Analysis of chaos behaviors of a bistable piezoelectric cantilever power generation system by the second-order Melnikov function

By applying the second order Melnikov function, the chaos behaviors of a bistable piezoelectric cantilever power generation system are analyzed. Firstly, the conditions for emerging chaos of the system are derived by the second order Melnikov function. Secondly, the effects of each item in chaos threshold expression are analyzed. The excitation frequency and resistance values, which have the most influence on chaos threshold value, are found. The result from the second order Melnikov function is more accurate compared with that from the first order Melnikov function. Finally, the attraction basins of large amplitude motions under different exciting frequency, exciting amplitude, and resistance parameters are given.

Dynamic responses of a piezoelectric cantilever plate under high-low excitations

In this paper,the nonlinear dynamic responses of a piezoelectric cantilever plate near the first-order and second-order natural frequencies under the action of electromechanical coupling are studied by experiments and finite element(FE)methods.The influence of different excitation frequencies on the dynamical characteristics of piezoelectric cantilever plates is analyzed with the fixed excitation amplitude.First,an experimental setup is built,including a carbon fiber cantilever plate attached to a macro fiber composite(MFC)sheet.Then,the electromechanical coupling excitations are subjected to the plate with different frequencies,which are chosen near the first and second-order natural frequencies of the plate.The piezoelectric cantilever plate has periodical motions under a lower frequency excitation,and the motions of the plate become more complex after another high frequency excitation added in the physical field.The experimental results show that the motion of the piezoelectric cantilever plate changes from stable to unstable with high-low coupled resonant frequencies.At last,the FE study is carried out to compare and verify the experimental results and the effects of isotropic and orthotropic materials on the accuracy of natural frequencies results are also compared.

An energy harvester combining a piezoelectric cantilever and a single degree of freedom elastic system

This paper presents a type of vibration energy harvester combining a piezoelectric cantilever and a single degree of freedom (SDOF) elastic system. The main function of the additional SDOF elastic system is to magnify vibration displacement of the piezoelectric cantilever to improve the power output. A mathematical model of the energy harvester is developed based on Hamilton's principle and Rayleigh-Ritz method. Furthermore, the effects of the structural parameters of the SDOF elastic system on the electromechanical outputs of the energy harvester are analyzed numerically. The accuracy of the output performance in the numerical solution is identified from the finite element method (FEM). A good agreement is found between the numerical results and FEM results. The results show that the power output can be increased and the frequency bandwidth can be improved when the SDOF elastic system has a larger lumped mass and a smaller damping ratio. The numerical results also indicate that a matching load resistance under the short circuit resonance condition can obtain a higher current output, and so is more suitable for application to the piezoelectric energy harvester.

Theoretical analysis of dynamic property for piezoelectric cantilever triple-layer benders with large piezoelectric and electromechanical coupling coefficients

Ferroelectric single crystals,such as PZN-PT,provide novel prospects in piezoelectric bending devices such as actuators,sensors or energy harvesters because of their extraordinarily large piezoelectric coefficients.However,large errors may occur in some analyses on electromechanical behaviors using the conventional models.We find the bending rigidity of piezoelectric composited bender is affected not only by thickness,width and the modulus of elasticity of the different layers but also electromechanical coupling coefficients(EMCCs)of the piezoelectric material and the larger EMCCs mean more marked effect.This paper focuses on the derivation of the applied input excitation and output response characteristics in the circular frequency domain for piezoelectric cantilever triple-layer benders(PCTBs),taking into account the secondary piezoelectric effect.Analytic dynamic descriptions of such actuators and transducers are obtained.Based on the presented models dynamic features of PCTB composed of PZN-8%PT are calculated,and numerical results coincide with simulations using the finite element method(FEM).

Experiment and performance analysis of serpentine-shaped cantilever beam for pipeline vibration-based piezoelectric energy harvester prototype development

Pipelines produce vibrations during fluid or gas transportation.These vibrations are less likely to cause structural failure as they exist with a small magnitude and can be harvested into useful energy.This paper presents a study on the piezoelectric energy-harvesting method converting mechanical energy from pipeline vibration into electrical energy.The performance of the serpentine-shaped piezoelectric cantilever beam was observed to check whether the design can produce the highest output voltage within the allowable vibration region of the pipeline from 10 to 300 Hz through finite element analysis using COMSOL Multiphysics software(Supplementary Material).In addition,this study investigates the energy-harvesting potential of the proposed design under real pipeline vibration conditions through a lab vibration test.The harvested energy output is evaluated based on various vibration frequencies and amplitudes,which gives an idea of the device and its performance under different operating conditions.The experiment result shows that the energy harvester produced an open-circuit voltage of 10.28-15.45 V with 1 g of vibration acceleration.The results of this research will contribute to the development of efficient piezoelectric energy harvesters adapted for pipeline environments.

Modeling and analysis of piezoelectric beam with periodically variable cross-sections for vibration energy harvesting

A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule （GDQR） method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight.

Analytical and finite-element study of optimal strain distribution in various beam shapes for energy harvesting applications

Owing to the increasing demand for harvesting energy from environmental vibration for use in self-powered electronic applications, cantilever-based vibration energy harvesting has attracted considerable interest from various parties and has become one of the most common approaches to converting redundant mechanical energy into electrical energy. As the output voltage produced from a piezoelectric material depends largely on the geometric shape and the size of the beam, there is a need to model and compare the performance of cantilever beams of differing geometries.This paper presents the study of strain distribution in various shapes of cantilever beams, including a convex and concave edge profile elliptical beam that have not yet been discussed in any prior literature. Both analytical and finite-element models are derived and the resultant strain distributions in the beam are computed based on a MATLAB solver and ANSYS finite-element analysis tools. An optimum geometry for a vibration-based energy harvesting system is verified.Finally, experimental results comparing the power density for triangular and rectangular piezoelectric beams are also presented to validate the findings of the study, and the claim, as suggested in the literature, is verified.

A preliminary research on wireless cantilever beam vibration sensor in bridge health monitoring

According to specific bridge environment, optimal design piezoelectric cantilever beam structure by using results of theoretical calculations and simulation, verify natural frequencies of piezoelectric cantilever beam and production ability of data by experiment, thus formed a complete set of design method of piezoelectric cantilever beam. Considering natural frequency of vibration and intensity of the beam body, design a new type of piezoelectric cantilever beam structure. Paper analyzes the principle of sensor data acquisition and transmission, design a hardware integration system include signal conversion module, microcontroller module and wireless transmission module, test local read and wireless transmission for the combination structure of cantilever beam and data collection card, experimental verification of the radio piezoelectric vibrating cantilever vibration response is intact, the beam produced signal by vibration, acquisition card converts and wireless transmit data, this proved a good and intuitive linear response in simulation of bridge vibration test. Finally, the paper designed a kind of new wireless sensor of vibration cantilever beam, suitable for small bridge health monitoring based on Internet of things.