Experimental and theoretical study on vibration control of base-isolation with energy transducer

In order to evaluate the effects of structural control and energy transition for the base-isolation with energy transducer （BIET）, shaking table tests on a steel frame model （BIET system） with scale of 1：4 were conducted and the results were compared with the lead rubber beating （LRB） isolation system for the same model. Then numerical analysis of the system was carried out, in which the improved Wen analytic model was used to simulate the hysteretic law of transducers. The results show that the structural system can transform the partial earthquake energy to hydraulic energy ; furthermore, the effect of structural control can reach or be close to that of the LRB isolation system. The agreements between numerical analysis results and those of shaking table tests demonstrate the accuracy of the numerical model.

Voltage Generated Characteristics of Piezoelectric Ceramics Cymbal Transducer

In this study the relation between the generated open circuit output voltages of the piezoelectric ceramics Cymbal transducers with applied impact mechanical energy is studied. The output voltages of piezoelectric ceramics Cymbal transducers are increased with the increasing of the applied mechanical energy. Under the same impact mechanical energy, the generated open circuit output voltages of the piezoelectric ceramics Cymbal transducer is much higher than that of uncapped piezoelectric ceramics disk alone. The generated open circuit output voltages of the piezoelectric ceramics Cymbal transducer depend on the geometry parameters and the metal thickness of end-cap. The generated open circuit voltage of piezoelectric ceramics Cymbal transducer with thick metal thickness is small than that with thin metal thickness.

磁耦合式可调频压电振动俘能器

为提高压电振动俘能器的环境适应性,提出一种磁耦合式可调频压电振动俘能器,利用激励器上主动磁铁和组合换能器上被动磁铁间的耦合作用及横摆簧片实现压电振子的单向限幅激励。通过对俘能器及磁对的建模和仿真分析,获得了俘能器结构参数对俘能器输出性能的影响,在此基础上制作俘能器样机并进行实验研究,获得了俘能器纵摆质量m_(1)、横摆质量m_(2)、横向距离Lx、纵向距离Ly、竖向距离Lz及负载电阻对俘能器输出性能的影响规律。结果表明:存在两阶谐振频率f_(1)和f_(2)使输出电压出现峰值U_(n1)和U_(n2),调节m_(1),m_(2),Lx,Ly及Lz会影响f_(1),f_(2),U_(n1)及U_(n2);其他条件一定时,存在最佳负载电阻2 200 kΩ使输出功率达到0.122 mW。通过选择合适的结构参数能够提升俘能器的有效频带和输出电压,对增强压电振动俘能器的可靠性和频率适应性具有一定的参考价值。

Test and Analysis of Bridge Transducers for Harvesting Energy from Asphalt Pavement

Part of energies in asphalt pavement caused by vehicle can be converted into electric energy by piezoelectric transducer.A bridge-shaped transducer is selected to harvest energy because of its reasonable efficiency and moderate stiffness close to asphalt pavement.This paper is to compare the performance of Bridge transducers with trapezoidal,arc and arch structure through finite element analysis(FEA)and laboratory test.Results show that the arch Bridge has higher energy conversion efficiency and the trapezoidal Bridge has stronger ability to resist pressure.For arc and trapezoidal Bridge,the maximum tensile stress and shear stress are both in the inner corner of contact area between cap and PZT(lead zirconate titanate)disk.They were broken because of the cracking of PZT at the stress concentrations area.For arch Bridge,the maximum tensile stress increases with thickness of metal cap but decrease with modulus,and maximum shear stress decreases first and increases later with increasing thickness and modulus of metal cap.In laboratory test,its cracking area is shifted from edge to inner corner of contact area between cap and PZT disk with increasing thickness of metal cap.The electric potential generated by arch Bridge decreased with increasing thickness and modulus of metal cap.Under the load of 0.7 MPa,the electric potential is about 286 V for an arch Bridge transducer with 0.4mm thickness of stainless steel cap,and its storage electric energy is 0.6 mJ.The designed arch Bridge transducer is suggested as the optimum one for harvesting energy from asphalt pavement.

