Pulse Echo Technique to Determine Bondline Reflection Coefficients
Using reflection coefficients to obtain bond strengths and other bondline characteristics has been proposed by previous researchers(1,2). For configurations where the bondline of interest is well separated from the specimen surface and adjacent boundaries, measuring the reflection coefficient using broadband, pulse-echo, ultrasound can be done by processing the bondline echo taken directly from the A-scan. For configurations where the bondline is close to a parallel surface however, reverberations in the layer between the bondline and surface will cause successive bondline echoes to overlap in the A-scan, so that individual echoes can not be processed to determine the reflection coefficient directly. This paper presents a technique for processing the A-scan to obtain the desired reflection coefficient for the case when the bondline is near a surface.
KeywordsReflection Coefficient Synthetic Experiment Nondimensional Frequency Adjacent Boundary Quantitative Nondestructive Evaluation
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- 1.Sotiropoulos, D.A. and Achenbach, J.D., “Reflection by Distributed Microflaws in a Diffusion Bond”, Review of Progress in QNDE, vol. 8, Plenum Press, 1989.Google Scholar
- 2.Margetan, F., Gray, T.A., and Thompson, R.B., “Oblique-Incidence UT Inspection of Diffusion Bonds”, Review of Progress in QNDE, vol. 8, Plenum Press, 1989.Google Scholar
- 5.Angel, Y.C. and Achenbach, J.D., “Reflection and Transmission of Elastic Waves by a Periodic Array of Cracks”, Journal of Appl. Mech., vol. 52, 1985.Google Scholar
- 6.Thompson, R.B. and Fiedler, C.J., “The Effects of Crack Closure on Ultrasonic Scattering Measurements”, Review of Progress in QNDE-3, Plenum Press, 1984.Google Scholar
- 7.Cohen, T.J., “Source-Depth Determination Using Spectral, PseudoAutocorrelation, and Cepstral Analysis”,Geophys. J. Roy. Astron. Soc., vol. 20, 1970.Google Scholar