Strain transfer efficiency model and finite element simulation experiment for end-bonded substrate-type FBG sensors

FBG sensors are widely used in damage monitoring of wind turbine blades. Due to the adhesive layer, strain transfer loss occurs when blade strain is transmitted to the fiber Bragg grating. This paper proposes a strain transfer efficiency model for the end-bonded method of substrate-type FBG sensors, and conducts numerical analysis on the elastic modulus, Poisson's ratio, and thickness of the bonding adhesive layer, as well as the gauge length of the FBG sensors. Finally, finite element simulation is used to verify the accuracy of the derivation. The results of numerical analysis and finite element simulation show that the proposed model can describe the law of strain transfer in the end-bonded structure of substrate-type FBG sensors and reveal the influence mechanism of each key parameter on the transfer efficiency.