Liu Fufei, Dai Yutang, Karanja Joseph Muna, Yang Minghong
National Engineering Laboratory for Fiber Optic Sensing Technology, Wuhan University of Technology, Luoshi Road 122, 430070 Wuhan, China.
Physics Department, Pwani University, P.O. Box 195-80108 Kilifi, Kenya.
Sensors (Basel). 2017 Jan 22;17(1):206. doi: 10.3390/s17010206.
To meet the requirements for low-frequency vibration monitoring, a new type of FBG (fiber Bragg grating) accelerometer with a bended spring plate is proposed. Two symmetrical bended spring plates are used as elastic elements, which drive the FBG to produce axial strains equal in magnitude but opposite in direction when exciting vibrations exist, leading to doubling the wavelength shift of the FBG. The mechanics model and a numerical method are presented in this paper, with which the influence of the structural parameters on the sensitivity and the eigenfrequency are discussed. The test results show that the sensitivity of the accelerometer is more than 1000 pm/g when the frequency is within the 0.7-20 Hz range.
为满足低频振动监测的要求，提出了一种新型的带有弯曲弹簧片的光纤布拉格光栅（FBG）加速度计。两个对称的弯曲弹簧片用作弹性元件，当存在激励振动时，它们驱动FBG产生大小相等但方向相反的轴向应变，从而使FBG的波长偏移加倍。本文给出了力学模型和数值方法，并讨论了结构参数对灵敏度和固有频率的影响。测试结果表明，当频率在0.7 - 20 Hz范围内时，加速度计的灵敏度超过1000 pm/g。
