TY - GEN
T1 - Enhancement of the selectivity of closed cracks in nonlinear ultrasonic imaging using amplitude difference phased array
AU - Ohara, Yoshikazu
AU - Ikeuchi, Masako
AU - Jinno, Kentaro
AU - Ouchi, Akihiro
AU - Horinouchi, Satoshi
AU - Yamanaka, Kazushi
PY - 2012/1/1
Y1 - 2012/1/1
N2 - Subharmonic waves realize a high selectivity for closed cracks. However, when a short-burst wave is used to achieve a high temporal resolution, not only closed cracks but also linear scatterers appear in the subharmonic image owing to leakage in frequency filtering. They are ghosts that degrade the selectivity for closed crack in the subharmonic image. Here, we propose an amplitude difference phased array (ADPA), where the ghosts are eliminated by subtracting a subharmonic image at a small input multiplied by the input amplitude ratio from that at a large input. We verified the ADPA method by a two-dimensional simulation based on the finite difference time domain (FDTD) method with damped double nodes (DDNs) for subharmonic imaging of closed cracks. Furthermore, the ADPA method was experimentally verified in a closed-crack specimen.
AB - Subharmonic waves realize a high selectivity for closed cracks. However, when a short-burst wave is used to achieve a high temporal resolution, not only closed cracks but also linear scatterers appear in the subharmonic image owing to leakage in frequency filtering. They are ghosts that degrade the selectivity for closed crack in the subharmonic image. Here, we propose an amplitude difference phased array (ADPA), where the ghosts are eliminated by subtracting a subharmonic image at a small input multiplied by the input amplitude ratio from that at a large input. We verified the ADPA method by a two-dimensional simulation based on the finite difference time domain (FDTD) method with damped double nodes (DDNs) for subharmonic imaging of closed cracks. Furthermore, the ADPA method was experimentally verified in a closed-crack specimen.
KW - Amplitude difference phased array (ADPA)
KW - closed cracks
KW - damped double node (DDN)
KW - nonlinear ultrasonic imaging
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M3 - Conference contribution
AN - SCOPUS:84869447822
SN - 9781467322591
T3 - Proceedings of the SICE Annual Conference
SP - 1177
EP - 1180
BT - 2012 Proceedings of SICE Annual Conference, SICE 2012
PB - Society of Instrument and Control Engineers (SICE)
T2 - 2012 51st Annual Conference on of the Society of Instrument and Control Engineers of Japan, SICE 2012
Y2 - 20 August 2012 through 23 August 2012
ER -