CALSENS, working within the framework of REFEST project, has achieved the Milestone 5 through the successful integration of multiple optical fibre sensors inside different composite materials. Proving that the behaviour and structural health of the fibre and the sensor elements are not affected by the composite fabrication process, and that even different temperature and strain measurements can be performed during the fabrication process.
As a part of Milestone 5, CALSENS has manufactured multiple FBG in conventional fibre (both with femtosecond and UV laser techniques) both in a single sensor configuration and in arrays of several FBGs. With the collaboration of AIMPLAS, CALSENS has integrated these fibres in multiple composite panels and pieces of different dimensions and materials (carbon fibre, glass fibre, with different resins, etc) and in different configurations, with several fibres in each panel (up to 25 FBG sensors integrated in the same composite piece). Additional protections for the fibre have been developed and validated for the entry points into the composites, ensuring a protect and robust transition in the most critical point of the new structures.
The different materials tested in the composites are similar to the ones that will be employed fin hull appendage construction for fishing vessels. The embedded sensors have been employed to measure strain, waterflow, temperature changes, water-level/buoyancy and deformation/shape change of the panel in realistic lab conditions, providing a stable sensing signal under the expected mechanical and thermal stress.
The successful integration achieved in the milestone proves the viability of the monitoring technology for further uses in the REFEST consortium and will allow for the deployment and use of the fibre FBG sensors integrated in future tasks, including the installation and monitorization in real vessels for the latter stages of the project.