Cymbal型压电换能器电压-位移特性建模与分析

通过对Cymbal换能器压电陶瓷片受力分析,给出了其压电方程的边界受力约束条件,建立了Gymbal型压电换能器电压-位移函数关系模型.模型计算结果与试验结果吻合.并利用该模型,给出了Cymbal换能器几个关键参数对等效压电常数de33的影响规律.这些结论对Cymbal换能器的敏感参数误差控制、大批量生产工艺优化、性能指...     

基于压电复合材料的二维面阵超声换能器性能研究

采用锆钛酸铅陶瓷基环氧树脂1—3复合压电材料,制作了一种64(8×8)阵元二维面阵超声换能器,并对其进行性能研究.实验测试表明:二维面阵超声换能器一致性良好,回波带宽为40.8％,中心频率为5.0 MHz,与理论设计的3.5 MHz中心频率保持基本一致.对二维面阵超声换能器的声场进行仿真模拟和表征,验证了该超声换能器产...     

汽车行驶减振带振动发电仿真研究北大核心CSCD

为了有效地采集减速带振动的能量,提出了一种采用Cymbal换能器的机电转换装置。汽车通过的压力经减速带传递到换能器使其产生轴向和径向位移,通过压电效应将机械能转化成电能。根据振动力学建立车辆减速带和压电换能器的耦合振动模型,利用压电学原理研究了机电转换理论,运用Newmark算法对发电系统输出电能进行仿真。仿真结果表明,所建模型能将振动机械能转换为电能,当车辆以10 km/h通过时最大会产生204.78V的电压和0.768mW的功率。对于开拓减速带发电新思路具有借鉴意义。     

压电陶瓷换能器收发系统幅频特性建模与分析验证

压电陶瓷超声波系统是实现物体探测的重要方法。本文基于压电陶瓷换能器收发系统的等效电路模型,通过引入声波衰减系数建立了发射换能器激励电压与接收换能器输出电压间的关系,并求解出了该等效电路模型的传递函数。实测数据与传递函数仿真数据对比表明,收发系统幅频特性的仿真曲线与实测曲线基本一致,验证了所给等效电路模型与传递函数的正确性。     

压电换能器耗散因子的等效电路参数表示

压电换能器的耗散因子是评估其性能的重要参数,但已有的测量方法实现困难。文中提出一种通过压电等效电路参数来获得压电材料的三种耗散因子（介电耗散因子、弹性耗散因子和压电耗散因子）的方法。通过首先建立引入复电弹常数后的压电等效电路,推导了由复电弹常数的实部和虚部描述的等效电路参数。根据耗散因子的定义,推导了耗散因子同等效电路参数间的关系。通过测量等效电路参数得到了PZT压电陶瓷耗散因子的温度及应力响应特性曲线。     

一种高频宽带水声换能器的研制

研制了一种宽带、高频压电复合材料圆环阵水声换能器.该换能器的宽带结果是通过采用降低压电材料机械品质因数Qm值和多模耦合振动两种方法实现的.通过径向切割压电陶瓷圆环、灌注环氧树脂得到压电复合材料圆环,再将不同壁厚的压电复合材料圆环轴向叠堆而成敏感元件,对敏感元件进行模具封装,引出电极引线,得到换能器.利用ANSYS软件对结构进行仿真,得到敏感元件谐振频率和带宽随压电陶瓷圆环厚度、高度和平均半径的变化规律,并根据仿真结果确定了换能器敏感元件的最优设计方案.将由最优参数得到的两个压电复合材料圆环轴向叠堆,制作了双圆环叠堆复合材料换能器.经测试,该换能器形成了明显的双模耦合振动,该换能器谐振频率为375 kHz,其-3 dBd工作带宽为90 kHz,最大发送电压响应达148 dB.实现了换能器的高频、宽带、水平全向发射声波的设计目标.     

Spherical-Cymbal换能器位移特性有限元分析

提出了一种新型的Spherical-Cymbal压电复合换能器,Spherical-Cymbal换能器由厚度方向极化的压电陶瓷薄圆片夹持在两个球形金属端帽之间制成.每个金属端帽内表面均有一个浅球冠形空腔,球形金属端帽起机械放大作用,它将压电陶瓷薄圆片的微小径向位移转换并放大为垂直其表面的较大的轴向位移.分析了影响Spherical-Cymbal换能器轴向位移性能的几何因素及物理因素,采用ANSYS软件对Spherical-Cymbal换能器位移特性进行了仿真.     

智能结构中压电元件双向换能效率的仿真研究

根据压电振子机电换能等效图,得出压电超声换能器等效二端口网络模型,由此推导了智能结构中压电换能器的双向换能函数.仿真实验表明,驱动-传感换能器对的双向换能效率随负载声阻抗的增大先升高后降低.为提高换能效率,可以采用匹配声阻抗法.     

线形超声相控阵换能器的阵列设计

超声相控阵检测技术是利用脉冲反射法对被检构件中是否存在缺陷(如裂纹、夹杂、气孔等)进行无损检测,阵列换能器是该检测技术中实现电-声转换的传感器件,其声场特性是能否获得并有效利用被检测部位或区域回波信息的决定因素,也是设计换能器阵的主要依据。从平面矩形活塞阵元的辐射声场出发,利用简便算法对阵元辐射声场、一维线阵辐射声场进行了仿真模拟,分析了影响阵列换能器性能的几个主要因素,提供了阵列换能器的设计思路,并对采用相控阵超声换能器与常规超声换能器探测人工缺陷时的扫查波形进行了比较。     

