Monitoring of multi-material structures for offshore applications with fiber optic sensors

The development of renewable energies is a fundamental need to cover the ambitious energy targets demanded by industry and the European Union in the coming years. Wind energy is one of the most promising sources of renewable energy today. But, in the case of offshore wind energy, it has certain limitations due to its relative youth and associated costs, especially in the maintenance, operation and repair operations. Within the project, that includes this work, has been developed a new multi-material component with high structural requirements for the offshore wind sector. A combination of steel and fiberglass (GF) composite material, manufactured by filament winding, with a protection paint from to biofouling and corrosion, will be developed and validated in a real conditions test in the experimental zone of INEGA (A Coruña, Spain), by a demonstrator to scale 1:5. For real-time monitoring of the multi-material structure, a monitoring system based on fiber optics sensors type Bragg Grating (FBG) has been developed and integrated in this multi-material structure. This monitoring system includes sensors of corrosion, temperature and strain. This paper shows the development and characterization of these sensors at the laboratory level against mechanical, thermal tests and a durability study in a marine environment. In addition, it describes the integration of the monitoring system in the demonstrator and its response during the validation phase.