Comparison of ultrasonic flaw detection analysis for spherical composite test specimens using two data acquisition techniques

Technical Report · Thu Nov 19 00:00:00 EST 1987

OSTI ID:5610706

Brosey, W D; Cantrell, J L

A study of nondestructive evaluation techniques on spherical filament wound Kevlar-epoxy test specimens has been performed at the Oak Ridge Y-12 Plant. Epoxy wetted fibers were wound on an aluminum mandrel to form the specimens. Two of the ultrasonic methods used to evaluate the specimens have been compared to determine their flaw detection capability. The first ultrasonic technique used a gated peak detector to isolate the highest signal amplitude within a preset region of the waveform. The second method consisted of digitizing the entire waveform for computerized post acquisition analysis. Seventy composite spheres containing one of seven defect conditions were inspected using both ultrasonic techniques. The defect conditions were: a no defect standard, Teflon shim simulated delaminations, low epoxy matrix, alternate winding pattern, macrosphere simulated voids, fiber tension variation, and alternate fiber. Teflon shim simulated delaminations proved to be the most detectable of the flaw types using ultrasonic analysis. Therefore, a specimen containing Teflon shim delaminations was used to demonstrate the differences in flaw finding capabilities of the two ultrasonic detection methods. The shims were placed at two depths within the composite, at half thickness and near the back surface, aluminum-mandrel interface. Data acquired using each of the techniques were displayed to obtain a map of the delaminated areas. The delamination maps were used to determine how successful each method was at locating flawed regions.

• Research Organization: Oak Ridge Y-12 Plant, TN (USA)
• DOE Contract Number: AC05-84OS21400
• OSTI ID: 5610706
• Report Number(s): Y/DW-751; ON: DE88005002
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

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