RESEARCH PAPERS: Gas Turbines: Ceramics

Nondestructive Evaluation of Thermally Shocked Silicon Carbide by Impact-Acoustic Resonance

[+] Author and Article Information
R. A. Bemis

Caterpillar, Inc., Peoria, IL 60482

K. Shiloh

Soreq Nuclear Research Center, Yavne, Israel

W. A. Ellingson

Argonne National Laboratory, Argonne, IL 60439

J. Eng. Gas Turbines Power 118(3), 491-494 (Jul 01, 1996) (4 pages) doi:10.1115/1.2816673 History: Received March 16, 1995; Online November 19, 2007


Monolithic ceramics are under consideration as structural components for hot-stage sections of gas-fired turbine engines. In addition to manufacturing quality control, other important aspects for this application include life prediction modeling and time between engine overhauls. One nondestructive evaluation (NDE) method that provides information about material condition involves an analysis of resonant vibrations. In previous work by this general approach, changes in modal parameters have been related to bulk defect mechanisms such as microcracking due to thermal shock damage. In this work resonant vibrations from monolithic ceramic specimens were excited by an instrumented impact hammer and detected by a noncontact acoustic microphone over frequencies up to 100 kHz. Computer-based analysis of vibration signatures from test specimens allowed extraction of modal frequencies and damping constants. Downward shifts in detected resonant frequencies and increases in internal friction or (specific) damping capacity measurements were obtained from SiC cylindrical rings, and these measurements were shown to relate to thermal shock severity. This NDE method not only provides measurable parameters that could be used as accept–reject criteria for in-line process inspection, it also provides a means for tracking the mechanical integrity of in-service engine components to support life prediction modeling.

Copyright © 1996 by The American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.





Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In