Fatigue damage monitoring in polymeric composites using multiple fiber bragg gratings

Cyclic loading during service may induce sub-surface defects in polymeric composite materials. These insidious defects may grow and eventually lead to catastrophic failures. The current work aims at exploring the possibility of using embedded fiber Bragg grating to monitor damage evolution. Fatigue damage evolution in Graphite/Epoxy coupons having a [−45/90/+45/0]2s lay-up sequence with a central circular hole subjected to cyclic loading is evaluated. This study suggested that the embedded fiber bragg gratings have good potentials to detect the appearance of damage. It is hoped that this methodology can be further developed as an online condition monitoring technique for safety-critical structures, thereby improving the safety and reliability of composite structures.