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Structural health monitoring instrumentation, signal processing and interpretation with piezoelectric wafer active sensors.

机译：使用压电晶片有源传感器进行结构健康监测仪器，信号处理和解释。

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摘要

Structural health monitoring (SHM) is a major concern in engineering community. SHM sets out to determine the health of a structure by reading an array of sensors that are embedded (permanently attached) into the structure and monitored over time. It assets the state of structural health through appropriate data processing and interpretation, and may predict the remaining life of the structure in the long run. Most state of the art SHM techniques include E/M impedance and Lamb wave propagation approaches using piezoelectric wafer active sensors (PWAS). However, these methods require bulky, expensive instrumentation equipments, and intensive human involvement for data processing and interpretation to identify structure defects. This makes it impossible to reach long-term SHM goal and achieve in-situ and online SHM.;This dissertation is focus on instrumentation, signal processing and interpretation for SHM using PWAS.;In part I, instrumentation of impedance was extensively studied. A number of impedance measurement techniques, such as sine-correlation, cross-correlation, Fourier transform methods using stepped-sine excitations, transfer function method using synthesized broadband excitations, were explored theoretically and experimentally. Compact and low-cost impedance analyzer prototypes based on data acquisition (DAQ) devices and stand-alone digital signal processor (DSP) board were developed to replace conventional laboratory HP4194 impedance analyzer, which is always the designated instrument for E/M impedance SHM approach. Discussion on the dual use of the compact impedance hardware platform for Lamb wave propagation SHM approaches was also presented.;In part II, the dispersion issue of Lamb wave was first explored. Lamb wave dispersion compensation algorithms were studied, compared and applied to a 1D linear PWAS phased array to improve the array's resolution for damage detection. Next, theoretical basis of Lamb wave time-reversal, as a baseline-free damage detection SHM technique, was developed. The PWAS Lamb wave mode tuning effect on the time reversal procedure was studied. In addition, an adaptive signal decomposition method, i.e., matching pursuit decomposition (MPD) based on Gabor and chirplet dictionaries, was explored to automatically extract Lamb wave packet parameters, such as center frequency, time of flight (TOF). Theory of Lamb wave mode identification using chirplet MPD was developed. It correlates low-frequency Lamb wave modes (e.g., S0 and A0) with the sign of chirp rate.;Part III presents several applications to demonstrate and verify the theoretical work developed in Part I and II, including: (1) a spacecraft panel disbond detection using the newly developed impedance analyzer; (2) PWAS phased array resolution improvement using the dispersion compensation algorithm; (3) Lamb wave TOF estimation using MPD and dispersion compensation methods; (4) sparse array resolution improvement using the MPD method.;Part IV presents some novel applications with PWAS, including the utilization of PWAS as a smart sensor for crack growth monitoring under fatigue load, development of bio-PWAS resonator for monitoring capsule formation after implant, and development of high-temperature PWAS (HT-PWAS) for extreme environments.
机译：结构健康监测（SHM）是工程界的主要关注点。 SHM着手通过读取一系列传感器来确定结构的健康状况，这些传感器被嵌入（永久连接）到结构中并随时间进行监控。它通过适当的数据处理和解释来掌握结构健康的状态，并且从长远来看可以预测结构的剩余寿命。最先进的SHM技术包括使用压电晶片有源传感器（PWAS）的E / M阻抗和兰姆波传播方法。然而，这些方法需要笨重，昂贵的仪器设备，并且需要大量的人力来进行数据处理和解释以识别结构缺陷。这使得无法实现长期的SHM目标，也无法实现就地和在线SHM。本文主要研究PWAS对SHM的仪器，信号处理和解释。第一部分，对阻抗仪器进行了广泛的研究。从理论上和实验上探索了许多阻抗测量技术，例如正弦相关，互相关，使用步进正弦激励的傅立叶变换方法，使用合成宽带激励的传递函数方法。开发了基于数据采集（DAQ）器件和独立数字信号处理器（DSP）板的紧凑型低成本阻抗分析仪原型，以替代传统的实验室HP4194阻抗分析仪，后者始终是E / M阻抗SHM方法的指定仪器。还讨论了将紧凑型阻抗硬件平台用于Lamb波传播SHM方法的双重用途。第二部分，首先探讨了Lamb波的色散问题。对兰姆波色散补偿算法进行了研究，比较，并将其应用于一维线性PWAS相控阵列，以提高阵列的分辨率以进行损伤检测。接下来，开发了兰姆波时间反转的理论基础，作为无基线损伤检测SHM技术。研究了PWAS Lamb波模式调谐对时间反转过程的影响。另外，探索了一种自适应信号分解方法，即基于Gabor和chirplet字典的匹配追踪分解（MPD），以自动提取兰姆波包参数，例如中心频率，飞行时间（TOF）。建立了基于chi的MPD识别兰姆波模式的理论。它将低频兰姆波模式（例如，S0和A0）与线性调频率的符号相关联。第三部分介绍了一些应用程序，以演示和验证第一和第二部分中开发的理论工作，包括：（1）航天器面板使用新开发的阻抗分析仪进行脱胶检测； （2）使用色散补偿算法提高PWAS相控阵分辨率； （3）采用MPD和色散补偿方法的兰姆波TOF估计； （4）使用MPD方法提高稀疏阵列分辨率。;第四部分介绍了PWAS的一些新应用，包括将PWAS作为智能传感器用于疲劳载荷下的裂纹扩展监测，开发生物PWAS谐振器以监测后的胶囊形成植入和开发用于极端环境的高温PWAS（HT-PWAS）。

著录项

  • 作者

    Xu, Buli.;

  • 作者单位

    University of South Carolina.;

  • 授予单位 University of South Carolina.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 334 p.
  • 总页数 334
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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