UT – SDH: Side Drilled Holes at different depths and Immersion probes
Summary
Global overview:
Immersion probes | 2.25 MHz Ø19 mm | 2.25 MHz Ø12.7 mm | 2.25 MHz Ø6.35 mm | 2.4 MHz Ø20 mm | 4.5 MHz Ø12.7 mm | 4.7 MHz Ø6.35 mm |
P0° | Done | Done | Done | Done | ||
P45° | Done | Done | ||||
P60° | Done | Done | ||||
SV45° | Done | Done | Done | Done | ||
SV50° | Done | Done | ||||
SV55° | Done | Done | ||||
SV60° | Done | Done |
Configuration
This validation experiment deals with Ø2 mm SDH at different depths. The measurements are performed upon a planar steel block containing Ø2 mm SDH from 4 to 60 mm depth with 4 mm steps. As a reminder, the steel parameters are: density 7.9, P waves velocity: 5900 m/s and SV waves velocity: 3230 m/s. Since the SDH are inspected perpendicularly to their axis, the SOV interaction model is considered.
Frequency | Crystal | Mode | Water path | Calibration depth |
2.25 MHz | 19 mm | P0° | 50 mm | 20 mm |
12.7 mm | P0° | 50 mm | 12 mm | |
6.35 mm | SV45°, P0° | 20 mm | 12 mm (P0°-20mm) | |
2.4 MHz | 20 mm | SV45°, SV60°, P45°, P60°, P0° | 50 mm | 32 mm (SV45°) |
4.5 Mhz | 12.7 mm | SV45° à SV60° | 20 mm | 32 mm (SV45°) |
4.7 MHz | 6.35 mm | P et SV, de 45°à 60° | 25 mm | 4 mm (P45°) |
RESULTS
For each probe, the simulated P or/and SV beam radiated in the specimen and in the incidence plane is displayed for at least one configuration.
Conclusion
Results show a good agreement with generally less than 2 dB difference for mono-element immersion probes.
The discrepancy may be a little higher in the near field. This is due to limitations of the model and is explained in details for rectangular contact probes.
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