Experimental study on broadband bistable energy harvester with L-shaped piezoelectric cantilever beam

This paper presents an experimental study of the broadband energy harvesting and dynamic responses of an L-shaped piezoelectric cantilever beam.Experimental results show that the L-shaped piezoelectric beam generates two optimal voltage peaks when the horizontal beam size is similar to the vertical beam size.Several optimized L-shaped piezoelectric cantilever beam structures are proposed.Power generation using the inverted bistable L-shaped beam is better.It is observed experimentally that the inverted bistable L-shaped beam structure shows obvious bistable characteristics and hard spring characteristics.Furthermore,the corresponding relationship between the bistable phase portrait and the potential energy curve is found in the experiment.This is the first time that a phase portrait for stiffness hardening of an L-shaped beam has been found experimentally.These results can be applied to analysis of new piezoelectric power generation structures.

ACTIVE VIBRATION CONTROL OF A CANTILEVER BEAM USING PIEZOELECTRIC SENSORS AND ACTUATORS

The topic of vibration control with distributed actuators has been the subject of many researches. This paper is concerned with the vibration control of a cantilever beam equipped with piezoelectric ceramics as sensors and actuators. One piezoelectric ceramic is bonded to the structure and provides control input for the structure, while the other piezoelectric ceramic provides the feedback signal. An approach to identification and control is presented. Observation spillover is eliminated by prefiltering the sensor data. A procedure used to determine actuator and sensor location, is discussed based on the modes to be controlled. Finally, the experimental results are presented to verify the proposed method.

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.

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.

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 power performance improvement of a piezoelectric energy harvester for low-frequency vibration environment

A novel oscillator structure, bimorph piezoelectric cantilever beam with two-stepped variable thicknesses,is proposed to improve the energy harvestingperformance of the vibration energy harvester (VEH) under low-frequency vibration environment. Firstly, the piezoelectric cantilever is segmented to obtain the energy functions based on the Euler-Bernoulli beam assumptions, and the Galerkin approach is utilized to discretize the energy functions. Applying boundary conditions and continuity conditions enforced at separation locations, the electromechanical coupled governing equations for the piezoelectric energy harvesterareintroduced by means of the Lagrange equations. Furthermore, the steady state response expressions are obtained for harmonic base excitations at arbitrary frequencies. Numerical results are computed and the effects ofthe lengths-ratio, thicknesses-ratio,end thicknessand load resistance on the output voltage, harvested power and power density are discussed. Moreover, to verify thecorrectness ofanalytical results, the finite element method (FEM)simulationis also conducted to analyze performance of the proposed VEH, where a good agreement is presented. All the results show thatthe present oscillator structureis moreefficient than the conventional uniform beam structure, specifically, for vibration energy harvesting in low-frequency environment.

Piezoelectric Energy Analysis on Diverse Buoy Coupling with Hydrodynamic Parameters

This paper mainly describes the influence factors of the captured energy power by huge wave energy harvesters, in which the vertical motion of buoy can transform ocean’s potential energy into piezoelectric energy power by undulating waves. Firstly, related environmental coefficients are analyzed by means of the incident wave theory. Besides, the geometric structural parameters are also analyzed and compared under optimal environmental coefficients with semi-analytical solutions. Thirdly, the numerical results also show the impact trend of hydrodynamic parameters and geometric volume on motion, voltage and power with qualitative agreement. The numerical simulation confirms that the improved structure parameters could markedly deliver sufficient power under the same conditions with long-time stability.

Bending analysis of a functionally graded piezoelectric cantilever beam

A new analysis based on Airy stress function method is presented for a functionally graded piezoelectric material cantilever beam. Assuming that the mechanical and electric properties of the material have the same variations along the thickness direction, a two-dimensional plane elasticity solution is obtained for the coupling electroelastic fields of the beam under different loadings. This solution will be useful in analyzing FGPM beam with arbitrary variations of material properties. The influences of the functionally graded material properties on the structural response of the beam subjected to different loads are also studied through numerical examples.

