Fibre-Optic Monitoring System Embedded into Composites

Nanoelectronics research centre imec, Ghent University, and their partners in the European FP7 project Smartfiber have demo’d the world’s first miniaturised fibre-optic sensor system than can be fully embedded in a composite material.

The sensor system was assembled on an electronic board designed by Xenics, the optical subsystem consists of a silicon photonics integrated circuit developed by imec and photodiodes and read-out ICs provided by Xenics.

Fraunhofer IIS was responsible for the wireless interface which provides power to the embedded system whilst at the same time reads out the data at high speed. After connecting the system to an optical fibre sensor, it was then cast in an epoxy shape designed to minimise the impact on the composite material. Finally, together with the attached fibre sensor chain it was embedded in the blade of a tidal turbine by Airborne.

The new sensors are compact, light weight and immune to electromagnetic interferences, whilst being highly resistant to corrosion and able to work in high temperatures. The smart system will enable for the first time fully embedded structural health monitoring of composites used in structural parts such as wind turbine blades, satellites, airplanes, civil constructions, oil and gas wells, boat hulls, propellers.

Special automated techniques were developed to embed the sensors in the composite. This, together with the use of a silicon-based micro fabrication processes lowers the cost of embedded strain sensors substantially.