适用于桥梁振动监测的光纤加速度传感器研究

发布时间：2018-07-02 23:38

本文选题：光纤 + 加速度传感器　；参考：《石家庄铁道大学》2015年硕士论文

【摘要】：光纤传感测试技术由于具有抗电磁干扰能力强、测量精度高、稳定性好、能够实现远距离传输、便于复用成网等优点,已成为工程结构健康监测领域的重要发展方向。本文主要根据桥梁振动监测的实际需求,提出了一种基于45°F-P腔的光纤加速度传感器设计方案,并通过传感机理分析、结构优化设计、传感介质优选、封装工艺及性能考核试验等研究,研制出了能够满足桥梁振动监测要求的FP-45光纤加速度传感器。本文的主要研究工作和创新成果如下:第一,通过对桥梁结构振动特性分析、加速度信号感知途径及光纤F-P加速度传感器传感原理分析,提出了一种基于45°F-P腔的光纤加速度传感器设计方案。该设计方案借鉴已有光纤F-P加速度传感器结构设计的基础上,将45°镜面引入F-P腔中,有效解决了现有光纤加速度传感器的一阶共振频率与灵敏度的矛盾关系,在不增加质量块质量的前提下显著提高了传感器的灵敏度。第二,在对传感器的敏感单元(悬臂梁、基座、质量块、微调螺栓)和传感单元(F-P腔、内置45°镜面钢管、传感光路)结构优化设计的基础上,确定了传感器各组成部分的结构尺寸。该传感器外形尺寸为120 mm×80 mm×45mm,具有结构小巧、重量轻、现场安装简便的优点。第三,通过对光纤F-P加速度传感器的传感介质(主要包括光纤、反射膜和G-lens自聚焦透镜等)的优选试验,确定了最优的光纤芯径、反射膜尺寸和F-P成腔结构。当采用9/125μm的光纤及同芯经的G-lens和2×1耦合器,直径为1.5mm、反射率为90%的镀银膜和全反膜内置结构时,可显著增加光束耦合到光纤中的光束强度,并获得最好的F-P腔干涉条纹对比度,提高了光纤F-P加速度传感器的稳定性。第四,在对传感器的全反膜粘贴技术、G-lens透镜的封装技术和整体结构封装技术研究的基础上,确定了传感器的封装工艺,制作出了FP-45光纤加速度传感器,并对其进行了性能考核试验。试验结果表明:该传感器在测量量程、灵敏度、频率测试范围、频率响应特性和可靠性等方面均满足设计指标要求,适用于桥梁结构振动的长期监测。
[Abstract]:Optical fiber sensing testing technology has become an important development direction in the field of engineering structure health monitoring because of its strong ability of resisting electromagnetic interference, high measurement precision, good stability, long distance transmission and easy reuse to form a network. According to the actual needs of bridge vibration monitoring, a design scheme of fiber-optic acceleration sensor based on 45 掳F-P cavity is proposed in this paper. The FP-45 fiber optic accelerometer which can meet the requirements of bridge vibration monitoring has been developed through the research of packaging technology and performance test. The main research work and innovative achievements are as follows: first, through the analysis of bridge structure vibration characteristics, acceleration signal sensing approach and fiber F-P acceleration sensor principle analysis, A design scheme of fiber-optic acceleration sensor based on 45 掳F-P cavity is presented. Based on the structural design of fiber-optic F-P accelerometer, the 45 掳mirror surface is introduced into F-P cavity, which effectively solves the contradiction between the first order resonance frequency and sensitivity of the existing fiber-optic accelerometer. The sensitivity of the sensor is improved significantly without increasing the mass. Secondly, on the basis of optimizing the structure of the sensor sensitive elements (cantilever beam, base, mass block, fine-tuned bolt) and sensing unit (F-P cavity, built-in 45 掳mirror steel tube, sensing optical path), The structural dimensions of each component of the sensor are determined. The size of the sensor is 120mm 脳 80mm 脳 45mm, which has the advantages of small structure, light weight and easy installation. Thirdly, the optimal optical fiber core diameter, reflective film size and F-P cavity structure are determined by the optimal selection of the sensing medium (mainly optical fiber, reflective film and G-lens self-focusing lens) of the fiber F-P accelerometer. When we use 9 / 125 渭 m fiber, G-lens and 2 脳 1 coupler with 1.5mm diameter and 90% reflectivity, the intensity of the beam coupled to the fiber can be significantly increased, and the best contrast of the interference fringes of F-P cavity can be obtained. The stability of F-P accelerometer is improved. Fourthly, on the basis of the research on the packaging technology of the G-lens and the packaging technology of the whole structure of the sensor, the packaging technology of the sensor is determined, and the FP-45 fiber optic acceleration sensor is fabricated. The performance test was also carried out. The experimental results show that the sensor meets the design requirements in measuring range, sensitivity, range of frequency measurement, frequency response characteristics and reliability, and is suitable for long-term monitoring of bridge structure vibration.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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