压电智能梁的机电阻抗分析和损伤识别

摘要随着社会现代化进程的加快，人类工作和生活越来越依赖各种大型的工程结构，所以随着时间的推移各种结构的健康状况渐渐成为大家关心的问题。因此出于安全和经济等因素的考虑，发展无损检测技术便显得至关重要。届时随着现代化无损检测技术的发展，除了从声学、光学、电学、磁学为原理发展起来的无损检测方法，还有本文所介绍的基于压电阻抗测量技术发展起来的无损检测方法。作为现如今普遍使用的智能型材料，压电陶瓷 PZT 因其拥有体积小、寿命长和敏感性强等一系列的优点，使它成为结构健康监测元部件重要的部分（作为驱动器或传感器）。本论文也主要是研究了利用压电陶瓷机电耦合阻抗方法来识别结构中存在的损伤。论文首先讨论了压电阻抗法的国内外现状以及目前存在的不足，并将该种方法与传统无损检测方法进行了对比。阐述了压电陶瓷以及其作用机理，以及压电阻抗法的基本理论，并对不同形状的 PZT片的机电阻抗时行了数值模拟。在金属梁上粘贴PZT片，并利用阻抗分析仪分析其阻抗。通过比较不同工况下的阻抗频谱对损伤结果进行粗略地分析，然后对测得的数据进行计算，得出均方根差值（RMSD）并以此为损伤指标，验证了压电阻抗法的有效性以及可行性。最后利用 ANSYS软件对方形PZT进行了有限元(FEM)法数值模拟，证明压电阻抗法对结构损伤检测的可行性和有效性。58985
毕业论文关键词：智能材料、压电阻抗法、结构健康监测、RMSD、有限元法、数值模拟
IMPEDANCE ANALYSIS AND DAMAGE IDENTIFICATION OF PIEZOELECTRIC SMART BEAMS Abstract With the acceleration of the process of social modernization, human’s work and life increasingly rely on large engineering structures. As time goes by, health status of various structures gradually become the issues of people’s concern. Therefore, for the factors of security and economic, it’s essential to develop the techniques of Non Destructive Testing. With the development of modern NDT techniques, there is a NDT technique based on the measurement of piezoelectric impedance described in this thesis in addition to those NDT techniques based on sound, light, electricity, magnetism etc. As intelligent materials now commonly used, lead zirconate-titanate (PZT) is an important part of Structural Health Monitor elements because of its advantages such as compact size, good durability, high sensitivity etc. An Electro-Mechanical Impedance (EMI) Method based on PZT is adopted in the detection of defects existed in the thesis. Firstly, current situation of PZT impedance method is introduced, and the merits and shortcomings of the method are pointed out in the thesis. And there is a comparison of the conventional NDT methods and PZT impedance method. Secondly, piezoelectric ceramics and mechanism of its structure are introduced, the basic principle of application of the PZT impedance method is discussed in this thesis. The impedance of PZT attached to beam’s surface is measured by an impedance analyzer. By comparing different conditions of impedance spectrum, the preliminary analysis is made for the results. Then count the data measured before, obtaining RMSD as a damage criterion，which demonstrates the effectiveness and feasibility of PZT impedance method. Finally, numerical simulation is performed by ANSYS using Finite Element Method(FEM)，which also demonstrates the effectiveness and feasibility of PZT impedance method.
Key words : intelligent materials, PZT impedance method, Structural Health Monitoring, RMSD, Finite Element Method(FEM), numerical simulation

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1.1项目研究的背景和意义 . 1 压电智能梁的机电阻抗分析和损伤识别:http://www.youerw.com/wuli/lunwen_64010.html