Application of Magnetostrictive Transducer for the Long-Range Guided Wave Inspection

The leakage of the pipes is a major issue for the safety of industrial structures. However, in many cases, because of their geometrical complexity and inaccessibility, it is difficult to inspect them by the conventional NDE method. A long-range guided wave inspection, thus, is an option to inspect them. A torsional vibration mode, T(0,1) shows many advantages in a long-range guided wave examination of a pipe, such as no dispersion characteristic, no radial displacement and low attenuation. However, it is not easy to fabricate a transducer with an array of piezoelectric elements for generation of torsional vibration mode and even expensive. Recently a magnetostrictive metal strip sensor was used for a generation of the torsional vibration modes in a pipe and this technique has shown several advantages for practical applications. This study investigated the applicability of a long-rang guided ultrasonic method to the detection of artificial notches even in the presence of various foreign objects.