. The harvester converts the linear reciprocating motion of the line into reciprocating swing at first and then converts it into fixed-direction rotation. Theoretical analyses are conducted to determine the harvester performance factors. Finally, the harvester is fabricated and tested.Results: The test results are in good accordance with the simulation results. At the vibrating speed as 0.48 m/s, the maximum output power and output voltage are 4.2 W and 24.7 V, respectively. The weather sensor and video recorder installed on the transmission line are powered by the harvester.Discussion: The energy harvester also effectively suppresses the vibration of transmission lines and has great potential in the constructions of smart grids. The harvester provides a feasible solution for harvesting line vibration energy and suppressing line breeze vibration simultaneously.