Fatigue Crack Monitaring by Optical Fiber Embedded in Super Hybrid Material
Haga Osamu
Abstract:A super hybrid material plate built up from some aluminum alloy sheets and unidirectional FRP sheets is a kind of new composite material with many excellent mechanical properties. An optical fiber is an excellent sensor that has a wide range of application. It can be embedded into FRP structures so easily that it has become very important constituent material to create smart material and structures. The author succeeded in embedding the optical fiber into the super hybrid material plate. It was found out that several dB of right transmission loss increased when a fatigue crack tip crossed the optical fiber. After that, the transmission loss gradually increased with an increase of crack length. Therefore, to detect an arrival of a crack tip at the position of the embedding optical fiber and to monitor propagation of the crack tip after the arrival became possible by monitoring right transmission loss of the embedding optical fiber. Key Words:smart material, fatigue crack, optical fiber, optical transmission loss, super hybrid material