Sagnac干涉型光纤振动传感器的设计与试验研究

【作者】 杨旭；

【导师】 李现国； 乔杰；

【作者基本信息】 天津工业大学 ， 电子信息（专业学位）， 2023， 硕士

【摘要】 振动信号的监测和分析对提高工程质量、维护设备运行安全具有十分重要的意义。光纤振动传感器具有体积小、重量轻、抗电磁干扰等特点,受到越来越多的关注。本文针对传统的电子类的振动传感器易受电磁干扰、不便于分布式测量等缺陷以及光纤振动传感器耐振动疲劳与高应力应变敏感难以兼容的问题,利用保偏光纤和光纤Sagnac干涉结构的特性,设计了一种Sagnac干涉型光纤振动传感器,主要工作如下:(1)研究了SPS(Single-mode-Polarization-maintaining-Single-mode,SPS)型光纤Sagnac干涉结构的应力敏感特性,仿真分析表明:随着应力的增加,SPS型光纤Sagnac干涉结构的干涉光谱向长波长方向偏移,应力变化灵敏度为0.144 nm/N。研究了基于Sagnac干涉结构和光纤环形激光器的振动传感系统传感特性,分析表明:检测到振动时,光纤Sagnac干涉光谱的滤波特性会改变激光器输出功率的强度,利用该特性可进行振动测量。(2)研究了Sagnac干涉型光纤振动传感器的设计与制作方法,设计并制作出一种单质点式的Sagnac干涉型光纤振动传感器,将质量块固定于保偏光纤,当传感器感应到振动时,质量块会随之晃动,能够增加保偏光纤受到的应力作用。通过理论分析和实验研究优化了传感器的结构参数,最终选择保偏光纤长度为10 cm、质量块质量为0.5 g。实验表明,该传感器与光纤环形激光器构成的传感系统的温度灵敏度为0.150 m W/℃、输出波长稳定在1550.13±0.01nm、无振动作用时输出功率稳定在298.1±0.3μW。(3)利用设计的Sagnac干涉型光纤振动传感器进行了轴承故障检测试验。试验结果表明:该光纤振动传感器对健康轴承和故障轴承测量分析结果与理论计算结果的相对误差均低于1.6%,验证了本文所设计的传感器的有效性和准确性以及耐振动疲劳的特点。该光纤振动传感器,能够用于工程结构、机械设备等领域的振动检测及故障监测,因其本征绝缘,尤其适用于煤矿、化工厂中要求使用防爆电气设备的旋转机械轴承故障检测,防止事故的发生,具有一定的应用价值。更多还原

【Abstract】 Vibration signals are monitored and analyzed,which is of great significance to improve engineering quality and maintain equipment operation safety.The optical fiber sensor has attracted more and more people’s attention because of its small size,light weight,anti-electromagnetic interference and other characteristics.To solve the problems that traditional electronic vibration sensors are susceptible to electromagnetic interference,inconvenient for distributed measurement,etc.,and optical fiber vibration sensors are difficult to be compatible with vibration fatigue resistance and high stress and strain sensitivity,the Sagnac interferometric fiber optic vibration sensor is designed based on the characteristics of polarization maintaining fiber(PMF)and fiber Sagnac interference structure in this thesis.The main work is as follows:(1)The stress sensitive characteristics of SPS(Single-mode-Polarizationmaintaining-Single-mode,SPS)fiber Sagnac interference structure are studied.The simulation analysis shows that with the increase of stress,the transmission spectrum shifts to the long wave direction,and the sensitivity of stress change is 0.144 nm/N.Then the sensing principle of the sensing system based on Sagnac interference structure and fiber ring laser is analyzed.the analysis shows that when vibration is detected,the filtering characteristic of fiber Sagnac interference spectrum will change the intensity of laser output power,which can be used to measure vibration.(2)The design and fabrication method of Sagnac interferometric fiber optic vibration sensor are studied.The single-substance point optical fiber vibration sensor is designed and manufactured.The mass block is fixed to the PMF.When the sensor senses the vibration,the mass will shake,which can increase the stress of the PMF.Through experimental and theoretical analysis,the structural parameters of the sensor are optimized,and 10 cm polarization-maintaining fiber and 0.5 g mass block are selected.The temperature sensitivity of the sensor system composed of the sensor and fiber ring laser is 0.150 m W/℃;The output wavelength is stable at 1550.13 ± 0.01 nm;When there is no vibration,the output power is stable at 298.1 ± 0.3μW.(3)The Sagnac interferometric fiber optic vibration sensor is used to test the bearing fault.The experimental results show that the relative error between the measurement and analysis results of normal bearing and fault bearing and the theoretical calculation results is less than 1.6%,the validity,accuracy and vibration fatigue resistance of the sensor designed in this thesis are verified.The optical fiber vibration sensor can be used for vibration detection and fault monitoring in engineering structures,mechanical equipment and other fields.Because of its intrinsic insulation,it is especially suitable for fault detection of rotating machinery bearings requiring explosion-proof electrical equipment in coal mines and chemical plants,prevent accidents from happening,and has certain application value.更多还原