When differences between CIVA 11 and experiments (for the Ø12.7mm and Ø6.35mm probes) were observed, simulations with CIVA 2D and the finite elements code ATHENA2D coupled with CIVA were performed.
The comparisons of experimental and simulated (CIVA, CIVA2D and ATHENA2D) backwall echoes just above the defect are presented below.
In this particular case where amplitudes obtained with 2D codes (ATHENA2D and CIVA2D) are compared to 3D ones (experiments and CIVA11), the reference is the non-shadowed backwall echo amplitude. The Ø2mm SDH was not chosen as reference since it has not the same extension and is not located at the same depth as the studied shadowed backwall. Thus, the “3D” effect of the extension is not the same for the SDH and for the backwall and it is not possible to compare respectively their 2D and 3D amplitudes.
For both Ø12.7mm and Ø 6.35mm probes, there is a very good agreement for all defects depths between experiment and ATHENA2D for the shadowed backwall echo just above the defect. The maximum differences are less than 1dB.
The figure below shows a comparison between experimental and ATHENA2D echodynamic curves. There is a very good agreement for the maximal amplitude and shape curves for both probes.
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