Spectral Analysis of Fiber Bragg Grating Sensor on Glass Fiber Reinforced Polymer

An effective technique must be utilized to monitor composites' health as its application in engineering constructions grows to avoid sudden failure as it degrades. In line with that, this study analyses the progress of fatigue strain on GFRP specimens during fatigue tests using the FBG wavelength shifts parameter. Its purpose was to monitor the FBG wavelength shifts during three stages of fatigue test. Fatigue test specimens were firstly fabricated using the hand layup technique. Tensile and fatigue tests were conducted on the fabricated GFRP specimens. The FBG wavelength spectrums were acquired using the FBG sensor during the fatigue test of each specimen at 40% stress amplitudes. Spectral analysis was then carried out to characterize the FBG spectrum as the fatigue failure progresses. As a result, the FBG wavelength shifted each time the stress amplitudes were applied to the GFRP fatigue test specimen. The GFRP specimen that was applied with 40% of the ultimate stress was presented. These shifts and changes were observed at the early, middle, and final stages of the fatigue test. Wavelength shifts were not obvious in the early stage but abrupt in the middle and final stage of fatigue test of the GFRP specimen.