Pulse-Echo Harmonic Generation Measurements for Non-destructive Evaluation

S. R. Best*, A. J. Croxford, S. A. Neild

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

13 Citations (Scopus)
344 Downloads (Pure)

Abstract

Ultrasonic harmonic generation measurements have shown great potential for detecting nonlinear changes in various materials. Despite this, the practical implementation of the technique in non-destructive evaluation (NDE) has typically been limited to the through transmission setup case, with which problems arise in certain situations. Recently, works in the fields of nonlinear fluids and biomedical imaging have reported different application of the harmonic generation theory by making use of reflective boundaries and beam focusing. It is thought that such techniques may be similarly applied in the field of NDE to enable single-sided nonlinear inspection of components. In this paper, we initially describe a numerical model which has been used to determine the effects of attenuation and acoustic beam diffraction on measurements of the nonlinear parameter beta. We then extend the model to incorporate first the effects of multiple reflecting boundaries in the propagation medium, then of focused source excitation. Simulations, supported by experimental data, show that nonlinear pulse-echo measurements have the potential to provide a viable (and practical) alternative to the usual through-transmission type as a means of measuring beta in solids. Furthermore, it is shown that such measurements may be optimised, both by adjusting the excitation frequency, and by focusing the acoustic source at a certain point relative to the specimen boundary.

Original languageEnglish
Pages (from-to)205-215
Number of pages11
JournalJournal of Nondestructive Evaluation
Volume33
Issue number2
Early online date3 Dec 2013
DOIs
Publication statusPublished - Jun 2014

Keywords

  • Nonlinear
  • Ultrasonics
  • AMPLITUDE ULTRASONIC WAVES
  • NONLINEAR ACOUSTICS
  • FATIGUE DAMAGE
  • SOUND BEAM
  • FINITE
  • REFLECTION
  • NEARFIELD
  • DISTORTION
  • RADIATION
  • PISTON

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