Broadband Vibration Energy Harvesting Research Articles

All‐Polarized Elastic Wave Attenuation and Harvesting via Chiral Mechanical Metamaterials

AbstractManipulating elastic waves of all polarizations is highly challenging due to the complex behavior of elastic waves. To achieve simultaneous broadband vibration attenuation and energy harvesting across all polarizations of elastic waves at low‐frequency ranges, a chiral mechanical metamaterial‐based energy harvester is proposed in this study. The systematic development of a complete bandgap and defect structure is achieved through theoretical eigenfrequency analysis and numerical simulations. The defect structure is incorporated to induce defect modes for all wave polarizations within the complete bandgap region, ensuring their compatibility with the overall shape of the structure. The proposed chiral mechanical metamaterial with defect (CMMD) demonstrated significant performance improvements, achieving electrical output power enhancements that are 20.5 times for flexural waves and 511.4 times for longitudinal‐torsional waves compared to the defectless chiral mechanical metamaterial. This study accentuates the thoughtful design and multifaceted utility of chiral mechanical metamaterials, paving the way for their application not only in energy harvesting but also in wave attenuation for various polarizations.

Kresling origami-inspired electromagnetic energy harvester with reversible nonlinearity

This paper presents an electromagnetic energy harvester based on a unique nonlinear Kresling origami-inspired structure. By introducing the equilibrium shift phenomenon, reversible nonlinearity (i.e. mixed softening-hardening behavior) empowers the proposed harvester to work in a broad frequency band, confirmed by both simulation using a dynamic model and experimentation. The prototyped device can produce the open-circuit root mean square (RMS) voltage from 0.09 V to 0.20 V in the reversibly nonlinear response region in (6.19 Hz, 9.63 Hz) and a maximum output power of 0.4956 mW at an optimum load of 18.1 Ω under the excitation of 1.1 g. Moreover, detailed research further reveals that the design parameters of Kresling origami-inspired structure and electrical and mechanical loads influence reversible nonlinearity. Increasing the tip mass and γ 0 in the M2 region of the design map strengthens the softening behavior, and enlarging the electrical load enhances the hardening behavior. The findings from this work deepen the understanding of the nonlinear behavior of Kresling origami, unveils the great potential of origami structure in energy harvesting and offers a new method to realize broadband vibration energy harvesters.

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.

Reversible nonlinear energy harvester tuned by titling angle or clamping distance

This paper proposes a reversible nonlinear energy harvester to realize broadband vibration energy harvesting. Especially, the softening and hardening nonlinear responses of an M-shaped piezoelectric beam could occur by tuning the clamping distance or titling angle, which is unlike previous efforts to institute nonlinearity. The proposed M-shaped beam consists of a pre-bent steel beam, a piezoelectric patch, and a proof mass without magnetic components. According to the numerical and experimental results, the proposed harvester could achieve a broader operation bandwidth than its linear counterpart. Under the low forward sweep excitation level (3 m/s2), the proposed reversible nonlinear energy harvester can cover the wide low-frequency range of 13.4–27.6 Hz (or 18.1–28.8 Hz) by changing the clamping distance (or the tilting angle). Exploiting this tunable nonlinear phenomenon makes it more suitable to harvest energy from broadband vibration efficiently.

A novel design of an array of pendulum-based electromagnetic broadband vibration energy harvester

This work investigates a novel design of an electromagnetic vibration energy harvester array based on pendulum structures under harmonic base excitation. The design includes combined magnetic-solenoid pendulum harvesters with different mechanical coupling configurations. A comparison is made with standalone magnetic and solenoid pendulum based harvester arrays under similar excitation conditions. Additionally, the positions of harvesters are shuffled and analyzed. The effects on harvested power, power density and frequency bandwidth are evaluated by considering dimensionless coupling ratios, damping ratios, mass ratios and length ratios as parameters. Further, the efficiency of the harvester against these parameters has also been reported. In addition, experimental validation of the numerical formulation is also conducted. The study shows that the proposed magnetic-solenoid harvester array can harvest sustained energy in a wider bandwidth compared to standalone magnetic and solenoid pendulum harvester arrays.

