FBG Strain Measurement of the Aircraft High Temperature Structure

There are two important problems in applications of the Fiber Bragg Grating (FBG) strain sensor in Aircraft High Temperature Structure Test. One is its reliable installation in high temperature, and the other is the cross sensitivity of strain and temperature. In order to solve these problems, the installation technology research, and the temperature-strain response research of FBG sensor were carried out in high temperature environment. The result shows that FBG sensor can be installed on the sample reliably by using the laser welding process and the plasma spraying process. By using infrared radiation equipment and trapezium cantilever, the temperature responsive coefficient from 30 ℃ to 1000 ℃ and the strain responsive coefficient from 0 με to 550 με of the FBG sensor were obtained. Meanwhile, the FBG measurement value was calibrated from 20 με to 6000 με by bone shape sample and regular strain gauge. Finally, the FBG sensor was applicated in high temperature structure test, and the steady strain value was obtained at 700 ℃.