Which wave type is most affected by surface irregularities during ultrasonic testing?

Surface waves are particularly sensitive to surface irregularities because they propagate along the surface and are influenced by the conditions of that interface. In ultrasonic testing, surface waves travel by deforming the material in both vertical and horizontal directions, making them highly responsive to any changes or imperfections found at the material surface.

When such irregularities are present, they can scatter or reflect the energy of the surface waves, making these waves an effective means of detecting flaws like cracks, pits, or variances in coating thickness. The nature of surface waves, which predominantly interact with the material's surface, inherently makes them more susceptible to disruptions caused by these irregularities compared to other wave types.

Longitudinal and shear waves, on the other hand, primarily propagate through the bulk of the material rather than along the surface. While they can be affected by internal flaws or misalignments, they do not interact with surface irregularities in the same way as surface waves do. Rayleigh waves, a subset of surface waves, also experience similar effects as they travel along the surface but are less commonly referred to in the context of the most affected wave type in general ultrasonic testing scenarios.

Thus, recognizing that surface waves are specifically designed to respond to surface features reinforces why they are the wave