P3-25 超音波の非線形応答による閉じたき裂画像化のための入射波振幅の最適化(ポスター発表)

概要

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To image closed cracks, we constructed a novel imaging apparatus, called "nonlinear ultrasonic phased array", based on subharmonic waves and a phased array algorithm. By applying it with large input amplitude (18.8 nm) to closed cracks, both fundamental and subharmonic images indicated the crack tip. On the other hand, when the input amplitude was 8.5 nm, crack tip was observed only in subharmonic image. Thus, the latter provides us to readily judge the crack tip to be closed. To optimize input amplitude, we examined input-amplitude dependence of the intensity at crack tip in fundamental and subharmonic images. Also, in theoretical analysis, we constructed an elastic body-oscillator model, and compared the input-amplitude dependence of calculated fundamental and subharmonic components in reflected waves with the experimental results.
超音波エレクトロニクスの基礎と応用に関するシンポジウム運営委員会の論文
2006-11-15