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

A piezoelectric acoustic black hole absorber for rail vibration reduction and energy harvesting: Semi-analytical model

Hybrid Energy-Harvesting Systems Based on Triboelectric Nanogenerators

In order to improve the performance of cantilevered vibration energy harvesters, current methods normally vary their geometric dimensions and derive the maximum power outputs by running a full analysis. This paper attempts to optimize the structural performance of cantilevered vibration energy harvesters using a modal approach without carrying out full analysis. The effects of varying geometrical dimensions on the modal mechanical performance are analysed, which includes the analysis on rectangular cantilevered beams with and without extra mass, the convergent and divergent tapered cantilevered beams. The modal approach uses mass ratio and the modal electromechanical coupling coefficient to determine the electrical and mechanical modal performance of vibration energy harvesters. In particular, mass ratio depends on the modal participation factor, and it represents the influence of modal mechanical behaviour on the power density directly. The required modal parameters are derived using the finite element method and a distributed parameter electromechanical model is also used for comparison. The cantilevered beam designs using the modal approach can be used with different sizes with the power ranging from microwatts to milliwatts.

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

The damping ratio plays an important role in the energy acquisition and energy conversion of micro vibration energy harvester. The paper focused on damping effects of electromagnetic vibration energy harvesters and discussed the effects of the electrical damping/mechanical damping on the output performance of micro electromagnetic vibration energy harvesters. In our experiments, the damping effects on the output voltage, resonant frequency, power and efficiency of the vibration energy harvester were investigated. Both experiments and theoretical analysis suggest that the amplitude of output voltage increases firstly with electrical damping and then decreases slowly. Moreover, the increasing mechanical damping can reduce the efficiency of micro vibration energy harvesters.

Summary Vibration energy harvesting, which converts ambient vibration energy into electrical energy, has been an attractive energy scavenging technique to power wireless sensors or low power devices. Even though vibration energy harvesting has drawbacks which are relatively low harvested power and narrow bandwidth, vibration energy scavenging is one of the promising alternative power techniques in that MEMS techniques can be applied to microminiaturize the system. Therefore, many researches have been done to overcome these problems(Lee et al.2010). This paper presents improvement efficiency on piezoelectric vibration energy harvesting device to surmount issues of vibration energy harvesting. Numerical simulation and experimental test are done to validate the performance of the improved energy harvester.

Dynamic modeling and experimental study of multi-coil composite core energy harvester

Addressing synergistic low-frequency vibration isolation and energy harvesting needs in precision equipment, a coupled quasi-zero-stiffness dynamic vibration absorber system with integrated piezoelectric energy harvesting is proposed. Two configurations are established: a linear primary system with a quasi-zero-stiffness absorber (LP-QZS) and a two-stage quasi-zero-stiffness system (TQZS). Nonlinear dynamic models are developed, and approximate analytical solutions under harmonic excitation are derived via the harmonic balance method, validated by the Runge–Kutta simulations. Both systems significantly enhance low-frequency vibration isolation: TQZS reduces the primary amplitude below a QZS-primary-linear-absorber system. Piezoelectric harvesters generate substantial voltage outputs in specific frequency bands, confirming vibration-to-electric energy conversion. Parametric analysis reveals that increasing mass ratio μ simultaneously reduces the primary system amplitude and increases both the peak value and operational bandwidth of the harvested voltage in both configurations. However, the effect of damping is fundamentally different between the two configurations: In the LP-QZS system, higher damping enhances vibration suppression despite impairing energy harvesting; while in the TQZS system, it increases the primary system's amplitude and severely diminishes the harvesting output and bandwidth. In contrast, small variations in the stiffness ratio exert a negligible influence on both vibration isolation and energy harvesting performance for both systems. The parametric tuning laws elucidated in this work lay a theoretical foundation for the design of advanced integrated equipment capable of simultaneous vibration control and energy harvesting.

