Chapter 45. Fatigue and Flexural Response of Advanced Carbon-Carbon Composites at Room and Elevated Temperatures
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1992 The American Ceramic Society
Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8
How to Cite
Mahfuz, H., Das, P. S., Jeelani, S., Baker, D. M. and Johnson, S. A. (1994) Fatigue and Flexural Response of Advanced Carbon-Carbon Composites at Room and Elevated Temperatures, in Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313954.ch45
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1994
Print ISBN: 9780470375174
Online ISBN: 9780470313954
Response of quasiisotropic laminates of Sic coated Carbon-Carbon composites under flexural load were studied. Mission cycled as well as virgin specimens were tested to compare the thermal and pressure cycling effects. Test temperatures were varied from room to 1371OC (2500OF) in air, to investigate the load deflection behavior of the material and the thermal stability of the oxidation protection system under such loading. Increase in flexural strength was observed with the increase in temperature. A distinct shift in failure mode from compressive to tensile was also found with the rise in test temperatures. Degradation of the porous matrix structure and localized damage of the reinforcing fibers were observed. Weibull analysis of the strength data was performed and the variation of the Weibull modulii with temperatures is discussed. Change in the load-deflection behavior with temperatures was examined and a shift from catastrophic to plastic failure was noted. Room temperature fatigue tests were conducted on unnotched virgin specimens using three point beam with stress ratio, R = 0.1 and a frequency of 1 Hz. A S-N diagram was constructed and high sensitivity of the material to the mean load level was observed. Failed as well as untested specimens were C-scanned, and the location and the extent of the damage were identified.