For discontinuity geometries other than flat, how does the echo amplitude compare to that of a flat defect?

In ultrasonic testing, the echo amplitude is influenced by several factors, including the geometry of the discontinuity. Flat defects, such as cracks or lack of fusion, present a specific interface for the ultrasonic waves to reflect off of, which generally results in echoes with relatively consistent amplitude due to the directivity of waves.

When discontinuity geometries are not flat, such as curved or irregular shapes, the behavior of the ultrasonic waves changes significantly. The wavefronts may scatter in various directions upon hitting these non-planar surfaces, rather than reflecting back in a focused manner towards the transducer. This scattering causes a reduction in the energy of the reflected waves that return to the transducer, leading to a decreased echo amplitude compared to that of flat defects.

The relationship between the geometry of the defect and the echo amplitude is critical for interpreting ultrasonic data. Non-flat geometries can disrupt the alignment necessary for optimal energy reflection, resulting in weaker signals received. Therefore, it can be accurately said that for discontinuity geometries other than flat, the echo amplitude will typically be decreased relative to a flat defect.