A theoretical strain transfer model analysis of the substrate-bonded FBG sensor considering the influence of groove

Abstract This study introduces a novel theoretical model for substrate-bonded FBG sensors aimed at eliminating strain transfer error by considering the influence of the groove. The model comprises two main components: the encapsulated FBG and the substrate, with an assumptive plane acting as the connecting link. The strain transfer relationship between the substrate-bonded FBG sensor and the host material is deduced. Validation of the theoretical predictions is achieved through finite element numerical analysis and experimental validation, demonstrating good agreement between the calculated values and both numerical simulation values and experimental observations. Additionally, parametric analysis is conducted to explore the impact of material and geometric features on the strain transfer coefficient and the average strain transfer coefficient.