粘贴于薄板表面的光纤布拉格光栅应变传感器误差修正

考虑现有光纤布拉格光栅(FBG)传感器的应变传递理论均未考虑传感器对基体应变的影响,本文针对FBG传感器粘贴于薄板的情况研究了薄板的应变传递理论。由于光纤应变与薄板应变并不相等,故研究了光纤应变与薄板应变之间的关系以提高FBG传感器的测量精度。建立了粘贴于薄板表面的FBG传感器应变传递理论,分析了FBG传感器与薄板之间的相互作用;利用有限元法(FEM)和实验法验证了理论的正确性。最后,分析了薄板参数对应变传递率的影响。结果显示:FEM解与理论解的误差在4%以内,实验值和理论解误差在5%以内,应变传递率随着薄板厚度和弹性模量的增加而逐渐增大。该理论模型完全满足FBG传感器精度要求,对其实际应用具有一定的指导意义。

Error modification of FBG strain sensors bonded on plates

As the strain transfer theory of existing Fiber Bragg Grating(FBG) sensors does not take its effect on basic material strain into account, this paper researches the strain transfer theory for a FBG sensor bonded on a plate. The strain of an optical fiber is different from that of the plate, so the strain relationship between the optical fiber and the plate was studied to improve the measurement accuracy of FBG sensors. A theoretical model of strain transfer of FBG sensors bonded on the plate was presented, and the interaction between the FBG sensor and the plate was analyzed. Then the theoretical predictions were validated by Finite Element Method(FEM) and experimental data. Finally, the effect of the parameters of the plate on the strain transfer rate was analyzed. The results show that the error between the FEM and theoretical solution has controlled within 4% and that between the FEA and experimental data has controlled within 5%. Moreover, the strain transfer rate increases with the increases of both thickness and Young's modulus of the plate. It concludes that the theoretical model satisfies the accuracy requirement of the FBG sensors, and could provide a design reference for the FBG sensors.