不同电激励方式对桥带电点火器的性能影响

为解决恒流发火在多点点火时的电源功耗和线缆能量损耗等问题,提出了采用电容放电激励方式起爆桥带电点火器,开展电容放电激励下桥带换能元的伏安特性、能量转换特性研究,并对比电容放电及恒流两种激励方式下桥带换能元的作用特性及桥带电点火器的输出特性。研究表明:采用电容放电激励起爆桥带换能元时,电容容值和充电电压的增加对桥带换能元的放电电压和电流峰值、断桥时间、能量利用率影响较大,达到桥带起爆的有效能量均为0.17J;采用电容放电激励方式时,桥带出现电爆炸现象,而采用恒流激励时桥带出现电热现象,两种不同电激励下双桥之间能量加载互不干扰;相比电容放电激励方式,采用恒流激励起爆电点火器时的建压时间、峰值压力及峰值时间均较大。

单片并联式半导体桥换能元能量转换效率影响因素分析

为了研究激励能量和桥区结构对半导体桥换能元能量转换效率的影响,设计了两种不同单片并联式桥区结构的半导体桥换能元,并在电容激励条件下进行测试,以评估并联式桥区结构的能量转换效率,进一步得到电压、桥区面积对能量转换效率的影响规律。试验结果表明:在47μF电容和25~35 V充电电压条件下,双桥区并联结构的能量转换效率略优于三桥区并联结构。在同一电容激励条件下,同一桥区结构半导体桥换能元的能量转换效率随着充电电压的增加而降低;在相同充电电压下,同一桥区结构半导体桥换能元的能量转换效率随着桥区面积的增大而提高。

一种复合型声电换能装置的优化设计

为了俘获环境中广泛存在的声能,提出一种双效应耦合作用的声电换能装置,该结构可在声电转换的同时捕获空气中的流体能量。为提高该装置的声电转化效率,对其进行优化设计。通过研究压电片不同连接方式对发电性能的影响规律,确定不同条件下系统的最优连接方式。采用正交实验法确定系统的最优组合方式,实验结果表明:在电阻大小2 MΩ、PZT材料的串联个数28个、PZT材料的总数56个、声源与换能器间的距离240 mm的组合方式下,系统输出功率最大。以最优组合设计实验,设置声压级为110 dB,噪声频率在247 Hz,此时测得负载输出电压17.54 V,输出功率307.65μW,平均能量密度13.26 mW/m3。优化后的结构可作为微小型用电器的供电电源,在新能量领域有较好的应用前景。

基于压电效应的道路振动能量俘获系统研究

针对目前车辆振动能量回收率较低的问题,为探究路面振动能量俘获技术,笔者对基于压电效应的道路振动能量俘获系统进行了研究。设计并搭建了能量俘获模拟系统,并进行了测试。首先,基于PZT-5H系列压电陶瓷设计了压电振子,并对影响压电振子能量转化效率的振动模态及支撑方式进行分析及设计;然后,对整流电路、稳压电路及储能电路进行了分析,并基于集成芯片LTC3588-1设计了外围电路,通过引脚选择3.3 V的输出电压并将其输出的电能储存在超级电容中;最后,利用激振器搭建了道路振动能量俘获模拟系统对压电振子进行了测试。LED灯的模拟负载电路验证了该能量俘获系统的可行性;激振器载荷加载试验结果表明该能量俘获系统的能量转换效率约为0.5%。

考虑永磁体偏置的超磁致伸缩换能器磁能损耗分析

研究超磁致伸缩材料的损耗特性是掌握换能器热特性与优化设计的关键,当超磁致伸缩棒材工作在永磁体偏置磁场中,内部磁畴状态变化使得材料的损耗特性发生改变,进而对超磁致伸缩换能器(giant magnetostrictive transducer,GMT)的磁能损耗计算产生了较大挑战。因此,提出考虑永磁体偏置的换能器磁能损耗计算方法,首先,基于超磁致伸缩材料磁化和磁畴理论,推导永磁体偏置条件下的超磁致伸缩换能器磁能损耗数学机理模型。然后,利用微元思想,建立考虑永磁体偏置及棒材轴向磁场分布不均匀影响下的换能器磁能损耗计算模型,并通过有限元方法验证了模型的有效性。最后,搭建超磁致伸缩换能器损耗特性测试平台,通过分析不同工况下换能器的磁能损耗特性,验证所提模型的准确性。实验结果表明:提出的考虑永磁体偏置影响下的损耗计算模型,在换能器励磁频率50~1050Hz、磁通密度幅值0.01~0.25T工况下,模型结果与实测数据的平均误差为2.93%,可有效分析超磁致伸缩换能器的磁能损耗。

