Ultrasonic Inspection of Carbon/ Phenolic Composites Using a Peak-Delay Measurement Method
Carbon/phenolic composite (CPC) materials are unique which consist of carbon fibers embedded in a carbon matrix. The CPCs are originally developed for aerospace applications and its low density, high thermal conductivity and excellent mechanical properties at elevated temperatures make it an ideal material for aircraft brake disks. The properties of the CPC are dependent on the manufacturing methods used for production and fiber arrangement. It is desirable to perform nondestructive evaluation to assess material properties and part homogeneity in order to ensure product quality and structural integrity of CPC brake disks. In this work, a CPC material was nondestructively characterized and a technique was developed to measure ultrasonic velocity in C/P composites using automated data acquisition software. Also a motorized system was adopted to measure ultrasonic velocity on the point of CPC materials under the same coupling conditions. Manual results were compared with those obtained by the motorized system with using drycoupling ultrasonics and through transmission method in immersion. A peak-delay measurement method well corresponded to ultrasonic velocities of the pulse overlap method and throughtransmission mode and C-scan image signal based on peak-to-peak amplitude.
Seung-Seok Lee, Joon Hyun Lee, Ik Keun Park, Sung-Jin Song, Man Yong Choi
I. Y. Yang et al., "Ultrasonic Inspection of Carbon/ Phenolic Composites Using a Peak-Delay Measurement Method", Key Engineering Materials, Vols. 321-323, pp. 889-892, 2006