Chapter 37. Ultrasonic Nondestructive Evaluation of Carbon/Cafwon Brake Disks

  1. Don Bray
  1. Kwang-Hee Im1,
  2. David K. Hsu1 and
  3. Hyunjo Jeong2

Published Online: 23 MAR 2010

DOI: 10.1002/9780470294499.ch37

22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 19, Issue 4

22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 19, Issue 4

How to Cite

Im, K.-H., Hsu, D. K. and Jeong, H. (1998) Ultrasonic Nondestructive Evaluation of Carbon/Cafwon Brake Disks, in 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 19, Issue 4 (ed D. Bray), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294499.ch37

Author Information

  1. 1

    Center for NDE Iowa State University 1915 Scholl Road, Ames, IA 50011

  2. 2

    School of Mechanical Engineering Pusan National University San 30, Changjon-Dong, Kumjeong-Gu, Pusan, 609–735, Korea

Publication History

  1. Published Online: 23 MAR 2010
  2. Published Print: 1 JAN 1998

ISBN Information

Print ISBN: 9780470375594

Online ISBN: 9780470294499

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Keywords:

  • interpretation;
  • biological effects;
  • volatilized;
  • contaminated;
  • ingestion

Summary

The manufacturing of carbodcarbon brake disks requires complicated and costly processes; it is therefore desirable to perform nondestructive evaluation (NDE) to assess material properties and part homogeneity. In this work several ultrasonic techniques were applied to carbodcarbon brake disks for the evaluation of spatial variations in material properties that are attributable to the manufacturing process. In a carbon/carbon brake disk manufactured by a combination of pitch impregnation and vapor infiltration methods, the spatial variation of ultrasonic velocity was measured and found to be consistent with the nonuniform densifcation behavior in the manufacturing process. Low frequency (e.g., 1–5 MHz) through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. These results were compared with that obtained by dry-coupling ultrasonics. A good correlation was found between ultrasonic velocity and material density on a set of small blocks cut out of the disk. Pulse-echo C-scans at higher frequency (10–25 MHz) was used to image near-surface material property anomalies associated with certain steps in the manufacturing process, such as the placement of spacers between disks during the final chemical vapor mfiltration.