胶粘剂对表贴式聚酰亚胺光纤布拉格光栅应变传递的影响分析

Analysis of the Effect of Adhesives on Strain Transfer for Surface Bonded Polyimide Fiber Bragg Grating

光纤布拉格光栅传感器用于测量结构的应变时,需与被测基体相粘黏,使其与基体协调变形,故胶粘剂的选取对其测量结果有直接的影响。针对此问题,本文对表面粘贴式应变传递模型进行了改进,建立了更为合理的模型,并通过理论分析出了影响应变传递率的主要因素,得到了其传递率随胶体剪切模量的增大而增大的结论。通过控制变量法,用480胶、AB胶、401胶、环氧树脂、3311胶这五种不同胶粘剂,将聚酰亚胺光纤光栅粘贴于等强度梁表面进行对比实验,得到了相应的应变传递率,其结果与理论模型计算值相比误差在5%左右,为表面粘贴式光纤光栅测量应变的工程应用提供了重要的参考。

When the fiber Bragg grating sensor is used to measure the strain of a structure,it needs to be pasted and generates a coordination deformation with the measured substrate.Therefore,the selection of adhesives has a direct influence on the measurement results.To solve this problem,by improving surface bonded strain transfer model,a more reasonable model is built to analyze main factors affecting strain transfer coefficient.The theoretical analysis indicates that average strain transfer coefficient increases along with the increase of shear modulus of adhesive.By controlling variables,Polyimide FBGs are pasted on the surface of equal strength beam for a contrast experiment with Loctite 480 adhesive,AB adhesive,Loctite 401 adhesive,epoxy resin adhesive,and Loctite 3311 adhesive.The corresponding strain transfer coefficients have around 5%relative error with the calculation of the theoretical model.The results provide an important reference for engineering applications of surface bonded FBG strain measurement.