采集人体能量的压电能量收集器研究进展

采集人体能量的压电能量收集器具有可持续性、便携性、环保型和经济性等优势,已引起了人们的广泛关注。该文综述了压电能量收集器在人体能量采集领域的最新研究进展,包括用于人体能量采集的压电能量收集器的设计、更适用于穿戴或植入的压电材料的选择、以及新工艺对人体压电能量收集器性能的改善等。在传统能源日益匮乏的今天,人们对能量收集器的环保性以及可自供能的穿戴设备提出了更高的要求,未来的人体用压电能量收集器将面临更多的机遇与挑战,应着眼于新材料、新技术、新工艺的开发,推动压电能量收集器的发展,使其能更好地适应不同的应用,提高人体能量收集效率。

一种高功率密度的直角螺旋压电能量收集器

为了实现振动环境下的高效能量收集,研制了一种高功率密度的直角螺旋悬臂梁压电能量收集器。分析了不同悬臂梁弧度的压电能量收集器的应力分布,研究了不同悬臂梁弧度的压电能量收集器的谐振频率、开路电压和输出功率。研究结果表明,随着悬臂梁弧度的增大,能量收集器谐振频率逐渐减小,但是内部阻抗逐渐增大,其中悬臂梁弧度为2πrad的直角螺旋能量收集器的输出性能最好。通过实验测试发现,在0.1g的加速度激励下,悬臂梁弧度为2πrad的直角螺旋能量收集器的谐振频率为265 Hz、开路电压为1.8 V,当负载为140 kΩ时,实现最大输出功率为5.79μW。与其他不同结构的压电能量收集器相比,该直角螺旋结构收集器在满足供电需求前提下,还具有较高的功率密度,在便携式微电子器件供电和工业设备故障检测方面有广阔的应用前景。

基于CBAM-CNN和压电悬臂梁的温度解耦质量感知方法

悬臂梁结构广泛用于微小质量测量,而温度变化会引起测量结果漂移。传统测量方法需要在温度稳定的环境中进行,但实际应用中通常难以满足此要求,且温度漂移对测量的影响难以直接解耦。本文提出了一种基于数据驱动,CBAM-CNN和压电悬臂梁的自适应温度解耦质量感知方法。首先,搭建谐振式压电悬臂梁温控测量平台采集不同质量负载下的阻抗响应信号,设计自适应加权预处理方法以增强结构特征并突出有限样本中的关键信息;其次,设计基于混合领域注意力机制的CBAM-CNN网络来评估信号中多个谐振峰的相对关系,实现温度解耦和质量感知。实验结果表明,该方法在25℃至55℃的温度范围内的对0.1~1 g的质量感知准确率高达99.70%,无需进行温度补偿即可实现大跨度温度下的精确质量感知。

一种“回”字形多方向压电能量收集方法

该文介绍了一种“回”字形的多方向微型压电振动能量收集装置,其由尺寸为34 mm×2 mm×1 mm的正方形边框包围,内部结构包含4个非对称的组合悬臂梁,主悬臂梁固定于边框内壁,并与z方向垂直,次悬臂梁连接在主悬臂梁的末端质量块上。首先建立基础激励条件下组合悬臂梁振动系统的动力学模型。然后,通过有限元仿真分析对比了不同刚度和质量对位移幅值的影响,验证了组合悬臂梁系统的振动特性,并确定了最佳结构参数值:当主、次悬臂梁厚度均为0.3 mm,主、次质量块的最佳惯性质量分别为619.32 g、342.3 g。经仿真计算得到z方向可输出电能功率为3.1385 mW,x、y方向可输出功率均为0.7205 mW。最后搭建微型能量收集器实验平台,在实际测试中z方向的输出功率为2.85 mW,x、y方向的输出功率均为0.57 mW。

谐振式耦合悬臂梁力传感器设计与检测性能分析

谐振式力传感器的检测性能取决于谐振敏感元件的几何尺寸、结构形式和传感机制,目前,单纯依靠减小尺寸提高检测性能的方法已经处于瓶颈期。为了研究发展新型谐振式力传感器,协调非线性振动与谐振结构检测性能之间的矛盾,从而探索灵敏度更高的传感机制,提高其检测性能,提出了一种压电驱动的谐振式磁耦合悬臂梁力传感器。首先,对磁耦合悬臂梁的结构进行了设计和理论建模,通过理论分析了外界压力对磁耦合悬臂梁结构振动特性的影响,随着压力增大,磁耦合悬臂梁之间的距离减小,谐振频率增大。其次,实验验证了分岔跳跃动力学行为的优点,相比单根谐振梁共振时的最大振幅提高了2.8倍,然后研究了基于分岔跳跃特性和基于倍频响应的两种压力检测方案,分别利用分岔跳跃时的临界频率与模态耦合时高阶响应频率实现了压力检测,并对灵敏度和线性度进行了分析。实验结果表明,基于分岔跳跃特性的检测方案振幅变化明显,是基于倍频特性检测方案的5倍左右,易于检测,克服了非线性因素带来的不良影响;基于倍频响应的检测方案输出灵敏度高,是基于分岔跳跃检测方案的4倍左右,信噪比大,为设计不同检测原理的谐振式力传感器提供了一定的参考价值。

