由于用表面粘贴式光纤布拉格光栅(FBG)传感器测量应变时会影响基体的应变分布, 本文研究了光纤应变与基体应变之间的关系。针对该类传感器建立了基体与光纤之间的应变传递函数用以修正测量应变, 然后研究了FBG传感器与基体之间的相互作用。最后, 利用有限元分析(FEA)和实际实验对提出的理论进行了验证。结果显示: 光纤应变的FEA解与理论解的误差在5%以内, 实验解与理论解的误差在8%以内, 结果表明该理论完全满足表面粘贴式FBG传感器的精度要求。另外, 分析了黏结层和基体对应变传递的影响, 结果显示: 平均应变传递率和应变传递率随着基体弹性模量的增加而增加, 但它们随着黏结层顶端厚度和底端厚度的增加而逐渐减小。

When a surface-bonded Fiber Bragg Grating (FBG) sensor is used to measure the strain of a host material, it will effect the strain distribution of the host material. Therefore, this paper explores the relationship between optical fiber strain and host material strain. A theoretical model of strain transfer of the host material to the optical fiber was presented to modify the measured strain, and the interaction between FBG sensor and host material was considered. Finally, the theoretical predictions proposed in this paper were verified by Finite Element Analysis(FEA) and practical experiments. The results show that the error between FEA and theoretical solution is controlled within 5%, and that between theoretical solution and experimental data is controlled within 8%. These mean that the strain transfer mode satisfies the accuracy requirement of surface-bonded FBG sensors. Moreover, the effects of geometrical and material parameters on the average strain transfer rate and the strain transfer rate were analyzed. The obtained results indicate that the average strain transfer rate and the strain transfer rate increase with the Young's modulus of the host material. However, they decrease with increasing the top thickness and bottom thickness of an adhesive layer.