Flexible patch unlocks potential of ultrasound for inspecting irregular components

Ultrasound is often used in engineering to detect cracks in metal components. But its usefulness is sometimes limited by the shape of the probe used to direct the high-frequency sound waves into the metal. Ultrasound emitters tend to be flat-bottomed, so if the surface to be tested is not perfectly flat as well, the emitter cannot make a good contact on the component and the technique cannot be used.

“Elbows, corners and other structural details happen to be the most critical areas in terms of failure – they are high stress areas,” said Francesco Lanza di Scalea, a structural engineer from University of California San Diego (UC San Diego) and lead author on the study of the new method of inspecting irregularly-shaped objects. “Conventional rigid, flat probes aren’t ideal for imaging internal imperfections inside these areas.”

Although gels, oils or even water can create better contact between the probe base and the surface, using too much of these can dull some of the signals. Moreover, conventional emitters are quite bulky, so difficult to get into areas with convoluted geometry.