Analysis on Output Power for Multi-direction Piezoelectric Vibration Energy Harvester

To predict the performance of multi-direction piezoelectric vibration energy harvester,an equation for calculating its output power is obtained based on elastic mechanics theory and piezoelectricity theory.Experiments are performed to verify theoretical analysis.When the excitation direction is along Y direction,a maximal output power about 0.139 mW can be harvested at a resistive load of 65kΩ and an excitation frequency of 136 Hz.Theoretical analysis agrees well with experimental results.Furthermore,the performance of multi-direction vibration energy harvester is experimentally tested.The results show that the multi-direction vibration energy harvester can harvest perfect energy as the excitation direction changes in XY plane,YZ plane,XZ plane and body diagonal plane of the harvester.

Design and Investigation of Energy Harvesting System from Noise

In order to survive in this modern world, electricity is an essential thing. Electricity allows us to power the technology we use every day. Without electricity, people can’t imagine their lives. As a developing country, Bangladesh still lacks electricity every day. The electricity supply to the rural areas is very poor. It is known that energy can be converted from one form to another form. As noise is the energy, it can also be converted into various forms of energy. Noise can be represented as a sound that is loud or unpleasant and causes disturbances such as street traffic sounds, construction sounds, airports, etc. Using a suitable transducer, noise (sound) energy can be transferred into a viable source of electricity generation. This can be accomplished by employing a transducer and converting noise-induced vibrations into electrical energy. Our main goal is getting enough energy, reducing the pressure of the main grid of electricity and decreasing fossil fuel imports. This paper presents the design and investigation of an energy harvesting system from noise. In this paper, an application is designed to get energy from noise by using a speaker as a transducer. Voltage has been stepped up by using a transformer, a diode which gives DC value which can be tapped into a battery and provide energy from the battery when it is needed. The embedded device was initially tested by clapping hands and tested further by using car horns. The vibrations created by car horns and other noises have been converted into electrical energy through the principle of electromagnetic induction. In total, the application produced optimal results of 0.5 - 1.0 volts which were stepped up using a transformer while maintaining the whole system being low cost and user-friendly.

Time Series-, Time-Frequency- and Spectral Analyses of Sensor Measurements in an Offshore Wave Energy Converter Based on Linear Generator Technology

Inside the second experimental wave energy converter (WEC) launched at the Lysekil research site on the Swedish west coast in March 2009 a number of sensor systems were installed for measuring the mechanical performance of the WEC and its mechanical subsystems. One of the measurement systems was a set-up of 7 laser triangulation sensors for measuring relative displacement of the piston rod mechanical lead-through transmission in the direct drive. Two measurement periods, separated by 2.5 month, are presented in this paper. One measurement is made two weeks after launch and another 3 months after launch. Comparisons and correlations are made between different sensors measuring simultaneously. Noise levels are investigated. Filtering is discussed for further refinement of the laser triangulation sensor signals in order to separate noise from actual physical displacement and vibration. Measurements are presented from the relative displacement of the piston rod mechanical lead-through, from magnetic flux in the air gap, mechanical strain in the WEC structure, translator position and piston rod axial displacement and active AC power. Investigation into the measurements in the time domain with close-ups, in the frequency domain with Fast Fourier transform (FFT) and with time-frequency analysis with short time Fourier transform (STFT) is carried out to map the spectral content in the measurements. End stop impact is clearly visible in the time-frequency analysis. The FFT magnitude spectra are investigated for identifying the cogging bandwidth among other vibrations. Generator cogging, fluctuations in the damping force and in the Lorenz forces in the stator are distinguished and varies depending on translator speed. Vibrations from cogging seem to be present in the early measurement period while not so prominent in the late measurement period. Vibration frequencies due to wear are recognized by comparing with the noise at generator standstill and the vibration sources in the generator. It is concluded that a moving average is a sufficient filter in the time domain for further analysis of the relative displacement of the piston rod mechanical lead-through transmission.

