Interval of Observation Plane in Visualization of Region near Defects in Billets Using Ultrasonic Computerized Tomography Method

Abstract

We performed defect detection simulation considering billets with a deep-hole or spherical defect. We conducted defect detection in a billet of duralumin with a deep-hole defect and found no discrepancy between our previous and present research results because the images obtained are similar. We also conducted defect detection in a billet of steel with a spherical defect. We obtained visualization images in multiple measurement planes. We also obtained three-dimensional visualization images by binarizing the pseudo sound velocity. From the images, we found that the three-dimensional visualization of spherical defects is possible and that the scanning pitch in the longitudinal direction is about 10 mm at maximum.

Detection of fish passing through a narrow path using reflected and transmitted ultrasonic waves

“…In the field of nondestructive inspection using ultrasound, increases in the TOFs of transmitted waves caused by diffraction at voids in steel have been observed, even in transmitted waves with shorter wavelengths than the size of the voids. [35][36][37][38][39] Therefore, there is a possibility that the deviations in the ΔTOFs in the transmitted waves around the swim bladder were caused by diffraction, although the swim bladder is a few centimeters 11) and the wavelength of the transmitted ultrasound in the fish body is a few millimeters. These profiles of transmitted waves through a fish body show different characteristics from the profiles of the echoes from fish.…”

“…In addition, waves transmitted through the fish body have not been explored, although transmitted waves have been used for nondestructive inspection. [35][36][37][38][39] For the measurement of fish behavior using a small number of transducers rather than acoustic cameras, it is necessary to extract many features from the ultrasonic signals from each part of the fish body. Here, we investigated the properties of echoes and transmitted waves from a fish body, from the tail to the head, to construct a fish detection method with a simple measurement structure in a narrow path.…”

Transmission detection of internal defects in billets using shear ultrasonic waves

“…It is known that when there is a defect near the propagation path, the reflected wave whose phase is inverted from the defect is included in the received signal, resulting in an apparent decrease in TOF. 30) Thus TOF deviation can detect defects inside the billet. In research using the TOF method, transducers capable of transmitting and receiving longitudinal waves have been used because the propagation speed of longitudinal waves is the fastest among ultrasonic waves propagating inside solids.…”

Compressive sampling–based ultrasonic computerized tomography technique for damage detection in concrete-filled steel tube in a bridge

“…In the measurement phase, a random Bernoulli matrix F is proposed to randomly choose the paths from the equal-spaced measurement net used in the traditional UCT technique. As shown in equation (8), a random matrix containing only 0 and 1 is employed for the decision making of selecting measuring paths from the original net. The size of the matrix is m 3 N representing selecting m measurements from N paths, and m should be larger than the required number mentioned in previous section.…”

“…Jiang et al 7 applied UCT technique in the concrete-filled steel tube (CFST) of underground structures and got accurate inspected results. Kakuma et al 8 used UCT method to visualize the defects in billets. Rahiman et al 9 developed the ultrasonic tomography for imaging liquid and gas flow using a hybrid-binary reconstruction algorithm.…”