Ultrasonic Velocity and Attenuation: Measurement Methods with Scientific and Industrial Applications

Analytical ultrasonics in materials research and testing

“…Experimental results show that equation (14) is appropriate for fitting attenuation data over a frequency range that spans the Rayleigh scattering regime for a variety of polycrystalline materials (Papadakis, 1964a(Papadakis, , 1976BozorgGrayeli, 1981;Hull, 1982, 1983). …”

“…interfaces, expressions for R (and the quantity G, defined below) would simply assume frequency-dependent forms (Papadakis, 1976 (16) is…”

“…For an ideal interface between two nondlspersive media with unequal acoustic impedances, R is independent of ultrasonic frequency (Papadakis, 1976;Generazio, 1984).…”

Wavelet Transform Signal Processing Applied to Ultrasonics

“…Since each progressive wave component propagates with a different phase velocity, the initial shape of the transient waveform is distorted in time. The majority of absolute ultrasonic velocity data have been obtained using time-of-flight methods [11], such as pulse-echo-overlap or double-pulse superposition methods [12], [13]. The time-scale representations obtained using the wavelet transform can be used to analyze the dispersive nature of the material on which the ultrasonic wave is propagating.…”

Transfer function concept for ultrasonic characterization of material microstructures

“…Attenuation Coefficient Papadakis (1968;1976) has demonstrated that the attenuation coefficient can be found by frequency spectrum analysis and that it may be written as (=A where x is the sample thickness. The attenuation coefficient e is a function of frequency and hence as with the quantities T, BI, and B2, it is appropriate to treat it as a Fourier transform of a time-domain quantity.…”