Abstract A method for detecting structural flaws in filamentary reinforced composite structures is described. A plurality of optical lead glass or other suitable ''''light-piping'''' filaments are positioned within the structure during manufacture, such that the ends of the filaments are accessible when the structure is complete. A failure, or flaw, within the structure traversed by the lead glass filaments will sever the lead glass filaments. A severed glass filament will not ''''pipe'''' light, as it did before the discontinuity occurred. This change can be detected during an inspection procedure which consists of applying a light source to one end of the filament, and monitoring the light output at the other end of the filament. The position of the lead glass filament within the structure can be ascertained by radiographic inspection. The modulus of elasticity of the optical filament is matched with the elastic modulus of the structural filaments to optimize the detection of flaws.
A method of detecting structural flaws in a composite filamentary reinforced plastic structure comprising the steps of: a. Placing optical filaments, within the filamentary reinforced structure in such a manner that the ends of the optical fibers are accessible as inspection points and light source points; b. Subjecting the structure to loads; c. Removing the loads; d. Applying a light source to the light source end of the optical fibers; e. Monitoring the light output at the inspection end of the optical fibers being illuminated; f. Identifying discontinuities of the optical filament, by noting which filaments do not conduct light from the light source point to the inspection point.
Claim 2
Independent Claim
109 words
A method of detecting structural flaws in a composite filamentary reinforced plastic structure comprising the steps of: a. Placing optical filaments, within the filamentary reinforced structure in such a manner that the ends of the optical fibers are accessible as inspection points and light source points; b. Subjecting the structure to loads; c. Removing the loads; d. Applying a light source to the light source end of the optical fibers; e. Monitoring the light output at the inspection end of the optical fibers being illuminated; f. Identifying discontinuities of the optical filament, by noting which filaments do not conduct light from the light source point to the inspection point.
Claim 3
Dependent Claim
36 words
The method according to claim 1 comprising the additional step after step (f) of examining the overall filamentary reinforced composite structure with radiographic equipment to isolate the site of discontinuity of the severed lead glass fiber.
Claim 4
Dependent Claim
29 words
The method according to claim 1 comprising the additional step before step (a) of selecting fibers with a modulus of elasticity similar to that of the basic composite structure.