Accurate Measurement of Large Strain under High-temperature Environment Based on Fiber Bragg Grating

Strain measurement technology under high-temperature environment has been a hot and difficult research issue in the field of measurement. On the one hand, conventional resistive strain gauges are susceptible to electromagnetic interference at high temperature. And on the other hand, common fiber sensors will be invalid under high-temperature environment, and may fall off under large strain conditions. In this paper, a precision measurement scheme that combining plasma surface treatment and metal oxide adhesive based on fiber Bragg grating (FBG) of large strain under high temperature environment is proposed, where three types of protection for the grating area of a FBG sensor were established, and a new plasma surface treatment method is theoretical analyzed and experimental studied. Suitable adhesive is also carefully selected according to the characteristics of the sample to be measured. After optimizing the mechanical transfer effect with the proposed method, effective coupling between the surface of the sample to be measured and the fiber grating sensor is realized, and large strain measurement up to 1200με under 1000°C environment is experimentally achieved.