Low-frequency Vibration Energy Research Articles

Dynamic modeling and experimental validation of a low frequency piezoelectric vibration energy harvester via secondary excitation of pressured fluid

A low frequency piezoelectric energy harvester using secondary excitation of pressured fluid is proposed in this paper to scavenge low frequency vibration energy in ambient environments. This harvester was characterized by an indirect vibration-to-electric energy converter via transferring the pressure energy of pressured liquid medium. A series of simulations and experiments were conducted to prove the good performance and the feasibility of this novel structure in low-frequency high-intensity vibration. The results showed that the diameter of damping orifice, initial system backpressure and proof mass brought strong influences on the resonance frequency and output voltage. Meanwhile, according to experiments, it was found that the resonance frequency was decreased with the decreasing liquid backpressure. In this case, lowest resonance frequency of 19 Hz was achieved under the condition of 10-kg proof mass and 0.2-MPa liquid backpressure. Also, there were the optimal proof mass and backpressure to maximize the generated voltage, respectively. Moreover, in the impedance matching experiments, the maximum output power reached 1.35mW at the matching load resistance of 18kΩ.

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.

Dual-function quasi-zero-stiffness dynamic vibration absorber: Low-frequency vibration mitigation and energy harvesting

The dynamic vibration absorber (DVA) can effectively suppress undesirable vibration of a host structure, and the energy harvester is also proven to be a feasible way to collect vibration energy from the host structure. However, it is almost impossible to achieve high-efficiency vibration attenuation and energy harvesting at ultra-low frequency by conventional methods. In this paper, a dual-function quasi-zero-stiffness (QZS) energy harvesting dynamic vibration absorber (EHDVA) is proposed to mitigate vibration and harvest energy simultaneously. The proposed device mainly composed of a QZS absorber and an electromagnetic transducer. The quasi-zero stiffness is realized using a vertical spring connecting with two oblique springs in parallel. The electromagnetic transducer consists of permanent magnets and coils, and any relative motion between the permanent magnets and coils brings flux linkage variation and generate induced voltage. Firstly, the theoretical model of the QZS EHDVA is established and the statics analysis of QZS absorber is carried out. Then, the Harmonic Balance Method (HBM) along with numerical path continuation is applied to solve the electromechanical coupled equations of the QZS EHDVA. Moreover, both numerical and analytical methods are used to evaluate the influence of mechanical and electrical parameters on performances of vibration absorption and energy harvesting. Finally, the H∞ optimization on system parameters of the QZS EHDVA are conducted with the aid of perturbation method. It indicates that the optimized QZS EHDVA can considerably reduce resonance peaks of the host oscillator at ultra-low frequency and effectively enhance energy harvesting at the same time.

A wearable collaborative energy harvester combination of frequency-up conversion vibration, ambient light and thermal energy

In this study, a wearable multi-source collaborative energy harvester (MC-EH) is proposed to overcome the problem that a single-source EH is unstable from time to time. A customized ring monocrystalline silicon photovoltaic (PV) cell on the surface of energy harvester (EH) is used to harvest ambient light energy. The thermoelectric generator (TEG) converts the thermal energy of the temperature difference into electrical energy. A Macro-Fiber Composite (MFC) constitutes piezoelectric frequency up-conversion rotating structure, which harvest the low frequency vibration energy. The advantages of designed MC-EH are that energy of human body and environment can be fully harvested. Due to the difficulty in extracting small voltage generated by TEG independently, MC-EH was improved that it can extract thermal energy in the process of vibration energy extraction efficiently by the interface circuit. Results showed that maximum output power of harvester was about 4.48 mW, power density was 1.5 × 10−4 W/cm3. MC-EH can work efficiently in different human movement states and environments conditions. Therefore, MC-EH may provide electric energy for wearable device. Three energy harvesting systems are integrated into one compact structure by MC-EH, forming the advantages and originality of MC-EH that brought a case study of EH.