多向振动俘能器设计及能量收集实验研究

针对线性、单一的振动能量俘能器存在工作频带狭窄、只能采集单向振动等问题,该文提出了一种适应货运列车等多向振动应用场景的新型多向振动俘能装置,以增强对环境中振动能量的俘获。该装置结合压电和电磁俘能器,通过螺旋圆柱弹簧和顶端质量有效捕获多向振动,并通过磁力传递振动能量至压电梁。合理设计了弹簧-质量结构,使其在较低的频率范围内可实现多种振动模态,拓宽了俘能器的谐振频带。为了充分利用压电材料,采用了变宽度压电悬臂梁,使应力均匀分布。压电梁自由端的永磁体随着压电梁的振动而产生变化的磁场,在线圈中产生感应电压。通过有限元分析和实验测试,验证了复合式俘能器可以采集多向振动能量,并测试了在z向振动激励下压电、电磁及复合式俘能器的最大输出功率。在频率9.5 Hz、z向振幅2 mm的正弦波激励下,复合式俘能器输出最大功率为3.276 mW。该系统在理论上可为低功耗传感器提供持续电力,为机械能收集与能量转换领域提供技术支持。

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.

基于同步翻转电荷提取的压电能量俘获电路设计

提出了一种高效自供电同步翻转电荷提取(SP-SICE)电路,该电路具有无需整流桥,且能自供电的特点。电路采用下拉电阻设计改进了翻转倍压结构,减少了因电感感抗产生的能量消耗问题,提高了翻转倍压时的能量收集效率。实验结果表明,高效SP-SICE电路平均稳定输出功率是标准能量俘获(SEH)电路的2.76倍,是SICE电路的1.44倍。

阵列压电式能量采集器仿真研究与实验分析

以传统单悬臂梁为基础设计的压电式振动能量采集器存在输出电能低和工作频带窄等不足,为此,设计了阵列压电式振动能量采集器,并进行了仿真研究和实验分析。首先对压电悬臂梁工作原理进行了理论分析,通过建立等效电路模型推导出了输出功率和输出电压公式;然后从静力学角度和振动模态角度两方面对阵列压电式振动能量采集器进行了COMSOL仿真分析,得到了采集器基本振动特性;最后,制作实验样机并搭建实验平台,对样机进行了串联输出和并联输出性能测试。结果表明:共用质量块压电阵列结构虽然输出电能得到了提升,但工作频带相较于单压电悬臂梁并无拓宽,因而使用受限;带不同质量块压电阵列结构的串联输出最大开路电压为1.79 V,带宽为7.6 Hz,并联输出最大开路电压为1.71 V,带宽为8.6 Hz,而相同实验环境下的单梁最大开路电压为1.56 V,带宽为2.4 Hz,故采集器输出性能和工作频带均得到改善,环境适应能力得到增强。

压电俘能结构力-电耦合特性有限元仿真分析

基于有限元方法对压电悬臂梁进行力电特性数值仿真,研究了不同截面形状压电悬臂梁的力-电特性,发现相比于矩形压电悬臂梁,梯形压电悬臂梁有较高的输出电压和一阶共振频率。进一步分析了梯形压电悬臂梁的压电片长度、压电片位置、基板-压电片厚度比对其性能的影响。结果表明,当压电片长度越短,且位置越靠近固定端时,梯形悬臂梁的输出性能越好,但一阶共振频率随着压电片长度的减小和与固定端距离的增加而降低;当基板-压电片厚度比为1.6时,梯形悬臂梁的电学输出特性最佳,一阶共振频率随着厚度比的增大而增大。

压电式种子计数系统

提出了一种基于压电传感器的种子数粒系统,该系统用悬臂梁结构感受种子冲击以及用压电元件将冲击转换为电信号,经过放大整形后变成脉冲信号输入单片机计数并显示。根据典型的弹簧-质量-阻尼系统的二阶传递函数理论,对系统阻尼振动频率和阻尼比进行了分析。选用合适的高分子材料和安装方式,使系统拥有较好的阻尼比,种子短暂的冲击作用变换为单个波峰电压信号以实现准确计数。实验室试验结果表明,数粒系统单粒测量误差小于0.4%。

压电智能柔性梁振动主动控制研究

利用压电陶瓷作为作动器 ,对柔性悬臂梁进行了振动主动控制研究 .分析了压电结构振动主动控制的原理和方法 .采用独立模态控制法对柔性悬臂梁的前两阶模态实施主动控制 .实验结果表明 ,通过振动主动控制明显增加了柔性悬臂梁的结构阻尼 ,取得了十分有效的振动抑制效果 .