压电技术在智能道路中应用研究现状

压电技术是一种新兴的绿色能源技术,在各领域都有着广泛的应用,特别是随着智能道路的发展,压电技术在公路中的应用日渐成熟。对于压电技术在智能道路中的应用进行介绍,主要包括压电能量收集系统和混凝土结构健康监测及交通监测技术,着重分析了如何通过压电技术进行能量收集储存为周边设施提供所需电能以及监测交通流量和混凝土内部结构是否有损伤等数据,从而降低交通事故发生频率,增加道路使用时间。对压电技术目前存在的问题进行了剖析并给出了适当的建议,使压电技术能够更全面、更高效地应用在道路中。

电火工品换能元增效技术研究进展

作为电火工品的核心部件,换能元直接影响着电火工品的安全性和可靠性。电火工品结构微型化、换能信息化、序列集成化的发展趋势对于换能元提出了更高的技术要求。如何实现在低能量刺激下可靠发火,同时提升换能元的点火输出能力,即如何实现电火工品换能元的效能提升成为目前火工品换能器件研究的重要课题之一。为此,本文从换能元基底和电阻材料的优选、发火结构优化设计、自含能一体化增效以及含能薄膜复合增效等角度,综述了近年来电火工品换能元低能发火与输出增效的最新研究进展。在此基础上,讨论了未来开展换能元增效研究的重点:建立换能元材料参数基因库,借助机器学习算法等手段提高换能元发火结构优化设计的效率,针对宽带隙半导体材料等开展新换能体制的基础研究,探索含能金属有机骨架材料(Metal-Organic Frameworks,MOFs)、含能钙钛矿等新型含能薄膜材料在换能元上的集成制备。

深腔流激振荡特性研究及能量采集初步分析

针对深腔流激振荡现象的内部声场特性及其流体动能利用方法进行了研究,通过对谐振空腔内部的流场和声场进行数值模拟,探究腔体结构尺寸和流速对内部声振荡响应特性的影响,选用合适的空腔结构安装压电换能器初步实现声电能量转换过程,并进行实验验证。结果表明,当谐振腔开口尺寸H_(R)=30 mm,长度L_(R)=230 mm时,可在相当于高压输气管道的流速范围内获得属于第一水力模态和第一声学模态的稳定声振荡;当气体流速为32.26 m·s^(-1)时,声场压力振幅可达4.62 kPa;选用压电陶瓷厚度hp=1.0 mm的压电片进行实验测试,可得开路电压为1.99 V;实验结果与模型预测结果趋势一致。该方法丰富了环境流体动能的利用方式,且有望在低功耗、远距离、低维护等特殊场合的微型无线电子设备中实现无源供电。

压电陶瓷传感器监测混凝土内部缺陷的可行性研究

为监测在役混凝土结构在使用过程中的内部缺陷程度变化并定位缺陷位置,本文探索一种基于应力波的探测方法并进行试验研究,将压电传感器(PZT)以阵列形式安装在混凝土表面,将混凝土划分为不同区域,阵列中的一个传感器发射波,另一个传感器接收波,采用扫频模式和五峰值脉冲模式对混凝土不同区域进行监测。试验结果表明,当应力波通过待监测区域时,由于混凝土内部存在缺陷,应力波幅值衰减,波能降低。为了量化混凝土结构内部缺陷程度,构造基于接收信号的能量指数和损伤指数,并分别建立其与缺陷程度的函数关系,依据不同区域能量指数和损伤指数差异,确定混凝土内部缺陷存在的区域。试验结果与试件实际情况相吻合,验证了本文采用压电传感器监测混凝土内部缺陷的可行性。

