ULTRASONIC TECHNIQUES AND STANDARDS FOR TESTING FILAMENT-WOUND STRUCTURES.
Rept. for 1 May 63-27 Mar 64,
DOUGLAS AIRCRAFT CO INC SANTA MONICA CALIF
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Optimum techniques and standards were developed for ultrasonic testing of filament-wound reinforced resin-glass structures. Filament-wound reference test blocks, 0.1 in. to 2.0 in. thick in 14 in. increments, were fabricated. Blocks were prepared of optimum quality and with simulated defects. One set of optimum blocks was adhesively bonded to rubber liners that were 0.080 in. to 3.0 in. thick. Ultrasonic tests were performed to measure acoustic properties and to establish optimum test conditions to detect such defects as delaminations, unbond, porosity, and resin content. Ultrasonic tests were performed by immersed through-transmission methods and by both immersed and contact pulse-echo methods. It was found that the optimum method of defect detection was through-transmission testing with facsimile recording. A combination of throughtransmission methods and pulse-echo methods was used in evaluating defects detected by through-transmission testing. Pressure vessels obtained from several manufacturers of filament-wound structures were ultrasonically tested by techniques and standards developed in this program. Discontinuities in these chambers were reliably detected. Author