9. Ultrasonics, Bulk Waves
Ultrasonic spectrum analysis is used to study the frequency and angular behavior of diffracted longitudinal waves from elliptical cracks with arbitrary orientation in diffusion bonded titanium alloy. The aspect ratio of the cracks (ratio of major to minor axis) ranged from 1 to 8 and the bandwidth of the input signal was such that the scattering diameter was ka ≥ l. The experimental data are analyzed based on a recently developed elastodynamic diffraction theory (by Achenbach et al.). Some of the key parameters of the scattering data are identified to address the inverse problem.
Adler, Laszlo and Lewis, D. Kent, "Diffraction of Ultrasonic Waves by Elliptical Cracks in Metals" (1980). Proceedings of the DARPA/AFML Review of Progress in Quantitative NDE, July 1978–September 1979. 56.