| 摘要 |
PURPOSE:To detect internal damage as quickly as possible, by checking breakage of optical fibers buried in a fiber-reinforced composite material or adhering to the surface thereof depending on the presence of propagation of light. CONSTITUTION:In the basic structure of a carbon fiber-reinforced resin 1, numer ous carbon fibers 3 are oriented in one direction and prepregs 2A-2F half- hardened by being impregnated with an epoxy resin 4 are laminated alternately in such a direction that the carbon fibers 3 direct differently to form a prepreg 2 and cured. Optical fibers 5 are buried in the prepreg 2A at proper intervals along the carbon fibers 3; one end of a portion extruded at both ends thereof is gathered to a light irradiation end 7 set in an airframe, and the other end is reduced to be fixed at a proper position easy to observe. When light from a light source 6 irradiates the light irradiation end 7, light passing through the separate optical fibers 5 creates bright spots at the other end thereof. When a local fracture of the carbon fibers 3 is caused at a broken part 8 of a wing under an excessive load, the optical fiber 5 breaks at the same portion and the bright spot disappears dark.
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