Impact-driven frequency-up converter based on high flexibility quasi-concertina spring for vibration energy harvesting

In this paper, an impact-driven frequency-up converter for low-frequency vibration energy harvesting is proposed and investigated. Low-frequency vibration presents a significant challenge in vibration energy harvesting, and frequency-up conversion is one of several techniques used to tackle this concern. The proposed design is based on a high-flexibility Quasi-Concertina (QC)-based structure with a resonant frequency of ∼25 Hz, along with high-frequency piezoelectric cantilevers of a resonant frequency of ∼250 Hz. The mathematical model describing the operating sequence of the frequency-up conversion approach was initially developed. Experimental studies of the manufactured device were also conducted to validate the concept and to evaluate the performance and efficiency of the system under different frequencies, accelerations, and gaps between the QC structure and the piezoelectric cantilevers. The system achieved a peak voltage of 10 V (RMS voltage of 3.40 V) when subjected to vibrations of 2 g@25.5 Hz for an air gap of 2 mm. We also explored the possibility of using four piezoelectric cantilevers. Theoretically, the peak voltage dropped to 16 V; however, the RMS voltage increased to 8.44 V due to the slow damping of the generated output signal. The bandwidth was equal to 24–28 Hz for an acceleration of 1.8 g and 25–27.5 Hz for 1.4 g.

A self-powered bridge health monitoring system driven by elastic origami triboelectric nanogenerator

Bridge health monitoring system can play a role in bridge safety early warning, fatigue diagnosis, and life prediction. However, traditional bridge health monitoring system relies on manpower or battery power supply, which challenges the real-time effectiveness of health monitoring sensors. Herein, we proposed a self-powered bridge health monitoring system based on the elastic origami structure triboelectric nanogenerator (EO-TENG) array. In detail, the self-powered bridge health monitoring system contains the self-powered bridge health data acquisition/processing modular and the NB-IoTs communication modular. The EO-TENG follows an elastic origami structure design and can convert the low-frequency impact vibration energy into multiple frequency current output. With the integrated PMC, the EO-TENG array can provide the stable direct current (DC) voltage on the external load. Furthermore, the EO-TENG array with power management circuit (PMC) and energy storage device can drive the data processing modular to obtain and process vibration signals from piezoelectric patch. The NB-IoTs communication modular can send the vibration information to the terminal. Our design can provide a new system framework for TENG device in the bridge monitoring field. This design will promote the application of TENGs in the bridge monitoring field.

Bandwidth enhancement of a gimbaled-pendulum vibration energy harvester using spatial multi-stable mechanism

Vibration energy harvesting based on pendulums is a promising approach for low-frequency excitation and large-scale application. Conventional design is to match the natural frequency of the pendulum energy harvester to the excitation frequency, which results in a narrow bandwidth. This work develops a gimbaled-pendulum energy harvester with spatial multi-stability by using a magnetic mechanism. The structure, modeling, design consideration, and dynamic simulation of the energy harvester are presented in detail with the aid of numerical analysis. Comparative experiments such as motion patterns, electrical outputs with variable excitations, load effect, and bidirectional excitation are implemented based on a fabricated prototype to evaluate the proposed design. It is shown that the energy harvester is prone to enter into high-energy orbits even at low excitation frequency and amplitude due to the effect of multi-well potential distribution. In general, the bandwidth of the energy harvester is significantly enhanced through its spatial multi-stability. This work can provide a candidate for low-frequency vibration energy harvesting with wide spectrum excitation.

Design and Characteristic Analysis of Magnetostrictive Vibration Harvester with Double-Stage Rhombus Amplification Mechanism

Vibration energy harvesting is a new alternative to lithium battery power for low-power devices, attempting to recover wasted or lost vibration energy to generate electricity. Magnetostrictive-based energy harvesting exploits the coupling properties of the Villari and Faraday electromagnetic induction effects to achieve mechanical–magnetic–electric energy conversion. In order to better apply to the actual vibration environment, such as buses, and improve the ability to capture low-frequency vibration energy, a double-stage rhombus vibration energy harvesting device, based on Terfenol-D rods, was developed. By establishing an analytical model of the force amplification ratio of the harvesting device, the design is optimized using the Single-Objective Genetic Algorithm, and the safety and pre-magnetization layout methods are analyzed by Finite Element Analysis. The output characteristics of the prototype, including the output voltage frequency response under low-frequency regular excitation and random excitation, the effect of external resistance, and the vibration energy capture performance under random excitation, are investigated in detail through experiments. The results of the experiments showed that the peak output power of the fabricated prototype was 1.056 mW at 30 Hz operating frequency, the energy harvesting capability reached 41.4 μW/N, and the peak open circuit voltage and output power were 2.92 V and 266 mW, respectively, under random excitation. Practical application test results showed that the peak voltage generated was 1.06–1.51 V when the excitation level was 2.2–4.9 m/s2. The comparative study indicates that the output performance of the proposed double-stage rhombus magnetostrictive vibration energy harvesting system is a great improvement over the proposals of existing literature.

