Damage Detection in a Plate by Using Beam-Focused Shear-Horizontal Wave Magnetostrictive Patch Transducers

Yoon Young Kim, Ju Seung Lee, Seung Hyun Cho, Byung Chul Jeon, Hoe Kim
2009 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference   unpublished
For efficient non-destructive ultrasonic inspection in plate/shell structures, the development of a guided-wave based method using transducers having good beam directivity, high power and little dispersion is important. To this end, a damage inspection strategy using a set of specially-designed magnetostrictive patch transducers capable of generating beam-focused, non-dispersive shear-horizontal waves is proposed. In the present ultrasonic pitch-catch inspection, only a few single transducers
more » ... ingle transducers need to be installed around an inspection area. To convert measured wave signals by the transducers into two-dimensional images, a relatively simple yet effective data-processing technique suitable for the employed transducer setting is developed. Sets of experiments were conducted on rectangular plates having one or two circular holes with a diameter of 1 mm or 3 mm. For all experiments, the Gabor-shaped ultrasonic pulses having the center frequencies of 250 kHz and 360 kHz were used. Nomenclature n A = region of influence for a grid point n. s c = shear wave speed. D = interval between solenoids in PSA (Planar Solenoid Array). , ( ) n i j E t = envelope of the voltage output signal at a specific arrival time t from i to j via n. f = center frequency. G = spacing between virtual grid points. n h = the size of n A . , ( ) n i j I n = squared magnitude of the wave scattered from a grid point n when ( i T , j R ) is used.
doi:10.2514/6.2009-2381 fatcat:a43jwswk2nenlb2kdm4ssbp4ba