With the advancement of industrial automation, vibrational energy generated by machinery during operation is often underutilized. Developing efficient devices for vibration energy harvesting is thus essential. Triboelectric nanogenerators (TENGs) based on spring and cantilever beam structures show considerable potential for industrial vibration energy harvesting; however, traditional designs often fail to fully harness vibrational energy due to their structural limitations. This study proposes a triboelectric nanogenerator (TENG) based on a crank-rocker mechanism and a spring cantilever structure (CR-SC TENG), which combines a crank-rocker mechanism with a spring cantilever structure, designed for both energy harvesting and self-powered sensing. The CR-SC TENG incorporates a spring cantilever beam, a crank-rocker mechanism, and lever amplification principles, enabling it to respond sensitively to low-frequency, small-amplitude vibrations. Utilizing the crank-rocker and lever effects, this device significantly amplifies micro-amplitudes, enhancing energy capture efficiency and making it well suited for low-amplitude, complex industrial environments. Experimental results demonstrate that this design effectively amplifies micro-vibrations and markedly improves energy conversion efficiency within a frequency range of 1–35 Hz and an amplitude range of 1–3 mm. As a sensor, the CR-SC TENG’s dual-generation units produce output signals that precisely reflect vibration frequencies, making it suitable for the intelligent monitoring of industrial equipment. When placed on an air compressor operating at 25 Hz, the first-generation unit achieved an output voltage of 150 V and a current of 8 μA, while the second-generation unit produced an output voltage of 60 V and a current of 5 μA. These findings suggest that the CR-SC TENG, leveraging spring cantilever beams, crank-rocker mechanisms, and lever amplification, has significant potential for micro-amplitude energy harvesting and could play a key role in smart manufacturing, intelligent factories, and the Internet of Things.

The ambition to create self-powered microscale electrical devices motivates scientific and industrial communities to investigate the energy harvesting technique, especially working in random vibration circumstances. The mechanical response of the random vibration system may approach infinity with small probability, and then the restricted operating space of the energy harvesting system will unavoidably induce the occurrence of collision interaction. Here, the random mechanical vibration and electrical output of the vibration energy harvesting system including inelastic collision are investigated, in which the random excitation is described by Gaussian white noise, while the collision interactions are described by the transient impact model and inelastic contact model, respectively. Introducing the generalized harmonic transformation of mechanical states and adopting a slow-varying process assumption of amplitude and averaged frequency, the output voltage can be explicitly expressed as the function of displacement, velocity, and system total energy by directly integrating the linear electrical equation. The transient impact interaction is equivalent to an effective damping with energy-dependent damping coefficient, while the inelastic contact interaction is equivalent to an effective damping and an affiliated potential energy. The averaged equations with respect to mechanical energy are then derived through the stochastic averaging technique. The stationary probabilistic density function of mechanical states is established by solving the reduced Fokker–Plank–Kolmogorov equation, and then the statistical quantities of electrical voltage are obtained by the relation between voltage and mechanical states. The effectiveness and precision of the analytical procedure are validated through the results from Monte Carlo simulations, and the influence of collision interaction on the performance of energy harvesting is discussed in detail. Also, for the energy harvesting system excited by colored noise, the influence of collision interaction on the performance is evaluated through Monte Carlo simulations.

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

Mechanical Vibration Energy Harvesting and Vibration Monitoring Based on Triboelectric Nanogenerators

Performance of Linear Vibration Energy Harvesters under Broadband Vibrations with Multiple Frequency Peaks

To address the concerns of single-mode energy harvesters’ low output power and inefficient energy utilization, this paper proposes a novel piezoelectric–electromagnetic hybrid vibration energy harvester to enhance energy harvesting performance. In order to obtain the dynamic properties and evaluate the efficiency of the proposed hybrid energy harvester, an electromechanical coupling dynamic model was established, and the corresponding voltage, current, and output power of the hybrid energy harvester were calculated. The dynamical responses of the hybrid energy harvester obtained in the numerical simulations were discussed to reveal the influence of key parameters such as the excitation amplitude, load resistance, and initial magnetic distance. Then the validation experiments were conducted to verify the numerical simulation results. The results indicated that the excitation amplitude had a significant effect on the output voltage and output power. Meanwhile, the optimum load resistance and magnetic distance could boost the power generating performance of the hybrid energy harvester. The total output power of the hybrid energy harvesters can reach to 38.2 mW, which is 164.6% and 60.5% higher than those of the corresponding piezoelectric and electromagnetic energy harvesters, respectively. The results of this paper provide a new method for enhancing the performance of vibration energy harvester by means of hybrid energy conversion mechanism from an experimental and theoretical point of view.

Enhanced energy harvesting using time-delayed feedback control from random rotational environment