Reliability assessment of measurement accuracy for FBG sensors used in structural tests of the wind turbine blades based on strain transfer laws. (May 2020) - Liu, Zheng
Highlights: This paper established an accuracy reliability calculation model based on strain transfer efficiency for FBG sensors packaged by composites. This paper analyzed the influences of material properties and geometric parameters of the adhesive layer on the performance of FBG sensors based on finite element analysis (FEA) method, and we find that the bond length L and the bond thickness h of the adhesive layer have greater influence on the strain transfer efficiency and the accuracy reliability of the FBG sensors. The strain transfer efficiency and the accuracy reliability of the FBG sensors under static load are a little higher than the ones under suddenly applied loads. The instantaneous strain transfer efficiency decreases over time when the FBG sensors are subjected to suddenly applied loads; the frequency of alternating load influences a lot on the performance of the FBG sensors, and the higher the frequency, the higher the strain transfer efficiency and the accuracy reliability are. Abstract: FBG sensors are often packaged within composites before they are pasted on the blade surface, and many studies have shown that the materials, fatigue properties, geometric parameters, etc. of intermediate layer have influences on the measuring accuracy of the FBG sensors. Thus, this paper established an reliability calculation model based on strain transfer efficiency for the measuring accuracy of FBG sensors packaged by composites, analyzed the influences of material properties and geometric parameters of the adhesive layer on the performance of FBG sensors based on finite element analysis (FEA) method, and then compared the differences of strain transfer efficiency and reliability of the FBG sensors under different load conditions. The results show that the bond length and the bond thickness of the adhesive layer have greater influences on the performance of the FBG sensors compared with other parameters, both the strain transfer efficiency and the reliability of the FBG sensors will reduce over time under suddenly applied load and increase with increasing frequency of the alternating load.