Corner echoes with SV mode: Influence of the notch length

CONFIGURATION

In the following configuration, the specimen is a steel planar mock-up of 20 mm thickness containing 4 backwall breaking notches: 4 notches of dimensions 2×2 mm, 2×5 mm and 2×15 mm, and a notch of dimensions 6×15 mm.

Two immersion probes are used:

Frequency	Crystal	Mode	Water path	Calibration depth
2.25 MHz	Ø6.35 mm	SV45	20 mm	20 mm
4.5 MHz	Ø12.7 mm	SV45	20 mm	15 mm

Results

Each notch is associated with a number in order to facilitate the results presentation:

Notch number	1	2	3	4
Height	2 mm	2 mm	2 mm	6 mm
Length	2 mm	5 mm	15 mm	15 mm

A SV45 inspection is performed with the circular immersion probe of Ø6.35 mm diameter functioning at 2.25 MHz with 20 mm water path. The input signal has a central frequency of 2.25 MHz, a bandwidth of 64% and a phase of 290°.

The results are calibrated relatively to a Ø2 mm SDH of 40 mm length and located at 20 mm depth.

The results show a good agreement between experiments and simulation: the discrepancies are less than 2 dB.

A SV45 inspection is performed with the circular immersion probe of Ø12.7 mm diameter at 4.5 MHz with 20 mm water path. The input signal has a central frequency of 4.5 MHz, a bandwidth of 73% and a phase of 270°.

The results are calibrated relatively to a Ø2 mm SDH of 40 mm length and located at 15 mm depth.

A good agreement is observed between experiments and simulation. The difference is always less than 0.5 dB.

The results show that the notch height does not affect the SV corner echo mode simulated with CIVA.

Continue to Simultaneous influence of the 2 dimensions of the notch

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