Nondestructive evaluation and mechanical characterization of a defect-embedded ceramic matrix composite laminate

A C/SiC composite panel with defects of known size and of familiar nature was manufactured successfully for nondestructive evaluation. A computed tomography (CT) system was used to detect embedded defects. The results show that CT imaging corresponds well with the designed defects. The defect-embedded composites undergo relatively greater loss in tensile strength and failure strain than the as-received samples, although their initial Young's moduli are almost identical. It is also observed that the embedded defects make a significant contribution toward the initiation and accumulation of the damage in the composites, which result eventually in the early failure of the composite.