尺度效应下单层压电微换能器的特性研究

发布时间：2018-03-07 06:16

本文选题：压电微换能器　切入点：静态特性　出处：《南京理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：l本论文对单层压电微换能器的特性进行了研究,包括静态特性及动态特性。本文所研究的换能器是悬臂梁式,并为层合梁,包含压电层、被动层及上下电极层,前者的厚度在微尺度下。首先强电场激励下压电层发生弯曲时,必须要考虑压电材料的电致伸缩效应,这将使得压电方程中出现非线性项,即电场强度的平方项。其非线性随电场强度而改变,电场增大则相应增大。实验表明：当结构的特征尺寸在微尺度时,其力学特性对特征尺寸有着很大的依赖性,与宏观尺寸下显著不同,这种特性被称为尺度效应。因此在这篇文章中将会运用偶应力理论来研究该换能器在尺度效应下的静态应变。最后,由于悬臂梁式的弯曲换能器一般工作在其弯曲振动的谐振频率附近,因此,为了得到换能器的最佳性能,需要深入研究其动态特性。本文中运用模态分解来分析换能器动态机电响应,并使用MATLAB软件对该响应进行数值模拟。结果显示：当压电层的厚度处在微米尺度时,换能器压电层的无量纲刚度会发生显著增加,这将影响换能器的谐振频率,导致换能器一阶模态下的电荷和电压输出相应的减少。
[Abstract]:In this paper, the characteristics of single-layer piezoelectric microtransducer are studied, including static and dynamic characteristics. The transducer studied in this paper is cantilever beam, and laminated beam, including piezoelectric layer, passive layer and upper and lower electrode layer. The thickness of the former is in the microscale. Firstly, when the piezoelectric layer bends under the strong electric field, the electrostrictive effect of the piezoelectric material must be considered, which will lead to the nonlinear term in the piezoelectric equation. That is, the square term of electric field intensity. Its nonlinearity changes with the electric field intensity, and the electric field increases accordingly. The experimental results show that when the characteristic size of the structure is in the micro scale, the mechanical properties of the structure are greatly dependent on the characteristic size. In this paper, the static strain of the transducer under the scale effect will be studied by using the theory of couple stress. Because the cantilever beam type bending transducer generally works near the resonant frequency of its bending vibration, therefore, in order to obtain the best performance of the transducer, In this paper, modal decomposition is used to analyze the dynamic electromechanical response of the transducer, and a numerical simulation is carried out by using MATLAB software. The results show that when the thickness of the piezoelectric layer is in the micron scale, The dimensionless stiffness of the piezoelectric layer of the transducer will increase significantly, which will affect the resonant frequency of the transducer, resulting in the corresponding reduction of the charge and voltage output in the first mode of the transducer.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB552

【参考文献】