Chapter 44. C-Coupon Studies of SiC/SiC Composites Part I: Acoustic Emission Monitoring

  1. Hua-Tay Lin and
  2. Mrityunjay Singh
  1. Gregory N. Morscher1,
  2. Frances I. Hurwitz2 and
  3. Anthony M. Calomino2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294741.ch44

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

How to Cite

Morscher, G. N., Hurwitz, F. I. and Calomino, A. M. (2002) C-Coupon Studies of SiC/SiC Composites Part I: Acoustic Emission Monitoring, in 26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3 (eds H.-T. Lin and M. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294741.ch44

Author Information

  1. 1

    Ohio Aerospace Institute NASA Glenn Research Center, MS 106–5 Cleveland OH, 44135

  2. 2

    NASA Glenn Research Center Cleveland OH, 44135

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2002

ISBN Information

Print ISBN: 9780470375785

Online ISBN: 9780470294741

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Keywords:

  • acoustic emission;
  • SiC;
  • deviation;
  • interlaminar tensile;
  • C-coupon tests

Summary

Modal acoustic emission (AE) was used to monitor the acoustic activity during room temperature and elevated temperature c-coupon tests for a variety of SiC/SiC systems including composites containing Sylramic®, ZMI™, or Hi-Nicalon™ fibers with meit-infiltrated or polymer-infiltrated SiC matrices. Modal AE proved excellent at monitoring matrix cracking in the curved portion of the C-coupon specimen with increasing load. This included the load at which the first AE event occurred and the location of AE events during the test that were, presumably, caused by the formation and growth of interlaminar cracks and, at higher loads, transverse cracks. Graphical techniques were employed to estimate the load for 1st AE. It was determined that for this test with these material systems, the first AE could be estimated within the load range bounded by the load at which initial deviation from linearity of the load-displacement curve occurs and the load where the 98% offset of the linear regression fit intercepted the load-displacement curve. The calculation of interlaminar tensile stress from the load for 1st AE was determined for all the systems. Ultimate ILT strength usually corresponded to ILT stress determined from the ultimate load to failure of the C-coupon test, which was considerably higher than the first cracking stress.