摘要
为满足低频勘探的要求,设计了一种基于膜片式悬臂梁结构的光纤光栅加速度计。对该传感器的结构进行了理论分析,建立有限元模型,对传感器的加速度传感特性进行了仿真分析。在振动台上对传感器的特性进行了测试。实验结果表明,该系统对低频加速度激励信号具有良好的响应,其谐振频率为48 Hz,频率响应范围为1~35 Hz,加速度计工作方向的灵敏度为452.6 pm/g,而其横向灵敏度仅为工作方向的灵敏度的2.16%,因此该加速度计具有较强的横向抗扰能力。
In the process of deep oil and gas exploration,low-frequency signal plays a key role.Therefore,accelerometers that can receive low-frequency signals are particularly important in low-frequency exploration.Compared with electric accelerometers,the Fiber Bragg Grating(FBG)accelerometer has the characteristics of anti-electromagnetic interference,small size,high-temperature resistance,and high resolution.Researchers have proposed various FBG vibration sensor structures,in which cantilever beam and circular diaphragm are two typical structures and have been widely studied.The early single cantilever fiber grating sensor has the characteristics of high sensitivity and weak lateral interference resistance.In contrast,the ordinary circular diaphragm structure has strong lateral interference resistance and low sensitivity.In this paper,we propose a low-frequency FBG accelerometer based on a diaphragm-type cantilever structure.It combines a plane circular diaphragm and an equal strength cantilever beam into one,which reduces the lateral interference and enhances the sensitivity coefficient.The diaphragm-type cantilever is made of a beryllium bronze sheet into a circular diaphragm.Then four symmetrically distributed equal strength cantilever beams are cut into the diaphragm.The four suspension beams jointly support a copper inertial mass block located in the diaphragm center.The edge of the diaphragm is fixed between the base and the gasket through screws.An FBG with a central wavelength of 1539.15 nm,a reflectivity of 90%and a grating area length of 10 mm is selected.The FBG is pasted at two points and fixed on the centerline of one cantilever of the diaphragm-type cantilever with 302 glue.The tail fiber at one end passes through the gap between the diaphragm-type cantilever and the gasket and is connected with the external optical demodulation equipment.According to the theoretical analysis,the optimal size of structural parameters of the diaphragm cantilever beam is obtained by MATLAB numerical simulation.According to t
作者
樊伟
冯德全
乔学光
FAN Wei;FENG Dequan;QIAO Xueguang(School of Physics,Northwest University,Xi′an 710127,China;Key Laboratory of Photoelectricity Gas-oil Logging and Detecting,Ministry of Education,Xi′an Shiyou University,Xi′an 710065,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2022年第10期173-182,共10页
Acta Photonica Sinica
基金
国家自然科学基金(Nos.61927812,61735014,62005214)。
关键词
光纤布拉格光栅
加速度计
膜片式悬臂
振动
横向抗干扰
Fiber Bragg grating
Accelerometer
Diaphragm-type cantilever
Vibration
Lateral anti-interference
