ULTRASONIC CHARACTERIZATION OF CARBON/CARBON COMPOSITES BASED ON A PEAK-DELAY MEASUREMENT METHOD

In this work, a C/C composite material was nondestructively characterized and a technique was developed to measure ultrasonic velocity in C/C composites using automated data acquisition software. We have proposed a peak-delay measurement method based on the pulse overlap measurement method. Also through transmission mode was performed to compare ultrasonic velocity with the above peak-delay measurement method in an immersion tank. The variation of ultrasonic velocity was measured and found to be consistent with those in a large C/C composite. These results were compared with that obtained by dry-coupling ultrasonics. For mapping out the material property inhomogeneity, through-transmission scans were used based on both amplitude and time-of-flight of the ultrasonic pulse. A peak-delay measurement method well corresponded to the ultrasonic velocities of the pulse overlap method and through-transmission mode and C-scan image signal.