Advertisement

Attenuation and Porosity Estimation Using the Frequency-Independent Parameter Q

  • Kenneth I. McRae
  • Cedric A. Zala
Chapter

Abstract

Much of the significant damage that may be incurred by graphite-epoxy composite materials results in relatively large discrete damage sites such as delaminations. In those instances, the damage is easily and reliably detected using conventional ultrasonic scanning techniques. However, several mechanisms also exist which do not result in the creation of large discrete damage sites, but result in damage which is distributed throughout the material. These mechanisms include the production of porosity due to poor curing procedures, damage resulting from fatigue or overheating of the composite structure in service, and water ingress caused by prolonged exposure of the material. Of these, the detection of porosity during manufacture has received the most attention, although the assessment of damage from the other sources is also important.

Keywords

Acoustic Impedance Void Content Ultrasonic Attenuation Ultrasonic Inspection Bottom Reflection 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    N. Saffari, A. Som and D. T. Green, “Image processing for improved porosity estimation,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 12 (Edited by D. O. Thompson and D. E. Chimenti), Plenum Press, New York, 1993, pp. 905–910.CrossRefGoogle Scholar
  2. 2.
    I. M. Daniel, S. C. Wooh and I. Komsky, “Quantitative porosity characterization of composite materials by means of ultrasonic attenuation measurements,” J. Nondestr. Eval. 11, 1–8 (1992).CrossRefGoogle Scholar
  3. 3.
    D. K. Hsu and S. M. Nair, “Evaluation of porosity in graphite-epoxy composites by frequency dependence of ultrasonic attenuation,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 6 (Edited by D. O. Thompson and D. E. Chimenti), Plenum Press, New York, 1987, pp. 1185–1193.Google Scholar
  4. 4.
    D. K. Hsu and A. Minachi, “Defect characterization in thick composites by ultrasound,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 9 (Edited by D. O. Thompson and D. E. Chimenti), Plenum Press, New York, 1990, pp. 1481–1488.Google Scholar
  5. 5.
    P. H. Johnston, W. P. Winfree, E. R. Long, Jr., S. M. Kullerd, N. Nathan and R. D. Partos, “Thermal and ultrasonic evaluation of porosity in composite laminates,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 11 (Edited by D. O. Thompson and D. E. Chimenti), Plenum Press, New York, 1992, pp. 1555–1562.Google Scholar
  6. 6.
    S. H. Bickel and R. R. Natarajan, “Plane-wave Q deconvolution,” Geophysics 50, 1426–1439 (1985).CrossRefGoogle Scholar
  7. 7.
    K. P. Bube and R. Burridge, “The one-dimensional inverse problem of reflection seismology,” SIAM Review 25, 497–559 (1983).MathSciNetMATHCrossRefGoogle Scholar
  8. 8.
    O. Rioul and M. Vetterli, “Wavelets and signal processing,” IEEE SP Magazine, 14–38 (October 1991).Google Scholar
  9. 9.
    I. Daubechies, “Ten lectures on wavelets,” CBMS-NSF Conference Series in Applied Mathematics, SIAM, Philadelphia, PA (1992).Google Scholar

Copyright information

© Plenum Press, New York 1995

Authors and Affiliations

  • Kenneth I. McRae
    • 1
  • Cedric A. Zala
    • 2
  1. 1.Defence Research Establishment PacificF. M. O.VictoriaCanada
  2. 2.Barrodale Computing Services Ltd.VictoriaCanada

Personalised recommendations