Next-generation marine vessels are adopting composite materials for substructural elements, and due to a lack of knowledge about these materials’ failure modes, the need for monitoring them is substantial. A solution is to implement a structural health monitoring (SHM) system by embedding Fiber Bragg Gratings (FBG) during fabrication of the composite structure. The choice of FBGs is motivated by their ability to withstand harsh environments, immunity to electromagnetic interference, small bonding footprint, and the ability for easy in-line multiplexing.

The experimental test setup included FBG embedded composite plates that were impacted by a 400lb hammer until various known failure modes were achieved and then subjected to a vibration tests. After the time series data was been collected, signal processing techniques such as power spectral density and auto-regressive modeling were used to help differentiate the various levels of damage.

In future work, full scale submarine models would be instrumented with the SHM system and then subjected to blast testing using real explosives. Also, it will be important to examine the Bayes Risk formulation to find the most optimal performance detector, where the cost associated with making both incorrect and correct detections are included in the optimization.