Eddy Current Inspection of Graphite-Epoxy Solid Rocket Motor Canisters
Filament wound graphite/epoxy cylinders are used in a number of applications because of their favorable strength-to-weight ratio. Eddy current techniques are receiving more attention for composite inspection because eddy currents detect broken fibers but not delaminations. Therefore, eddy current inspection of this material would be desirable in its own right and as an adjunct to ultrasonic inspection which detects delaminations, but not broken fibers. However, filament wound graphite/epoxy is difficult to inspect because of its large and anisotropie electrical resistivity. This paper presents a technique for eddy current NDI of filament wound graphite/epoxy which uses currents flowing in the low-resistivity circumferential direction. This method eliminates several objections to conventional eddy current inspection of this material.
KeywordsBreak Fiber Pickup Coil Ultrasonic Inspection Filament Wound Anisotropic Resistivity
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