Design and investigation of a sensitivity-enhanced fiber Bragg grating sensor for micro-strain measurement

摘要

The fiber Bragg grating (FBG) sensors are widely used in strain measurement. However, the current FBG sensors are not sensitive enough to monitor the micro-strain. In order to provide a feasible method to monitor the micro-strain of lithium-ion battery, a novel fiber Bragg grating (FBG) strain sensors with enhanced sensitivity was developed in this paper. A lever mechanism was adopted to enhance the sensor sensitivity and flexure hinges as well as serpentine springs were used in sensor structure. The sensor structure dimension was optimized through theoretical calculation and finite element analysis, and the optimized sensor was manufactured and tested. The results of calibration test show that in the measuring range of +/- 500 mu epsilon, the sensor has strain sensitivity of 11.49 pm/mu epsilon, good linearity and repeatability as well as tiny hysteresis error. The battery experimental results illustrate there is a same trend between strain and voltage of battery, and a good uniformity under three working modes of battery. This proposed FBG sensor will provide a solution for strain measurement of battery. (C) 2018 Published by Elsevier B.V.