Broadband Fields Radiated in a Solid by Water-Coupled Transducers: A Comparison of Approximate Models, Numerical Approaches and Experiments

Calculation of Wideband Ultrasonic Fields Radiated by Immersed Transducers into Solids Through Curved Interfaces

“…The wavepath between the source-and field-points is given by (4) where R 1 and Ra are the lengths of the path of stationary phase in the fluid (wavespeed c) and in the solid (for the a = L,T wave of wavespeed ca, (Ja being the refracted angle). The corresponding divergence factor DFptane is given by (see [4] for example), (5) Comparisons have been made (in 2-D) of results computed using the full angular spectrum with results obtained underGO [1]. They show excellent agreement of both solutions when field-points are at ranges Ionger than one wavelength in the solid medium.…”

Integrated Models of Ultrasonic Examination for NDT Expertise

“…Comparisons of the Champ-Sons predictions either with experimental results [2] or with those from finite-element calculations [3], show that the model is accurate as long as the contribution of surface waves can be neglected, i.e., as long as the distance between the field point and the interface is greater than around one wavelength.…”

“…The model adopted in Champ-Sons has been extensively described in this review [2][3][4]. Consequently we only briefly recall here the main features of the underlying theory.…”

“…Two main models have been implemented, covering the most commonly encountered NDT configurations. A first one, called Champ-Sons [2,3], is devoted to the computation of the uhrasonie fields radiated by arbitrary transducers into pieces under inspection. A second one, called Mephisto [4,5], simulates the examination by predicting the echo-structure for each scanning position of the probe.…”

Calculation of Wideband Ultrasonic Fields Radiated by Water-Coupled Transducers into Anisotropic Media

“…The extension is derived by an asymptotic expansion nearby stationary phase points of an integral expressing the refracted angular spectrum (geometrical optics (GO) approximation). Such a method has proved to ensure both computing efficiency and accuracy, when applied to the case of isotropic medium [2]. Specific developments are required in the neighborhood of caustics (directions of higher intensity), for which the asymptotic expansion is performed to a higher order.…”