Mechanical energy conversion to electricity through periodically stress-induced martensitic transformation in Co-Ni-Ga

We anticipate and demonstrate experimentally the mechanical-to-electrical energy conversion through the variation of magnetization resulting from a periodical stress-induced martensitic transformation in the single crystalline Co-Ni-Ga ferromagnetic shape memory alloy. Dynamic loading in a stress-induced austenite-martensite two-phase state was performed with the peak-to-peak strain amplitude from 0.002 to 0.024 in a frequency range of 25 - 150 Hz. A reproducible superelastic behavior occurred at all frequencies. Alongside this remarkable result, we found that the electrical power output depends quadratically on the peak-to-peak strain. This study suggests a new route for the development of broad-band vibration energy harvesting devices.

A bio-inspired system for simultaneous vibration isolation and energy harvesting in post-capture spacecraft

Vibrations and drifting motions of a post-capture spacecraft may lead to its instability and safety risk, which therefore need to be absorbed or isolated. However, it is expected that the vibrational energy is not wasted but harvested to power the wireless sensors. Motivated by this concept and inspired by the movement of a bird, a quadrilateral shape isolation system with an energy harvester is proposed for the simultaneous broadband vibration isolation and energy harvesting of the post-capture spacecraft. The governing equations of the proposed system are derived based on Hamilton’s principle. The corresponding dimensionless approximate analytical model is deduced based on the harmonic balance method and validated through the comparison with the numerical Runge–Kutta method. Simulation results demonstrate that compared with its counterpart without the energy harvester, the proposed system can further improve the broadband vibration isolation performance, and achieve the energy harvesting function simultaneously. The operation principle is the energy localization effect, which is demonstrated through the investigation on system dynamics. The guideline for improving the dual performances is proposed according to the parametric studies on the mass ratios, the equivalent stiffness and damping induced by the quadrilateral shape structures, and the mechanical and electrical parameters of the energy harvester.

A 3D multi-directional and multimodal broadband vibration energy harvester using an L-shaped bending beam

A three-dimensional (3D), multi-directional and multimodal broadband vibration energy harvester using L-shaped curved beams is proposed in this paper. The harvester is composed of an L-shaped cylindrical bending beam and a piezoelectric beam. The free ends of the L-shaped bending beam and the piezoelectric beam are respectively fixed with a magnet. These two beams are coupled by nonlinear magnetic force introduced by the two magnets. The results show that the prototype can collect 3D multi-directional broadband vibration energies and has three natural frequencies in 3D directions. Under 5 m/s2 acceleration, the prototype obtains 42.1V, 45.0V and 66.9V peak-peak voltages in the x-direction, y-direction and z-direction respectively, and the widest 3 DB bandwidths in this three directions reach up to 6.4Hz, 6.3Hz and 4.2Hz, respectively.

Broadband omnidirectional piezoelectric–electromagnetic hybrid energy harvester for self-charged environmental and biometric sensing from human motion

Vibration induced by human motions features a wide frequency spectrum and spatiotemporal-variable directions. Yet, it is challenging to concurrently expand frequency bandwidth and achieve multidirectional capability for effectively human-induced biomechanical energy harvesting and biometrics sensing. In this paper, we report a piezoelectric–electromagnetic hybrid energy harvester with coupled vibrational stabilization and induced frequency-up rotational mechanisms for omnidirectional and broadband vibration energy harvesting. Experimental studies demonstrate the proposed hybrid energy harvester operates effectively over a wide excitation frequency range from 6.0 to 16.0 Hz with omnidirectional responses. The piezoelectric conversion unit can provide a maximum output power of 0.9 mW and the electromagnetic conversion unit’s maximum output power is 22.7 mW. The hybrid energy harvester satisfies the power requirements of different types of portable electronics and realizes various self-charged sensing electronics that are stimulated by human movement. Various types of human motion signals are detected by piezoelectric and electromagnetic units via machine learning techniques to realize self-powered motion monitoring. Compared with a single type of signal, the identification accuracy of the hybrid device is improved from 85.6% to 100%. The proposed energy harvester for self-powered sensing paves the way to green intelligent life such as health management, environmental monitoring and human-machine interaction.

