Composite materials are becoming increasingly more valuable due to their high specific strength and stiffness. Currently, most components are operated for a number of service cycles and then replaced regardless of their actual condition. Embedded fiber Bragg gratings are under investigation for monitoring these components in real time and estimating their remaining life. This article presents research conducted on a novel technique for prediction of the remaining life of composites under fatigue loading using embedded fiber Bragg grating sensors. A prediction is made of the remaining life at every cycle based on data collected from the sensors and the previous loading history.

Glass ber reinforced composites (GFRC) are widely used in load bearing industrialapplications. Failure can occur in GFRC due to matrix cracking, ber breaking, crack coupling,delamination, or combined e ects of these failure mechanisms, and it is important to study thefailure mechanisms for qualitative inspection of the material during its operation. In this paper,GFRC is manufactured using resin transfer molding, and ber Bragg grating is embeddedin the composite during the manufacturing step. A strain gage is surface mounted on thecomposite, to correlate the FBG measurement data. GFRC is subjected to continuous tension-compression load cycles at 1Hz using MTS 322 test-frame servo-hydraulic test machine. TheFBG is characterized in this loading regime, and its strain sensitivity calculated. The cyclicloading induces local buckling the composite. It is observed that the buckling does not leadto immediate failure. However, the initial local buckling is transient in nature and surfaces atcompression stage of the loading cycle. Continuous loading cycles, leads to permanent bucklingin the composite leading to complete failure of the composite, and is observed in real-time usingFBG.