Cymbal型复合压电作动器微进给技术研究

针对普通压电作动器行程较短的缺点,提出一种具有Cymbal结构的复合压电陶瓷作动器的结构设计。通过将压电陶瓷微小的径向位移放大,转换成轴向位移,扩大了作动器的行程。在作动器控制系统设计中,一方面在硬件结构设计中引入了高精度的位移传感器闭环反馈系统,另一方面通过对作动器的输出进行软件补偿的方法,消除了Cymbal型复合压电作动器自身存在的输出磁滞性和非线性的缺点,大幅度提高了系统的开环控制特性,实现了对作动器的高精度控制。实验结果证明系统设计有效。     

Lead-free piezoceramic cymbal actuator

Lead-free piezoelectric ceramic 0.90(Bi_1/2Na_1/2)TiO₃-0.05(Bi_1/2K_1/2)TiO₃-0.05BaTiO₃ (abbreviated as BNT-BKT-BT5) is used as the driving element in a cymbal actuator with titanium endcaps. Both the electrical and mechanical properties of the lead-free piezoceramic cymbal are compared with that of the lead zirconate titanate (PZT) cymbal. It is found that the performance of the lead-free ceramic cymbal actuator is comparable to those fabricated using hard PZT ceramic driving element because BNT-BKT-BT5 has reasonable piezoelectric coefficients and low density.     

A novel snap-through buckling behaviour of axisymmetric shallow shells with possible application in transducer design

In this study, the snap-through buckling behaviour of axisymmetric shells, subjected to axisymmetric horizontal peripheral load or displacement for various shell parameters and various boundary conditions, is investigated. Results obtained seem not to have been reported previously. An application of peripheral displacement type of loading is seen in metal-ceramic composite transducers developed by sandwiching a piezoelectric (PZT) ceramic between two metal end caps which serve as mechanical transformers for converting and amplifying the lateral displacement of the ceramic into an axial motion normal to the metal cap. In our numerical search, we have observed that snap-through and snap-back buckling is possible for shallow spherical caps for a very narrow range of the shell parameter used. When a hole is opened around the apex of the cap, buckling is possible for a larger range of the shell parameter. Obtaining the displacement amplification and the blocking or generative force for various material and geometric properties is necessary for the possible application of the findings in transducer design. The numerical results are presented in graphical forms.     

Structural damage identification for thin plates using smart piezoelectric transducers

An impedance-based structural damage identification method for thin plates is presented in this paper using piezoelectric ceramic (PZT) transducers. The local damages are characterized by introducing a damage parameter in each finite element. A two-dimensional electromechanical impedance model is proposed to predict the electric admittance of the PZT transducer bonded to the plates. The general equations for generating structural dynamic stiffness from normal modes are formulated based on finite element analysis. The first-order perturbation method is introduced to obtain the electric admittance change on PZT transducers due to damage. A damage identification scheme for solving nonlinear optimization problem is proposed to locate and quantify the damage by matching the numerical and experimental electric admittance change on PZT transducers. The proposed technique is verified through numerically simulated damage identification tests.     

Tonpilz型压电陶瓷超声传感器的设计

超声传感器是一种电声转换器件,其敏感元件压电陶瓷控制传感器的主要性能。设计了一种谐振频率为140 kHz的Tonpilz型压电陶瓷超声传感器,从压电方程入手,建立了不同的理论模型,对等效网络法和有限元法2种不同的设计方法进行了比较。相应的试验表明:有限元法的分析结果直观明了、建模快捷、分析准确,其误差可控制在5%以内。设计研制的Tonpilz型传感器工艺简单、造价低廉、性能稳定。     

VHF single-crystal silicon elliptic bulk-mode capacitive disk resonators-part I: design and modeling

This work, the first of two parts, presents the design and modeling of VHF single-crystal silicon (SCS) capacitive disk resonators operating in their elliptical bulk resonant mode. The disk resonators are modeled as circular thin-plates with free edge. A comprehensive derivation of the mode shapes and resonant frequencies of the in-plane vibrations of the disk structures is described using the two-dimensional (2-D) elastic theory. An equivalent mechanical model is extracted from the elliptic bulk-mode shape to predict the dynamic behavior of the disk resonators. Based on the mechanical model, the electromechanical coupling and equivalent electrical circuit parameters of the disk resonators are derived. Several considerations regarding the operation, performance, and temperature coefficient of frequency of these devices are further discussed. This model is verified in part II of this paper, which describes the implementation and characterization of the SCS capacitive disk resonators.     

埋入压电材料的机敏混凝土研究

用有限元方法对混凝土模块及埋入其中的压电陶瓷在混凝土试件受到外载荷作用时的应力分布进行了分析.分析结果表明,埋人的压电陶瓷元件上的应力与模块所受外载荷之间存在着线性关系.在对机敏昆凝土试件进行的加载实验中,通过测量埋入的压电陶瓷元件的等效电路参数,根据耗散因子同等效电路参数间的关系,得到了压电陶瓷三种耗散因子随载荷的响应特性.加载实验结果和数据误差分析表明,压电耗散因子与试件外部载荷之间存在一定的规律性和较好的稳定性.验证了将陶瓷元件直接埋入混凝土结构内部检测结构内应力,是一种可行的,实现对混凝土结构安全进行实时、在线、主动的检测方法.     

一种确定磁致伸缩换能器电气模拟参数的方法

通过对磁致伸缩换能器的电气模拟电路进行分析,研究了圆图概念在确定其电气模拟参数的应用,提出了用曲线拟合先求磁导率,再求其电气参数的方法,该方法相对传统的"谐振-反谐振"实验法能更准确地确定磁致伸缩换能器的电气模拟参数。此方法是一种新型的确定磁致伸缩换能器电器模拟参数方法,其在磁致伸缩换能器研究及应用领域具有一定的实用价值。