Auxetic hexachiral cantilever beams for piezoelectric vibration energy harvesting

This work presents an auxetic hexachiral cantilever substrate for low-frequency vibration energy harvesting applications. Auxetics are materials with negative Poisson’s ratio that develop stresses of the same nature under mechanical loading, which can be advantageously used in designing energy harvesters with enhanced power output. The proposed harvester is fabricated by attaching a piezo patch on a 3D printed polylactic acid hexachiral substrate to convert the mechanical response to electrical output. Experiments are conducted to characterize the vibration and electrical properties of the harvester. A 3D finite element (FE) model is developed and validated with experimental voltage obtained for different electrical resistance. As the first mode generates maximum power, an equivalent single degree of freedom semi-analytical model is formulated and validated with experiments and FE results. The proposed harvester has a natural frequency of 23 Hz with a voltage output of 9.1 V at 250 kΩ. The developed models are used to study the influence of hexachiral geometry, electrical and mechanical loading on the electro-mechanical response. The harvester voltage is influenced by the ligament thickness and is found to increase linearly with an increase in mechanical loading. Further, the enhancement in performance by the addition of hexachiral sub patch to a plain beam is investigated, followed by a comparison with harvesters having plain, hexagonal and re-entrant geometries. The results show that the hexachiral harvester has the lowest first mode frequency with a power output about 20 and 3 times the plain and re-entrant harvesters, respectively. Finally, random vibration analysis of the hexachiral harvester is carried out to evaluate its performance under ambient loading, and the results show that the semi-analytical model is a computationally efficient alternative to study the first mode behavior. The findings of the study demonstrate the potential of the proposed hexachiral harvester for low-frequency applications.

Dipteran flight-inspired bistable triboelectric nanogenerator for harvesting low frequency vibration

Triboelectric nanogenerator (TENG) is a new type of self-powered equipment which can collect vibration energy in the environment. However, using traditional linear float technology is difficult to achieve the low frequency vibration energy harvesting of broadband. In order to solve the problem of the bandwidth limitation the output of TENG, dipteran flight-inspired bistable triboelectric nanogenerator (DFIB-TENG) was proposed in this paper, which was inspired by the flying mechanism of the double wing. The effects of excitation frequency, amplitude and the link length on the energy harvesting of the DFIB-TENG are studied. The results show that the DFIB-TENG has high output in the wide range of 3–7 Hz. The DFIB-TENG has the maximum energy output in the excitation frequency of 6 Hz, the excitation amplitude is 40 mm and the link length is 65.0 mm. The short circuit current of the DFIB-TENG is 12.17 μA, and the output voltage is 1108 V, the output power is 1.25 mW. The DFIB-TENG can drive 50 led lights or feed the electronic watch when working. The dynamic model of the DFIB-TENG was established by the Euler-Lagrange equation, and the dynamic response was analyzed by numerical analysis. The numerical simulation results are consistent with the experimental results, and the correctness of the completion results is verified. The DFIB-TENG can be used to harvest low frequency bridge vibration energy, providing electricity for its health monitoring and sensing network.

Global dynamics for a class of tristable system with negative stiffness

Tristable system with negative stiffness has attracted extensive attention in the low frequency vibration isolation and vibration energy harvester. As a low frequency vibration isolator, it can achieve high static stiffness and low dynamic stiffness. As a vibration energy harvester, it had a wider bandwidth for resonance than the bistable one. The introduction of negative stiffness may induce subharmonic resonance and chaos in the tristable system. Chaos usually brings disorder to mechanical vibration system. Subharmonic resonance plays the negative effect on low frequency vibration isolation because they will transfer the high frequency energy of the system to the low frequency, but it is beneficial to broaden the working frequency band of vibration energy harvester. In this paper, the subharmonic bifurcation and chaos of a class of tristable system with negative stiffness are studied. The piecewise linearized systems are established to approximate the system with tristable potential. In order to conduct Melnikov analysis, the homoclinic-heteroclinic orbits and periodic orbits for the unperturbed piecewise linearized system are obtained respectively. The subharmonic Melnikov method for nonsmooth systems with four switched manifolds is developed. The thresholds for homoclinic-heteroclinic chaos and subharmonic resonance are derived by using non-smooth Melnikov method. It provides a theoretical support not only for design of the vibration energy harvester to obtain wider working frequency band, but also for design of the vibration isolation system to avoid high frequency energy transfer to low frequency. Moreover, the phenomena for infinite subharmonic bifurcations to chaos from odd order subharmonic orbit and the coexistence for chaotic and subharmonic attractors are revealed. The subharmonic Melnikov method with four switching manifolds developed in this paper lays a foundation for the subharmonic resonance analysis of other nonsmooth tristable systems.

