【作者】 王长坤；

【导师】 袁慎芳；

【作者基本信息】 南京航空航天大学 ， 测试计量技术及仪器， 2007， 硕士

【摘要】 航空航天结构的连接处是容易发生螺钉连接失效的部位,为了防止结构损伤所带来的灾难或损失,必须对结构进行有效的监测。光纤布拉格光栅传感器由于体积小、重量轻、抗电磁干扰、可波分复用以及波长编码等优点,可用来监测航空航天结构的应变和损伤,在航空航天结构健康监测领域中有着广阔的应用前景。本文以航空航天结构健康监测需求为背景,以加筋板为研究对象,针对螺钉连接失效的安全性问题,研究了一套基于光纤光栅应变测量的健康监测系统。本文首先阐述了本课题的研究背景,包括结构健康监测和光纤布拉格光栅的概述,以及国内外基于光纤光栅的结构健康监测的研究现状。其次,阐述了光纤布拉格光栅的工作原理,在此基础上对光纤光栅传感应用的一些技术要点进行了探讨。接着,介绍了加筋板连接失效监测系统的基本组成和连接失效的模式分类定义,主要包括了加筋铝板的应变场的有限元分析和光纤光栅传感监测系统的设计。最后,论述了该系统的模式识别算法研究,采用支持向量机和BP神经网络的算法对螺钉脱落的位置以及程度进行了判定,针对航空航天结构的特点,重点探讨了识别算法的泛化性能。本课题得到了国家自然科学基金资助项目(50278029、60772072)、航空科学基金资助项目(04A52002、20060952)和教育部新世纪优秀人才资助计划项目(NCET-04-0513)的资助。更多还原

【Abstract】 The joint of aviation aerospace structure is where the bolt joint invalidation easy happens, to prevent from disasters and losses incurred by structural damage, it is necessary to monitor structure effectively. The fiber Bragg grating sensors have lots of advantage, such as small size, light weight, anti-electromagnetism interference, wavelength division multiplexing, wavelength code and so on ,so they have a vast of applied foreground in the field of aviation aerospace structure health monitoring.On the background of Aeronautics and Astronautics structural health monitoring requirement, on a stiffened plate, aimed at the safety matter of structure joint invalidation, build a health monitoring system based on fiber Bragg grating sensor’s strain monitoring. In the thesis the discussion as following:The research background of this topic is introduced first, including summary of structure health monitoring and fiber Bragg grating, and domestic and international condition of structure health monitoring based on fiber Bragg grating. Secondly, working principle of fiber optic Bragg sensor is introduced. on the basis of the principle, the paper probed the technical points in the sensing applications of optic Bragg sensor. Thirdly, the joint invalidation monitoring system aimed on stiffened plate and the definition of joint invalidation modes are introduced, its main content consists of the finite element analysis about strain field on the plate and the monitoring system design. Fourthly, the pattern recognition algorithms in this system are discussed, positions and degrees of screwed off bolt are recognized. The research emphasis aimed to the feature of aviation aerospace structure is recognition algorithm’s generalization ability.更多还原