双能CT扫描联合血清HMGA2和STAT3检测对早期原发性肝癌患者的诊断价值分析

目的探讨双能CT扫描联合血清高迁移率族蛋白A2(H MGA2)、信号转导和转录激活因子3(STAT3)检测对早期原发性肝癌患者的诊断价值。方法选取2019年4月~2022年4月在我院诊治的早期原发性肝癌患者95例为研究组,另外随机选取本院行上腹部CT平扫及增强扫描,但临床诊断无肝脏、脾脏等相关疾病的65例体检者作为对照组。对早期原发性肝癌患者进行双能CT扫描检查,采用酶联免疫吸附法检测血清中HMGA2、STAT3的表达水平;受试者工作特征曲线(ROC)分析血清HMGA2、STAT3对早期原发性肝癌的诊断价值,评价双能C丁扫描联合血清HMGA2、STAT3对早期原发性肝癌的诊断效能。结果双能CT扫描检查结果显示,早期原发性肝癌患者87例、非肝癌者73例,双能CT扫描诊断早期原发性肝癌的灵敏度为76.84%(73/95),特异度为78.46%(51/65),准确度为77.50%(124/160)。与对照组相比,早期原发性肝癌患者血清HMGA2、STAT3表达水平显著增高,差异有统计学意义(P<0.05)。血清HMGA2诊断早期原发性肝癌的曲线下面积为0.924(95%CI:0.871~0.960),灵敏度为85.26%,特异度为90.77%,最佳截断值为48.75mg/L5血清STAT3诊断早期原发性肝癌的曲线下面积为0.843(95%CI:0.777~0.896),灵敏度为84.21%,特异度为69.23%,最佳截断值为0.99mg/L。双能CT扫描联合血清HMGA2、STAT3诊断早期原发性肝癌的灵敏度为88.42%、特异度为89.23%,准确度为88.75%。结论早期原发性肝癌患者血清HMGA2和STAT3表达水平显著升高,双能CT扫描联合血清HMGA2、STAT3在诊断早期原发性肝癌中的诊断效能较高,临床应用价值较大。

基于流激振荡现象的流体动能收集技术研究

针对偏远地区及特殊场景下的低功耗无线传感节点电源维护不易的问题,该文对一种基于流激振荡现象的流体动能收集技术进行了研究,结合压电技术可实现流体动能转换至电能的过程。通过对流激振荡现象进行数值模拟及实验研究,分析了空腔结构中的流场及声场分布特性,探究了流体速度对声振荡频率及幅值的影响规律。利用COMSOL软件对声电转换过程进行仿真,实现了完整的流体动能-电能的转换过程。研究结果表明,在一定的速度条件下存在频率稳定的声振荡区间,可驱动压电换能装置输出频率稳定的电压,当气体流速为30.5 m/s时(相当于高压输气管道的流速范围),声场压力振幅可达6.12 kPa,对应的输出开路电压为2.62 V。当外接15 kΩ电阻时,最高输出功率可达0.29 mW。

Energy Conversion Efficiency of Rainbow Shape Piezoelectric Transducer

With the aim to enhance the energy conversion efficiency of the rainbow shape piezoelectric transducer, an analysis model of energy conversion efficiency is established based on the elastic mechanics theory and piezoelectricity theory. It can be found that the energy conversion efficiency of the rainbow shape piezoelectric transducer mainly depends on its shape parameters and ma- terial properties from the analysis model. Simulation results show that there is an optimal length ratio to generate maximum en- ergy conversion efficiency and the optimal length ratios and energy conversion efficiencies of beryllium bronze substrate trans- ducer and steel substrate transducer are （0.65, 2.21%） and （0.65, 1.64%） respectively. The optimal thickness ratios and energy conversion efficieneies of beryllium bronze substrate transducer and steel substrate transducer are （1.16, 2.56%） and （1.49, 1.57%） respectively. With the increase of width ratio and initial curvature radius, both the energy conversion efficiencies de- crease. Moreover, beryllium bronze flexible substrate transducer is superior to the steel flexible substrate transducer.

具备水下超声波测距的太阳能船舶模型设计

超声波传感器是典型的非接触传感器,由于具有抗干扰性强的优点,常常被用于测量距离。换能器将接收的声信号转换成电信号,经模数转换后,传回微控制单元。由于数据收集通常伴随噪声,所以数据采集系统需要改变和放大收集的信号,以提高数据采集的准确性。设计将水下超声波测距技术应用于船舶模型平台,利用太阳能为船舶模型提供动力,增加了技术的实用性。