UT - Comparison FBH SDH: A-scan analysis

An additional study is carried out concerning the A-scans of the signals with one contact probe and the phased-array probe with the previous configuration.



For the Ø6.35 mm contact probe, the echoes from all reflectors are well estimated.



All the A-scans show a good agreement between experiment and simulation.


Phased-array CONTACT probe of 20 ELEMENTS with 0.7 mm PITCH at 5 MHz

For the contact phased-array probe, the echoes from all reflectors are well estimated.



The A-scans of the specular echoes generated by the holes are well estimated by CIVA.

Moreover, the A-scans enlighten the fact that a creeping wave is also present for associated SV mode echo. This creeping wave propagates around the circumference of a SDH and creates an additional echo, which is also correctly predicted.



A good agreement is obtained between the measured and simulated amplitudes of the specular responses of SDH of different diameters relatively to the specular response of a FBH (discrepancy less than 1 dB).

Depending on the probe and the mode (P or SV), the experimental direct echoes of the three SDH are stronger or weaker than the experimental FBH direct echo. This relation is well reproduced in simulation. In most cases, the shapes of the simulated FBH and SDH echoes are very close to the experimental one for both SV45° and P45° modes (once the input signal is well calibrated).

The creeping wave (see the SDH A-scans obtained for SV modes) is well simulated in all cases (good shape, position in time and amplitude relatively to the specular contribution), although some discrepancies occur on the smallest SDH.


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