NONDESTRUCTIVE EVALUATION AND CHARACTERIZATION OF MICROFIBERS MODIFIED TEXTILE CARBON-PHENOLIC AND CARBON-CARBON COMPOSITES

Short carbon microfibers have been added to carbon-phenolic fabric com posites of plain, eight-harness satin (8HS) and stretch broken 8HS wea ve architectures. The resulting composites have been studied for their interlaminar mechanical properties as well as process related materia l evolution mechanisms that result in carbon-carbon (C-C) composites. Dry coupling ultrasonic A-scan velocity measurements, immersion type u ltrasonic C-scan technique, acousto-ultrasonic (AU) stress wave factor measurements and vibration damping ratio based nondestructive evaluat ion-characterization (NDE-C) test parameters were studied in relation to the carbon-phenolic and C-C composites. Interlaminar shear strength (ILSS) tests were conducted along with acoustic emission (AE) monitor ing. From the various NDE techniques accompanied by mechanical tests a nd processing stages, the dependence of fabric weave architectures wit h short microfibers has been established.