2009•AIP conference proceedingsRequires access
INTERPRETATION OF A MODE CONVERTED GUIDED WAVE SIGNAL FROM A PIPING MOCKUP BY A MAGNETOSTRICTIVE STRIP TRANSDUCER
Yong Moo Cheong, Shin Kim, Donald O. Thompson, Dale E. Chimenti
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Abstract
A torsional guided wave by a magnetostrictive strip transducer technique has a advantage that the wave patterns are relatively clear and simple when compared to a conventional piezoelectric ultrasonic transducer. If we can characterize the evolution of those defect signals, it could be a promising tool for a structural health monitoring of pipes for a long period of time as well as an identification of flaws. However, an examiner need to be careful when evaluating a signal during a realistic field examination because of some spurious signals or false indications, such as signals due to a directionality, multiple reflections, mode conversion, geometrical reflections etc. In this paper, mode converted signals from a realistic piping mockup are analysed. We found mode conversions between a torsional guided wave T(0,1) mode and a flexural F(1,3) or longitudinal L(0,2) mode generated by a magnetostrictive strip transducer. Based on the experimental observations, an interpretation of the source of the mode conversion is discussed.