Structural health-monitoring (SHM) systems can provide key information to improve marine hydrokinetic (MHK) device management: reduce operations & maintenance costs, mitigate failures, and improve capacity factor. While present systems include instrumentation to measure power output, few adequately monitor mechanical loads and structural response, which are equally important for determining device performance and integrity. Fiber-optic Bragg grating (FBG) sensors could prove to be a reliable and unobtrusive marine power measurement tool; however, externally adhered FBGs have not been extensively studied on submerged, dynamic structures.
Professors Erick Johnson and David Miller of Montana State University led the team in helping to characterize FBG sensors on a sectioned turbine foil. Dry results demonstrated very high correlation and response from the FBG sensors, up to coupon failure. The environmentally soaked samples and sensors were subject to many failure modes and verified the developer’s recommendation to not externally adhere the FBG strain sensors without additional mechanical and environmental protections.
Sandia’s Instrumentation and Materials & Manufacturing Reliability Program presented their initial work to explore SHM for MHK turbine foils at the 2014 Global Marine Renewable Energy Conference. This research was also accepted for publication in the Proceedings of the 2nd Marine Energy Technology Symposium. The research resulted from a cooperative research and development agreement between Ocean Renewable Power Company, Sandia, and the National Renewable Energy Laboratory. Micron Optics, Inc., (MOI) also helped guide sensor selection.