Sensitivity Enhancement of FBG-Based Strain Sensor

• DOI: 10.3390/s18051607
• Publication Date: 2018-05-17T15:47:45Z
• Authors: Ruiya Li; Yiyang Chen; Yuegang Tan; Zude Zhou; Tianliang Li; Jian Mao
• Keywords: 550; Mechanical configurations; Strain sensitivity; fiber Bragg grating; strain; sensitivity enhancement; lever structure; 01 natural sciences; Natural frequencies; Article; Dynamics; Strain; Industrial environments; Sensitivity enhancements; Dynamic characteristics; Experimental test; Wide frequency range; 616; 0103 physical sciences; Fiber Bragg gratings; Theoretical modeling

A novel fiber Bragg grating (FBG)-based strain sensor with a high-sensitivity is presented in this paper. The proposed FBG-based strain sensor enhances sensitivity by pasting the FBG on a substrate with a lever structure. This typical mechanical configuration mechanically amplifies the strain of the FBG to enhance overall sensitivity. As this mechanical configuration has a high stiffness, the proposed sensor can achieve a high resonant frequency and a wide dynamic working range. The sensing principle is presented, and the corresponding theoretical model is derived and validated. Experimental results demonstrate that the developed FBG-based strain sensor achieves an enhanced strain sensitivity of 6.2 pm/με, which is consistent with the theoretical analysis result. The strain sensitivity of the developed sensor is 5.2 times of the strain sensitivity of a bare fiber Bragg grating strain sensor. The dynamic characteristics of this sensor are investigated through the finite element method (FEM) and experimental tests. The developed sensor exhibits an excellent strain-sensitivity-enhancing property in a wide frequency range. The proposed high-sensitivity FBG-based strain sensor can be used for small-amplitude micro-strain measurement in harsh industrial environments.