低周波アレイ探触子を用いたコンクリート内部の鉄筋および 円筒管の高速映像化
High-speed Ultrasonic Imaging of Steel Bars and Pipes in Concrete using Low Frequency Array Transducer
著者:
小澤 耀生 Akio OZAWA 中畑 和之 Kazuyuki NAKAHATA 大平 克己 Katsumi OHIRA 小川 健三 Kenzo OGAWA
発刊日:
公開日:
Array TransducerConcreteFull-waveform Sampling and Processing (FSAP)GPU CalculationInternal Steel Bars and PipesUltrasonic Imaging
概要
The use of ultrasonic arrays for non-destructive testing has been widely spread in recent years. As an array imaging method, we propose the full-waveform sampling and processing (FSAP) technique that utilizes a complete set of signals of all combinations of transmission and reception elements. The ultrasonic beam is synthesized from the signal set by the post-processing with the GPU calculation. In this study, pipes and reinforced steel bars in concrete material were reconstructed with the FSAP. Since the ultrasonic wave attenuates significantly in concrete, we develop an array transducer with a 50 kHz center frequency. For the effective focusing of ultrasonic beam in concrete, the ultrasonic wave field radiated from the array transducer is simulated using the multi-Gaussian beam model. In experimental measurements, it was shown that the shapes of pipes and steel bars in a concrete specimen with 800 mm height were reconstructed with high accuracy in real time.
