基于光纤光栅和声波技术的材料无损检测技术研究

发布时间：2018-05-20 02:18

本文选题：超声激励 + 光纤光栅　；参考：《南京航空航天大学》2015年硕士论文

【摘要】：随着现代科学和工业的飞速发展,各种各样的材料在各个行业受到广泛的使用,材料的结构和质量越来越受到重视,因此对于材料结构的实时健康监测具有重大的意义。本文将声波技术和光纤光栅传感技术相结合起来,对复合材料板进行损伤探测可行性研究。以复合材料板为研究对象,建立了超声波材料损伤检测系统和光纤光栅信号解调系统。文章将理论和实验相结合研究了复合材料板在超声波激励作用下,用光纤光栅进行接收的损伤探测。首先叙述了材料板损伤检测的研究意义,并对当前光声相结合技术检测材料损伤的国内外研究现状做了调研。其次,对超声波理论知识进行了简要分析,说明了超声波信号在材料板中的传播特性,对实验中的超声波入射方式做了探讨。接着,研究了光纤光栅的结构和传感理论,对超声波引起的光纤光栅的应变进行了研究分析,并对超声波轴向作用于光纤光栅时的超声波反射谱偏移做了实验研究分析;然后对应变波在光纤光栅中的传播特性进行了理论说明,研究分析了光纤光栅粘贴工艺、光纤光栅的长度和光纤光栅布设如何选取和优化才能使光纤光栅最大限度的响应超声波信号。之后,利用超声激励-FBG接收的FBG波长解调方法及系统对复合材料的损伤进行了实验研究分析,详细阐述了当前常用的几种光纤光栅解调方法,阐述了各个解调方法的优缺点,对匹配光栅解调方法和激光匹配解调方法做了实验研究,将这两种系统运用于超声波信号的测量,对采集到的信号进行了对比分析,对比了两种超声波解调系统的灵敏度和解调速度,验证了光声结合方法对于材料损伤检测的可行性。最后,搭建了超声激励-光纤光栅测试系统,用超声波信号作为超声激励,水为传播介质将超声波信号传播到复合材料板上,分别用无损复合材料板和有损复合材料板进行实验对比研究,实验结果表明,可以初步判断复合材料板中的缺陷存在。
[Abstract]:With the rapid development of modern science and industry, all kinds of materials are widely used in various industries, and the structure and quality of materials are paid more and more attention, so it is of great significance to real-time health monitoring of material structures. In this paper, acoustic wave technology and fiber grating sensing technology are combined to study the feasibility of damage detection of composite plate. The ultrasonic material damage detection system and fiber grating signal demodulation system are established. In this paper, the theory and experiment are combined to study the damage detection of composite plate with fiber Bragg grating (FBG) under ultrasonic excitation. Firstly, the significance of damage detection of material plate is described, and the current research status of photoacoustic damage detection at home and abroad is investigated. Secondly, the theoretical knowledge of ultrasonic wave is briefly analyzed, the propagation characteristics of ultrasonic signal in material plate are explained, and the mode of ultrasonic incidence in experiment is discussed. Secondly, the structure and sensing theory of fiber Bragg grating (FBG) are studied, and the strain of FBG caused by ultrasonic wave is analyzed, and the ultrasonic reflection spectrum offset caused by ultrasonic axial action on FBG is analyzed experimentally. Then, the propagation characteristics of strain wave in FBG are explained theoretically, and the bonding technology of FBG is studied and analyzed. The length of fiber grating and how to select and optimize the arrangement of fiber grating can make the fiber grating respond to ultrasonic signal to the maximum extent. After that, the damage of composite material is analyzed experimentally by using the FBG wavelength demodulation method and the system, and several commonly used demodulation methods of fiber Bragg grating are described in detail, and the advantages and disadvantages of each demodulation method are expounded. The methods of matching grating demodulation and laser matching demodulation are studied experimentally. The two systems are applied to the measurement of ultrasonic signal, and the collected signals are compared and analyzed. The sensitivity and demodulation speed of two ultrasonic demodulation systems are compared, and the feasibility of photoacoustic method for material damage detection is verified. Finally, the ultrasonic excitation-fiber Bragg grating testing system is built. The ultrasonic signal is used as the ultrasonic excitation, and the ultrasonic signal is propagated on the composite plate with water as the transmission medium. The experimental results show that the defects in the composite plate can be preliminarily judged by comparing the results of the experiments with that of the lossless composite plate and the lossy composite plate.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB302.5

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