PENETRATION OF CARBON-FABRIC REINFORCED COMPOSITES BY EDGE CRACKS DURING THERMAL AGING

The purpose of this work was to characterize the thermal degradation o f carbon fabric reinforced PMR-15 polyimide composites by investigatin g the formation of edge cracks in composites of different geometric de signs. A simple, innovative water immersion technique was developed to augment the standard metallographic and radiographic examinations tha t are normally performed in evaluating oxidative exposure effects on c omposite materials. This technique was used to quantify the amount and distribution of crack volume generated by the aging process. The crac k volume was assumed to indicate the relative magnitude of crack surfa ce area that was created. The results of this study clarified the rela tionships between crack formation and growth and the thermal and oxida tive degradation of carbon fabric reinforced composites.