Analysis of internal wave reflection within a magnetostrictive patch transducer for high-frequency guided torsional waves

Review of magnetostrictive patch transducers and applications in ultrasonic nondestructive testing of waveguides

“…If high-frequency torsional waves in a range of megahertz frequencies need to be generated by torsional MPTs, impedance matching at the interface between the bare part and the magnetostrictive patch-bonded part of a test pipe should be considered to avoid any distortion of the generated waves [61]. Fig.…”

“…The performance improvement of MPTs is, however, an issue, so studies on mechanical impedance matching [61], magnetic flux concentration [62], and phased arraying for the selection of a specific mode [63] have been conducted. Various MPT applications were also reported for rotating shafts [64], wire ropes/cables and anchor rods [65], pipelines with mechanical attachments [66], pipes with axial cracks [67], and inspections of various defects and imaging [68][69][70][71][72][73].…”

High-frequency lowest torsional wave mode ultrasonic inspection using a necked pipe waveguide unit

“…Referring to Fig. 1, the transmitting and receiving torsional magnetostrictive transducers [13,14] are installed in Regions 1 and 3, respectively (the detailed configurations of the magnetostrictive transducers used and the data acquisition procedure will be given in Section 2.4). Because Region 3 will be connected to an open end of a test pipe by a couplant, the inner and outer radii of Region 3 should be the same as those of the test pipe to match the mechanical impedance between Region 3 and the test pipe.…”

Development of an omni-directional shear horizontal mode magnetostrictive patch transducer

“…Ultrasonic guided waves with high energy and high signal-to noise ratio will transfer from nickel patch to inspected structures. It should be noted that the edges of nickel patch need to be polished and thinned to suppress undesirable additional trailing pulses in received ultrasonic guided wave signals [13].…”