Absolute Sensitivity of Air, Light and Direct-Coupled Wideband Acoustic Emission Transducers

  • E. S. Boltz
  • C. M. Fortunko
  • M. A. Hamstad
  • M. C. Renken


Previous work has compared the relative performance of various wide-band ultrasonic transducers used as receivers [1]. Studies have also been made comparing the merits of various optical sensors [2] and evaluating their applicability to acoustic emission (AE) [3]. In this paper, the calculated and measured sensitivities of such transducers are compared with the sensitivity of transducers capable of detecting low amplitude AE events in steels [4, 5]. While optical sensors appear to provide many practical advantages over contact sensors, particularly at very low frequencies, it is found that they cannot meet the sensitivity requirements for wide-band AE detection in metals. Furthermore, it is found that a new transducer, recently developed at NIST, has sufficient sensitivity for such applications. In particular, this high-fidelity, high-sensitivity (HFHS) sensor is found to exhibit sensitivity which approaches the “thermal rattle” limit in aluminum within 10 dB over the 250 kHz to 1 MHz region. Also, it is shown that the new transducer’s noise floor is well below both the necessary sensitivity level to monitor AE in metals and the sensitivity limits of both optical and airborne-sound transducers. Furthermore, its performance is in good agreement with the computer model used in its design.


Acoustic Emission Surface Acoustic Wave Acoustic Emission Event Thermal Limit Michelson Interferometer 
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  1. 1.
    Dewhurst, R.J., Edwards, C.E., McKie, A.D.W., and Palmer, S.B., Ultrasonics 25, 1987.Google Scholar
  2. 2.
    Monchalin, J.-P., IEEE Trans. on Ultrasonics, Ferroelectrics and Frequency Control, UFFC-33(5), 1986.Google Scholar
  3. 3.
    Palmer, C.H., and Green, R.E., Jr., Chapter 15, Nondestructive Evaluation of Materials, 1979.Google Scholar
  4. 4.
    Scruby, C.B. and Wadley, H.N.G., “Acoustic Emission for NDE in the Nuclear Industry,” AERE-R 10537, 1982.Google Scholar
  5. 5.
    Wadley, H.N.G. and Simmons, J.A., Part 4, Section 3, Nondestructive Testing Handbook, 5(19), 1987.Google Scholar
  6. 6.
    Greenspan, M., J. Acoust. Soc. Am. 81(1), 1987, 173–183.MathSciNetCrossRefGoogle Scholar
  7. 7.
    Debye, P., Ann. Physik, 43, 49, 1914.Google Scholar
  8. 8.
    Waller, I., Dissertation, Uppsala, 1925.Google Scholar
  9. 9.
    Ott, H., Ann. Physik, [5] 23, 169, 1935.CrossRefGoogle Scholar
  10. 10.
    Maradudin, A.A., Montroll, E.W. and Weiss, G.H., Theory of Lattice Dynamics in the Harmonic Approximation, in Solid State Physics Supplement 3, Seitz and Turnbull eds., 1963.Google Scholar
  11. 11.
    Tewary, V.K., private communication.Google Scholar
  12. 12.
    Callen, H.B. and Welton, T.A., Physical Review, 83(1), 1951, 34–40.MathSciNetCrossRefMATHGoogle Scholar
  13. 13.
    Tarnow, V., J. Acoust. Soc. Am., 82(1), 1987, 379–81.CrossRefGoogle Scholar
  14. 14.
    Wagner, J.W. and Spicer, J.B., J. Opt. Soc. Am., 4(8), 1987, 1316–26.CrossRefGoogle Scholar
  15. 15.
    Whitman R.L. and Korpel, A., Appl. Opt., 8(8), 1969.Google Scholar
  16. 16.
    Proctor, T.M., Jr. (1980), J. Acoust. Soc. Am. Suppl. 1, 68, S568.CrossRefGoogle Scholar
  17. 17.
    Fortunko, C.M., Hamstad, M.A., to be published.Google Scholar
  18. 18.
    Fortunko, C.M., Hamstad, M.A., and Fitting, D.W., “High-fidelity acoustic-emission sensor/preamplifier subsystems: modeling and experiments,” IEEE Ultrasonics Symposium, 1992, 327-333.Google Scholar
  19. 19.
    Motchenbacher, C.D. and Fitchen, F.C., Low Noise Electronic Design, 1972.Google Scholar

Copyright information

© Plenum Press, New York 1995

Authors and Affiliations

  • E. S. Boltz
    • 1
  • C. M. Fortunko
    • 1
  • M. A. Hamstad
    • 1
  • M. C. Renken
    • 1
  1. 1.Materials Reliability DivisionNational Institute of Standards and TechnologyBoulderUSA

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