Surface Evaluation Using Acoustic Emission

  • J. J. Schuldies
Part of the Fracture Mechanics of Ceramics book series (FMOC, volume 1)


Artificially induced surface flaws in dense silicon nitride may be activated by applying a thermal stress with a CO2 laser to the near surface of the material. The extension of these flaws may then be recorded by acoustic emission (AE) instrumentation and this response then serves as an indication of surface integrity. Surface degradation of test specimens was achieved by thermal shocking with the laser to produce surface cracks. The laser was then used to thermally stress the near surface and activate the small cracks. Flexural tests were used to determine the extent of damage by noting the reduction in strength associated with various levels of AE recorded during laser thermal shocking. Utilizing these parameters on an unknown surface should result in obtaining meaningful data in terms of the presence of surface defects and their influence on material strength.


Acoustic Emission Flexural Strength Surface Crack Crack Extension Acoustic Emission Event 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Duegan, H. L., Harris, D. O., “Acoustic Emission — A New Nondestructive Testing Tool,” Ultrasonics, V. 7, No. 3, July 1969.Google Scholar
  2. 2.
    Graham, L. J., Alers, G. A., “Investigation of Acoustic Emission From Ceramic Materials”, North American Rockwell/ Science Center, Final Report, Naval Air Systems Command Contract No. N00019-71-C-0344, May, 1972.Google Scholar
  3. 3.
    Graham, L. J., Alers, G. A., “Acoustic Emission From Polycrystalline Ceramics”, North American Rockwell/Science Center, Final Report, Naval Air Systems Command Contract No. N00019-72-C-0382, December, 1972.Google Scholar
  4. 4.
    Schuldies, J. J., “The Acoustic Emission Response of Mechanically Stressed Ceramics”, to be published in Materials Evaluation.Google Scholar
  5. 5.
    Romrell, D. M., Bunnell, L. R., “Monitoring of Crack Growth in Ceramic by Acoustic Emission”, Materials Evaluation, December, 1970.Google Scholar
  6. 6.
    Wright, R. E., “Acoustic Emission of Aluminum Titanate”, J. American Ceramic Soc. 55, p. 54, January, 1972.Google Scholar
  7. 7.
    McLean, A. F., “The Application of Ceramics to the Small Gas Turbine”, ASME Paper No. 70-Gt-105.Google Scholar
  8. 8.
    Engineers Guide to Structural Ceramics, Special Report, Materials Engineering, November, 1970.Google Scholar
  9. 9.
    Hardy, H. R., Jr., “Application of Acoustic Emission Techniques to Rock Mechanics Research,” Acoustic Emission, ASTM STP 505, American Society for Testing and Materials, 1972, pp. 41–83.Google Scholar

Copyright information

© Plenum Press, New York 1974

Authors and Affiliations

  • J. J. Schuldies
    • 1
  1. 1.Ford Motor CompanyDearbornUSA

Personalised recommendations