Monitoring Carbon Composite Structures With Optical Fiber Sensors

By Luna Technologies, a Division of Luna Innovations Incorporated

Fiber reinforced polymer composites are revolutionizing the design of large, high-performance structures in the aerospace, marine and power generation industries due to their advantages in areas such as corrosion resistance, specific strength and tailorability. The use of carbon fiber reinforced composites, the most common and lightest of the "non-exotic" composite materials, is now very widespread. The maiden flight of The Boeing Company's new 787 Dreamliner, the first commercial aircraft to use composites for most of its construction in December of 2009, is a stark example of just how far carbon fiber composite materials have come in the last 50 years: from hockey sticks, tennis rackets and R&D labs, to carrying us from here to there at 500 mph.

As modern design moves more towards the use of lighter and stronger materials like carbon composites, it must also move towards smarter materials. The relative inexperience with composite materials compared to their metallic counterparts often necessitates either overdesign of components or more frequent inspections and monitoring. Composite materials present a host of failure modes (cracks, disjoints, delaminations, etc.) that can be nearly catastrophic and very difficult to detect — a very bad combination. Photonics offers an elegant solution to this problem in the form of embedded fiber optic sensors for structural health monitoring (SHM).