Modeling and analysis of magnetically coupled piezoelectric dual beam with an annular potential energy function for broadband vibration energy harvesting

Modeling and analysis of magnetically coupled piezoelectric dual beam with an annular potential energy function for broadband vibration energy harvesting

Simultaneous broadband vibration isolation and energy harvesting at low frequencies with quasi-zero stiffness and nonlinear monostability

Vibration, as one of the most ubiquitous phenomena, would be a sustainable energy harvesting source to power wireless sensor nodes. However, vibration may be undesirable with detrimental effects such as damage to buildings, discomfort to passengers, etc. So far, the simultaneous broadband energy harvesting and vibration isolation at low frequencies between 0 and 15 Hz is still an open issue. Motivated by this, we propose a novel device with a quasi-zero-stiffness (QZS) support through cam–roller–spring mechanism (CRSM) and multiple nonlinear monostable piezoelectric energy harvesters. A semi-analytical electromechanical model considering AC/DC circuits is developed and validated. Simulation results show that when the high-energy branches of the proposed device with six nonlinear monostable harvesters are triggered, the peak power and energy harvesting frequency bandwidths are respectively increased by up to 69.29% and 1.22 times compared with those of its counterpart with linear harvesters. Furthermore, these are achieved at frequencies lower than 15 Hz without the sacrifice of low force transmissibility and isolation frequencies. Parametric studies indicate that except for the harvester damping, no matter how other parameters change, the superiority of the proposed device exists compared with its linear counterpart. It can be potentially used in building a smart floor tile with dual functions of energy harvesting to power wireless sensor nodes for footfall tracking or light-emitting diodes, and vibration isolation to enhance pedestrian comfort and safety.

Research on Vibration Energy Harvester Based on Two-Dimensional Acoustic Black Hole

The wave energy focus effect of an acoustic black hole (ABH) is used for broadband vibration energy harvesting and boosts the harvested power. A vibration energy harvester based on two-dimensional ABH is proposed in this study, which consists of a rectangle plate with 2-D ABH and PZT film attached. The structure of ABH was designed and analyzed based on numerical simulation. The optimal parameters of the ABH were obtained, such as the power index, truncation thickness, cross-sectional length, and round table diameter, which were 3, 0.4 mm, 40 mm, and 24 mm, respectively. The quadratic velocity of the plate surface with ABH is up to 22.33 times that of a flat plate, and PZT film adheres to the corresponding positions of the ABH structure and plate structure, respectively. In the same condition, the average output power of a PZT with an ABH structure is higher than that of a flat plate under the same excitation-vibration condition.

A multimodal E-shaped piezoelectric energy harvester with a built-in bistability and internal resonance

The abundant and renewable vibration energy has been regarded as an alternative power source for the massive sensors of the Internet of Things, but the broadband and efficient vibration energy harvesting is still an open issue. In this paper, a broadband E-shaped bistable piezoelectric energy harvester (EBPEH) is developed by taking advantages of nonlinear and multimodal techniques. It is consisted of a steel U-shaped host beam (UHB) and a steel parasitic piezoelectric cantilever beam (PPCB). The nonlinear interaction between a tip magnet of the PPCB with the UHB cause a built-in bistability of the harvester, eliminating the need of any external magnet and leading to a compact structure. By appropriately designing multimodal frequencies of two beams, a 1:2 internal resonance phenomenon in the first response frequency band occurs, and an overlapping of them above a low excitation amplitude threshold cause a triple bandwidth enhancement from 6 Hz to 18.5 Hz. Attributed to the nonlinear hardening phenomenon, the peak voltage and the RMS peak power can reach 56.1 V and 786.8 μW under the 0.5 g up sweep excitation, respectively. It is proved that the proposed EBPEH has the ability to harvest wideband and low frequency vibration energy.