Vibro-impact energy harvester for low frequency vibration enhanced by acoustic black hole

In this Letter, we propose an enhanced vibro-impact energy harvester using acoustic black holes (ABHs) for scavenging low-frequency vibration energy. The energy harvester involves two beams: a relatively rigid piezoelectric generating beam with ABH profile and a flexible driving beam with a tip mass mounted at the end. The tip mass and the generating beam collide repeatedly under low-frequency excitations. Experimental studies are conducted to investigate the output performance of the energy harvester by comparing the output power and voltage of generating beams with different tailored ends. Finite element analysis is also carried out to evaluate the influence of electrode number of the piezoelectric sheet attached to the ABH beam on the output performance of the energy harvester. It is shown that the impacts between the tip mass and generating beam are capable of transferring vibration energy from the low-frequency band to high-frequency band, where ABH gets a desirable energy focalization effect to improve the output performance of the energy harvester. The energy harvester achieves the best output performance when its electrode is divided into two parts with the excellent power of 0.7 mW at the low frequency range from 5 to 13 Hz.

A Cantilever Beam-Based Triboelectric Nanogenerator as a Drill Pipe Transverse Vibration Energy Harvester Powering Intelligent Exploitation System.

Measurement While Drilling (MWD) is the most commonly used real-time information acquisition technique in offshore intelligent drilling, its power supply has always been a concern. Triboelectric nanogenerators have been shown to harvest low-frequency vibrational energy in the environment and convert it into electricity to power small sensors and electrical devices. This work proposed a cantilever-beam-based triboelectric nanogenerator (CB-TENG) for transverse vibration energy harvesting of a drill pipe. The CB-TENG consists of two vibrators composed of spring steel with PTFE attached and Al electrodes. The structurally optimized CB-TENG can output a peak power of 2.56 mW under the vibration condition of f = 3.0 Hz and A = 50 mm, and the electrical output can be further enhanced with the increased vibration parameters. An array-type vibration energy harvester integrated with eight CB-TENGs is designed to fully adapt to the interior of the drill pipe and improve output performance. The device can realize omnidirectional vibration energy harvesting in the two-dimensional plane with good robustness. Under the typical vibration condition, the short-circuit current and the peak power can reach 49.85 μA and 30.95 mW, respectively. Finally, a series of demonstration experiments have been carried out, indicating the application prospects of the device.

Low-Frequency Broadband Piezoelectric Vibration Energy Harvester Based on Double L-shaped Beam Structures

Low-Frequency Broadband Piezoelectric Vibration Energy Harvester Based on Double L-shaped Beam Structures

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.

Evaluation of Vibration Effect Caused by Carbon Dioxide Phase-Transition Fracturing Based on the Hilbert–Huang Transform

To evaluate the vibration effect caused by carbon dioxide phase-transition fracturing, the Hilbert–Huang transform was used to study the change of vibration energy with distance in different frequency bands. The results are drawn as follows: (1) The peak particle velocity (PPV) decreases as a power function with an increase in distance and has fallen below 25 mm/s at 2.8 m. (2) The energy of vibration signals induced by carbon dioxide phase-transition fracturing is mainly distributed at the frequency band of 10–50 Hz. With the increase in distance, the energy distribution of vibration signals falls in four phases: Propagation to high frequency (0–13.9 m); a rapid high-frequency energy decrease (20–30 m); energy fluctuation (30–47.2 m) and a stable energy distribution (larger than 50 m). (3) The proportion of the low-frequency vibration energy (0–10 Hz) increases as a result of the increase in distance (less than 8.7 m), which should be paid more attention.

