Feasibility Study of Fiber Bragg Grating Sensor for Strain Measurement in Flight Test

Abstract

In order to promote the application of fiber Bragg grating (FBG) sensor in strain measurement of flight test field, ground verification tests were carried out, and the effects of the packaging structure and the bonding technology of the sensor were analyzed. FBG has the advantages of small size and light weight in flight test applications, but the optical fiber is easily damaged, so it is necessary to use a stainless steel substrate to encapsulate the optical fiber and then use AB glue to bond to the test substrate. In this paper, FBG and resistance strain gages are compared to verify the feasibility of strain measurement. The results show that the response trend of the FBG sensor is consistent with the resistance strain gauge, but there is a large strain loss in the bonding layer of the FBG after packaging. Further establish a strain transfer model for simulation analysis, and quantitatively calculate measurement error. It is proposed that under the premise of meeting the feasibility of flight test process, the thickness of the cement layer should be small enough and the elastic modulus should be large enough, which can effectively improve the accuracy of FBG strain measurement.