Design and Development of a Broadband Vibration Energy Harvester Suitable for Tractor Exhaust Cylinder Vibration

A large amount of vibration energy exists in the working environment of tractors. Therefore, the use of vibration energy harvesting technology to convert the vibration energy into electrical energy is a feasible way to supply power to low-power sensor equipment in agricultural machinery. Aiming at the problem in which the internal sensors of traditional tractors require built-in batteries or overlapping cables, this work proposes a broadband piezoelectric vibration energy harvester that could harvest the vibration energy from the tractor exhaust cylinder when the tractor is working. The vibration energy can be converted into electrical energy to power the air pressure sensor device. This experimental investigation shows that the energy harvester is composed of a folded piezoelectric energy harvester and a multi-source input synchronous electronic charge extraction circuit.The circuit has a high power density of 12,398 μW/(mm3·g2). Hence, it can convert vibration energy into a wide frequency range between 90-140 Hz and cause the air pressure sensor to operate.

Variable-potential bistable nonlinear energy sink for enhanced vibration suppression and energy harvesting

A variable-potential bistable nonlinear energy sink coupled electromagnetic harvesters (VBNES-EH) is proposed, that can simultaneously achieve high efficiency, broadband vibration suppression and energy harvesting under ultra-low and ultra-wide input energy level excitation. The performance is enhanced by introducing two horizontal energy harvesters (HEHs) to dynamically reduce the potential barrier height of the bistable nonlinear energy sink (BNES) or called bistable energy harvester (BEH) to form lower excitation thresholds of the chaotic and strong modulated responses. Firstly, the dimensionless mathematical model of the VBNES-EH is proposed and verified by the experiment. The experimental results are qualitatively consistent with the simulation results. The transient dynamics and the corresponding energy dissipation rates of five target energy transfer (TET) mechanisms for the weakly damped system are summarized numerically. The variable-potential energy effect and its benefits for the dual functions of vibration suppression and energy harvesting are analyzed. Afterward, the stiffness of the VBNES-EH and the fixed-potential BNES-EH (FBNES-EH) are optimized, and their energy dissipation rates under impact excitation are compared. The results indicate that the former has better performance under low- and intermediate-level impact excitations. Furthermore, the influence of system parameters on the energy harvesting rate is discussed to guide the optimal design of the performance. Finally, the dynamical evolution of the VBNES-EH and the parameter effects on the dual performance of the system under harmonic sweep excitation are investigated. Numerical results demonstrate that the VBNES-EH can achieve high performance under the different amplitudes of the harmonic excitation through stiffness optimization.

Comparison of L-Shaped and U-Shaped Beams in Bidirectional Piezoelectric Vibration Energy Harvesting.

The traditional single degree of freedom linear piezoelectric vibration energy harvester (PVEH), such as the cantilever type, mainly works and resonates in a single direction and at a single frequency. To adapt broadband and bidirectional ambient vibration, this paper designs and compares two PVEHs of L-shaped beam and U-shaped beam through COMSOL simulation and prototype test. FEA modeling is introduced for accurate structure design with modal analysis, voltage frequency response analysis, and proof mass analysis with multiphysics electromechanical coupling simulation. Two PVEH prototypes with different gravity angles and clamping angles are tested at 0.1 g acceleration to find the optimal angle for maximum output power. The best clamping angle of L-PVEH is 135° with RMS power of 0.3 mW at 7.9 Hz, and that of U-PVEH is 45° with RMS power of 0.4 mW at 5.0 Hz. The proposed U-PVEH shows more advantages in low broadband and bidirectional vibration energy harvesting.

