Elastic-Wave Propagation in Random Polycrystals: Fundamentals and Application to Nondestructive Evaluation

Velocity and attenuation of scalar and elastic waves in random media: A spectral function approach

“…A good summary of the seismological research can be found in the monograph of Sato and Fehler (1998). A review article covering a number of theoretical and experimental results from non-destructive evaluation has been written by Thompson (2002).…”

Propagation and scattering of ultrasonic waves in polycrystals with arbitrary crystallite and macroscopic texture symmetries

“…The scattering depends on ultrasonic frequency, grain size 46 and shape, and the elastic properties of the crystallites and the macroscopic preferred orientation of the 47 crystallites (texture). The grain scattering mechanism dominates different absorption mechanisms in the 48 bulk of the crystallites; however, eventually the scattering energy dissipates to heat due to absorption Most past studies address ultrasonic scattering in polycrystals with equiaxed grains of high 55 crystallographic symmetry and absence of preferred crystallite orientation [2][3][4][5]16,[22][23][24]. However, most 56 manmade materials have some form of texture, for example composite materials due to fiber orientation 57…”

“…In many cases, the 37 objective is scatter [2] suppression to increase signal-to-noise ratio and image improvement. In others, as 38 was recently realized, by measuring scattering noise one can obtain important information on medium 39 inhomogeneities and microstructure leading to new wave diagnostic modalities that have importance for 40 diagnostics of different states of materials and tissues and for geosciences [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. 41…”

“…In many imaging applications-nondestructive evaluation, seismology and medical ultrasonics-elastic 36 wave scattering in stochastically-varied inhomogeneous media is of importance [1][2][3][4][5]. In many cases, the 37 objective is scatter [2] suppression to increase signal-to-noise ratio and image improvement.…”

Wigner distribution of a transducer beam pattern within a multiple scattering formalism for heterogeneous solids

“…͑70͒ is related to the transducer beam model. The term in square brackets ͓͑ /2͒ ϫ͑ 0 4 / c L 8 ͒͑͒⌶ ....p p q q ....p p q q ͔͑͒ is known as the diffuse backscatter coefficient, 17,56 which depends on the microstructural properties of the material and thus controls the amplitude of the SSR. Equation ͑70͒ is the third primary result of this article, a quantity that may be compared directly with experiments involving transducers.…”