Inlay-inspired meta-piezoelectric plates for the low-frequency vibration energy harvesting

Inlay-inspired meta-piezoelectric plates for the low-frequency vibration energy harvesting

A 3D multidirectional piezoelectric energy harvester using rope-driven mechanism for low frequency and ultralow intensity vibration environment

Though numerous piezoelectric vibration energy harvesters (PVEHs) have been designed and investigated to provide power supply for wireless sensors or wearable devices, it remains a challenge for traditional PVEHs to work effectively in an environment of low frequency, low acceleration and multidirectional vibrations. This work presents a PVEH using a low-frequency energy-capturing resonant system formed by a rolling ball in a hemispherical shell and driven by a rope. Due to the symmetry of the sphere, the ball can be excited at multiple directions in 3D space, and the piezoelectric beam can be pulled by the ball through a rope in multiple directions. Thus, the efficient multidirectional energy harvesting under low frequency (<10 Hz) and ultralow intensity (<0.1 g) vibrations could be realized. A mass-spring-damper equivalent model was built to understand the operation mechanism of the proposed PVEH. The results show that the proposed PVEH has a potential to collect energy in any direction in 3D space, and could achieve a good angle bandwidth with 360° for ϕ and 240° for β under the excitation of a = 0.04 g, f = 6.8 Hz with the acceleration defined in the spherical coordinate system. The developed PVEH can generate 6.5 μW under a low-intensity excitation (0.03 g), and the normalized power density can reach 22.63 μW/(cm3 g 2Hz). Moreover, the minimum start-up acceleration analysis of the proposed PVEH indicates that the PVEH can capture multidirectional energy from vibrations as low as 0.01 g. In addition, both simulation and experimental study on rope redundancy and ball mass show that they can be used to adjust the device performance easily without structure re-fabrication. Overall, this study demonstrates a new mechanism that could effectively harvest low frequency, ultralow intensity and multidirectional vibration energy.

Bow-type bistable triboelectric nanogenerator for harvesting energy from low-frequency vibration

Triboelectric nanogenerators (TENGs) are emerging, leading-edge, and promising devices for converting ambient vibration energy into electrical energy and power for low-power sensors. However, it is difficult to harvest energy from low-frequency ambient vibrations using conventional TENGs. To solve this issue, in this study, we propose a bow-type TENG with a bistable stiffness feature, which enables the conversion of low-frequency vibration energy into electrical energy with high efficiency. The dynamic model of the bow-type TENG was established based on extended Hamilton’s principle and numerically solved to obtain the dynamic responses. Subsequently, a prototype of the bow-type TENG was fabricated and tested to verify the design concept. Moreover, the dependencies of the energy-harvesting performance on the structural parameters were experimentally investigated. The average power had a maximum value of 0.64 mW at 5 Hz in the case of optimal load resistance. The bow-type TENG could power a number of light-emitting diodes (LEDs) to display the word “HNU” under low-frequency excitation. Hence, the bow-type TENG can substantially extend the function of harvesting vibration energy from high to low frequencies.

Modeling and Optimization Analysis for Base-Excited Magnetostrictive Vibration Harvester

Due to the low vibration frequency and weak vibration energy in natural environment, the vibration energy harvester is faced with the problem of low power and low adaptability and becoming particularly difficult in actual conditions. It is necessary to improve the harvesting capacity and efficiency by optimizing the parameters of the harvester, making full use of the energy of low and unstable atmospheric vibrations. In this paper, a mathematical model is established for the cantilever magnetostrictive vibration harvester under the base excitation, including the mechanical deformation of the composite beam, and the electromagnetic results produced thereof. The mechanical-magneticelectric energy conversion relationship is duly taken into account. The additional weight, coil parameters, external resistance and other parameters of the harvester are optimized and analyzed through numerical simulation. In addition, the theoretical results are analyzed and discussed via comparison with experiments. Finally, the effects of the above factors are assessed, which allows us to obtain the optimal winding length, number of turns of the coil, and optimal tip additional mass. The experiment result shows that the optimized magnetostrictive harvester can output 12.07[Formula: see text]mW power to the external resistor under the condition of 1[Formula: see text]g acceleration mechanical vibration, with normalized power density reaching 40.2[Formula: see text]mW/cm3/g. Moreover, the optimized magnetostrictive harvester can successfully supply power for the LED display screen of the temperature sensor and a low-power thermometer.