An experimental investigation on reliability of CFRP packaged FBG sensors with different bonding methods

The paper made an experimental investigation on reliability of carbon fiber reinforced polymer (CFRP) packaged fiber Bragg grating (FBG) sensors which would be used in full-scale fatigue test of wind turbine blades (WTBs). Before the CFRP packaged FBG sensors are used to measure the strain of the WTBs, they are bonded on the surfaces of the WTBs with adhesives, thus, the bonding parameters, such as adhesive types, adhesive thicknesses will have influences on the strain transfer characteristics of FBG sensors. The measurement accuracy of CFRP packaged FBG sensors under static load are studied, while the measurement accuracy of CFRP packaged FBG sensors under alternating load is unknown. Moreover, the influences of the adhesive types and thicknesses on the measurement accuracy of CFRP packaged FBG sensors are little studied. Thus, this paper tries to make a study on the influences of adhesives types and thicknesses on the reliability of CFRP packaged FBG sensors by testing methods. The results show that the strain transfer efficiency of CFRP packaged FBG sensors increases with the decreasing of adhesive thickness, and the Loctite 480 has a better anti-fatigue ability compared with other adhesives.