建立表面粘贴布拉格光纤光栅(FBG)传感器、黏结层、被测物体三者间应变耦合传递的分离式模型,推导得出FBG测量应变与被测应变真值之间的修正关系。通过有限元模拟和实验,验证该理论模型的精确性,并在不同粘贴条件下讨论理论解的精确程度和适用性。结果表明:理论值与实验值稳合良好,误差普遍低于1.6%;应变感知率及精度与粘贴长度和涂层弹性模量呈正相关,与被测物体力学强度呈负相关;应变感知率对保护涂层、黏结层的几何特性不敏感,但其精度与两者呈负相关。研究成果对表面粘贴FBG应变测量、误差修正和传感器设计具有重要的参考意义。

A segregated model for strain transfer coupling in a surface-bonded fiber Bragg grating (FBG), adhesive, and measured object was established. In addition, the correction relationship between the FBG-measured and true strains on the surface was derived. The theoretical values were verified by finite element simulation and experimental results. Its accuracy and viability under various installation conditions were also discussed. The theoretical results match the experimental results well, with errors below 1.6%. The strain sensing coefficient and its accuracy are positively correlated with the adhesive length and elastic modulus of the protective recoating, while they are negatively correlated with the mechanical strength of the measured object. In addition, the accuracy of theoretical strain sensing coefficient is negatively correlated with geometrical features of protective recoating and adhesive, with an insensitive strain sensing coefficient. This study provides reference for strain measurements using a surface-bonded FBG, error correction, and design of relevant sensors.