Guided Wave Ultrasonic Systems and Probes

Start with what is not different between magnetostrictive and piezoelectric guided wave systems.

Once the wave is in the pipe, it is the same wave. The same T(0,1) mode, the same velocity, the same dispersion behavior, the same reflection from a change in cross-sectional area, the same analysis. The transducer only decides how the local deformation is produced at the surface. It does not change the physics of what travels down the line. Guided wave testing is one method, not two.

What does differ is probe geometry, and it has one consequence an inspector can measure.

A continuous encircling probe generates one wave front around the full circumference from the start. A probe built from discrete elements generates a separate wavelet at each element, and those wavelets need distance to merge into a single front. That distance is the near field length. Until the wavelets merge, the signal in that region is not a clean guided wave, and a defect sitting there is hard to resolve.

That is not a marketing difference. It is geometry, and it sets how close to the probe you can trust an indication. The module works through it alongside the dead zone, which limits the same region for a different reason.

If you have ever had to explain to a client why the first several feet of a scan are not reportable, this is the explanation.