Experimental study of a two-degree-of-freedom piezoelectric cantilever with a stopper for broadband vibration energy harvesting

This paper presents a two-degree-of-freedom (2-DOF) piezoelectric energy harvesting (PEH) system with a stopper for wideband operation. The proposed system consists of a folded piezoelectric cantilever with a stopper integrated. Two cases are considered where the stopper is placed at the free end of the outer beam and inner beam, respectively. It is shown experimentally that with the proper parametric combination we can move the anti-resonance point outside the two resonant peaks and widen the frequency responses of both the peaks. Large amplitude voltage output over 11 Hz can be obtained when we focused on the dynamics of the inner beam. In addition, it is demonstrated that arranging the stopper at the free end of the inner beam yields better performance than that with the stopper placed at the outer beam. Detailed parametric studies are performed to investigate the influences of the stopper distance, amplitude of base movement, and frequency sweep directions on the voltage output. A maximum power output of 713μW is obtained.

Wideband energy harvesting using nonlinear energy sink with bio-inspired hexagonal skeleton structure

Inspired by human fitness push-ups, a bio-inspired hexagonal skeleton structure is proposed to design wideband energy harvesters using nonlinear energy sink. The hexagonal skeleton structure consists of two symmetrical bionic arms as skeleton, a horizontal spring as muscle and two platforms (upper and lower) as the back of human body and the ground. The lower platform is supported by linear springs, and the upper platform is supported by the bio-inspired hexagonal skeleton structure as nonlinear energy sink. Magnets are attached to the upper and lower platforms respectively. The piezoelectric beam is fixed on the upper platform. The dynamic equations of the wideband energy harvesting via bio-inspired nonlinear energy sink structure are established for theoretical analysis, which is verified by both simulations and experiments. The effects of nonlinearity, equivalent mass of the upper platform, parameter of BNES and acceleration level are discussed with the perspective of optimizing the magnitude and bandwidth of the output voltage and power. The harvester can cover a broad low-frequency range of 5–15 Hz, and convert the hybrid vibration into electricity effectively. The maximum output power of the electromagnetic units can reach 0.18 mW and 0.63 mW respectively, and the maximum output power of the piezoelectric unit can reach 0.1 mW as a supplement to the power at the low excitation level of 0.08 g (g= 9.8 m/s2). This means that the wideband energy harvester using nonlinear energy sink with bio-inspired hexagonal skeleton structure should be a viable solution for the hybrid, low-frequency, and broadband vibration energy harvesting.

Broadband vibration energy powered autonomous wireless frequency monitoring system based on triboelectric nanogenerators

Vibration frequency monitoring is an important means of safety inspection and fault detection for mechanical equipment, in which the vibration sensors are mainly powered by batteries or cables. Herein, we report a broadband vibration energy powered autonomous wireless frequency monitoring system (AWFMS) based on two triboelectric nanogenerators (TENGs), in which one is used for broadband vibration energy harvesting (P-TENG) and the other is used for active vibration frequency sensing (S-TENG). In a broad range of 6–20 Hz, the output voltage of P-TENG can be converted to a stable direct current voltage of 2.5 V by power management module and drive the microcontroller unit (MCU). While the output signal of S-TENG is acquired and processed by the MCU for the frequency calculation and wireless data transmission. By integrating both characteristics of TENG as a power source and a sensor, the AWFMS has provided an effective solution for self-powered and autonomous vibration monitoring. Moreover, the AWFMS is used as a sensor network node and the transmitted data can be relayed to cloud platform by Narrow Band Internet of Things technology. This work has shown extensive applications and promising prospects of TENG in Internet of Things, big data, and smart factory

Broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums

A broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums is proposed in this paper. The harvester is mainly composed of a magnetoelectric transducer and a rotary pendulum fixed with four permanent magnets. In order to improve the working bandwidth of the harvester, two pairs of permanent magnets are added in the middle of the rotary pendulum by using magnetic nonlinearity. The mechanical–magnetic–electrical analytical model of the harvester is established, and the theoretical value obtained by the model is basically consistent with the experimental value. The results show that the harvester has a strong nonlinearity through the magnetic force. When the acceleration is 0.4 g, some typical testing results are as follows: the resonant frequency is 19 Hz, maximum peak–peak voltage is 94.1 V, half power bandwidth is 15.8 Hz, center frequency is 26.9 Hz, and the ratio of half power bandwidth to the center frequency is 58.73.