光纤Bragg光栅动态应变传感技术的研究

【作者】 舒睿俊；

【导师】 陈军；

【作者基本信息】 浙江大学 ， 光学工程， 2006， 硕士

【摘要】 光纤Bragg光栅传感器是利用Bragg波长对温度、应力的敏感特性而制成的一种新型的光纤传感器,除具有传统电类传感器的功能外,它还具有分布传感、抗电磁干扰、精度高、长期稳定性好等优点,在大型复合材料和混凝土的结构监测、智能材料的性能监测、电力工业、医药和化工等领域有着广阔的应用前景。 本文的主要内容包括: 介绍了光纤Bragg光栅的理论模型,并用耦合模理论分析了光纤Bragg光栅的光谱特性。系统研究了光纤光栅的温度、应变传感特性,并对现有的光纤光栅解调方案进行了分析和比较。 提出并建立了一套基于温控光纤Bragg光栅解调的光纤Bragg光栅动态高精度应变测量系统。传感光纤Bragg光栅的Bragg反射光受到动态应变调制,反射光其后入射到温控光纤Bragg光栅滤波器,传感系统通过测量温控光纤Bragg光栅的透射光强变化实现了动态应变解调。温控调节温控光纤Bragg光栅,使传感系统始终处于透射光强对应变变化最敏感的最佳状态。利用光纤Bragg光栅滤波器的大斜率特性,实现了高动态精度的动态应变传感。以简支梁的自由振动作为研究对象,在有效探测简支梁带宽为1～3200Hz的谐振频率范围内获得了高达6.7×10^-10。ε/Hz^1/2的动态应变测量精度。最后将光纤Bragg光栅动态应变传感系统和传统压电陶瓷传感系统的实验结果作了比较。 为了提高温控滤波光栅的调谐范围,提出了以应力传感光栅作滤波器的新方案。该方案利用与滤波应力传感器粘接的散热器材料的热膨胀系数较大的特性来达到提高滤波光栅调谐范围的目的。本文建立了这一实验系统,并进行了温度传感光栅和应力传感光栅调谐范围的测试,对测试结果进行了理论分析。实验结果表明应力传感器作为滤波光栅的调谐范围扩大了。更多还原

【Abstract】 Fiber Bragg grating （ FBG） sensor, which uses the property that the Bragg wavelength is sensitive to temperature and strain, is a new kind of fiber optic sensor. In addition to having the same functions as the traditional electric sensors, the FBG sensor also has some special characteristics such as distributed sensing, immune to electromagnetic interference, high precision and long-term stability. So it has widely applicable perspective in many fields such as the structure monitoring of large compound material and concrete, the performance monitoring of the intelligent materials, electrical power industry, medicine industry, chemical engineering et.The main contents are taken as follows:The fundamental theory of the fiber grating is introduced and the spectrum of FBG is analyzed by the coupling-mode theory. The temperature and strain- sensing characteristic of FBG is systematically investigated and the contrast and comparison of current demodulation methods is done.A high dynamic strain resolution FBG sensor system based on temperature controlled filter FBG is designed and established. The reflected light from sensor FBG is modulated by the dynamic strain, and is filtered by temperature controlled FBG. The sensor system measures the transmitted light power and demodulates the dynamic strain. The sensor system is ensured at the best measurement condition with the modulated temperature controlled FBG. And the high dynamic resolution is achieved with the high rate of filter slope of Temperature controlled FBG. The natural vibration of the free beam is researched by the sensor system. The resonant vibration frequency in bandwidth of 1-3200Hz is measured effectively, and the dynamic strainresolution reaches as high as 6.7×10^-10 ε/Hz^1/2. Finally, the experimentresults gained from the FBG sensor system and traditional PZT sensor are companioned.A new project which uses strain FBG sensor as filter FBG is designed to extend the variation range of filter FBG wavelength. The new system is established and the variation range of strain filter FBG and temperature filter FBG are gained. Finally, the results which are analyzed by the FBG sensor theory prove that using strain FBG sensor as filter FBG extend the variation range.更多还原