Research on Strain Distribution Detection Method of Freeform Surface Based on FBG Array

In order to obtain the strain distribution of the free-form surface to be tested and reduce the difficulty of assembling large-scale curved structures, a free-form surface strain distribution detection method based on FBG array was designed. The system consists of a laser, a coupler, a demodulator, and an FBG array. The strain distribution and displacement offset of the test specimen under five different force conditions are simulated and analyzed. The simulation results show that the strain distribution is related to the position, size and surface structure of the applied force. The experiment was tested on a 3 mm aluminum plate and compared to the simulation data. l. The experimental results show that the maximum strain is 24.7µϵ and the minimum strain is 2.8µϵ. The difference in strain at the same curvature position is significant. It verifies the feasibility of solving the displacement field distribution by the strain field distribution. (paper)