Share Email Print

Proceedings Paper

Evaluating the mechanical behavior of notched SiC/SiC composites using thermoelastic stress analysis
Author(s): Andrew L. Gyekenyesi; Gregory N. Morscher
Format Member Price Non-Member Price
PDF $17.00 $21.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Ceramic matrix composites (CMCs) are potential materials for high temperature applications in gas turbines. Currently, the main areas of consideration include combustor liners and turbine vanes. Because these components contain stress concentrations, it is imperative that candidate materials be fully assessed concerning behavior related to stress risers. In this study, the stress fields adjacent to machined notch roots were examined for woven SiC fiber reinforced, melt infiltrated SiC matrix composites with a BN interphase, utilizing either Hi-NicalonTM fibers or the stiffer Sylramic fibers. The double-edge notched tensile test approach was used for multiple notch sizes. In addition, the materials ability to diffuse stress concentrations by inelastic damage mechanisms was considered. The damage was induced by applying predetermined tensile stresses known to cause matrix cracking. The thermoelastic stress analysis technique (TSA, also recognized as SPATE: Stress Pattern Analysis by Thermal Emission) was utilized to define the stress profile on the specimen surface. TSA is based on the fact that materials experience small temperature changes when compressed or expanded. When subjecting a structure to a cyclic load, a related cyclic temperature profile results. The surface temperature profile, measured with an infrared camera, is directly related to the surface stresses on the structure. The amplitude of the TSA signal is defined to be linearly dependent on the cyclic stress amplitude. Here, results were provided concerning the stress concentration behavior as a function of notch length, damage level, as well as the mean stress during TSA measurements.

Paper Details

Date Published: 12 April 2004
PDF: 10 pages
Proc. SPIE 5405, Thermosense XXVI, (12 April 2004); doi: 10.1117/12.544544
Show Author Affiliations
Andrew L. Gyekenyesi, NASA Glenn Research Ctr. (United States)
Gregory N. Morscher, NASA Glenn Research Ctr. (United States)

Published in SPIE Proceedings Vol. 5405:
Thermosense XXVI
Douglas D. Burleigh; K. Elliott Cramer; G. Raymond Peacock, Editor(s)

© SPIE. Terms of Use
Back to Top