Topic
Time-of-flight diffraction ultrasonics
About: Time-of-flight diffraction ultrasonics is a research topic. Over the lifetime, 544 publications have been published within this topic receiving 3189 citations.
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Patent•
20 Apr 2017
TL;DR: In this paper, the authors proposed a measuring apparatus and measuring method similar to a TOFD method capable of clearly determining the boundary between a thermal effect region and a non-thermal effect region.
Abstract: PROBLEM TO BE SOLVED: To provide a measuring apparatus and measuring method similar to a TOFD method capable of clearly determining the boundary between a thermal effect region and a non-thermal effect region.SOLUTION: A measuring apparatus for measuring a thermal effect region in a metal specimen includes: an ultrasonic sound generation unit that is disposed on an inspection surface of the metal specimen and generates an ultrasonic sound; an ultrasonic sound receiving unit that is disposed on the inspection surface and outputs a waveform signal of the ultrasonic sound having propagated through the metal specimen; a moving mechanism for moving the ultrasonic sound generation unit and ultrasonic sound receiving unit along the inspection surface; and a display unit for two-dimensionally displaying the waveform signal according to the movement distance of the ultrasonic sound generation unit and ultrasonic sound receiving unit by the moving mechanism.SELECTED DRAWING: Figure 1
01 Jan 2015
TL;DR: In this article, a tethered 10" tool was developed for inspection of circumferential cracks at anode pads welded on the pipes, which can be used with a modified sensor carrier providing similar detection and sizing performance as for axial cracking.
Abstract: Typically inline inspection is carried out for the detection and sizing of geometry defects, corrosion / wall thickness loss and cracking defects. Regarding cracking, most of the time axial cracking (SCC, seam weld cracks....) is observed due to the typical loading condition in pressurized pipes. Since 1994 ultrasonic crack inspection tools are available for the reliable detection of such cracks using conventional ultrasonic shear wave technique. This technique is well suited for detection but has limited depth sizing capabilities as the reflection amplitudes are affected by several other factors apart from depth. Under special conditions (bending forces, poor welding) cracking can also appear in circumferential direction. For this type of cracks, basically the same type of tool can be used with a modified sensor carrier providing similar detection and sizing performance as for axial cracking. In offshore applications, however, accurate sizing in particular of crack depth is an important requirement as offshore verification and repair work is usually very cost-intensive. In order to provide a high POD together with good sizing performance a tethered 10" tool was developed for inspection of circumferential cracks at anode pads welded on the pipes. It contains a pulse - echo (PE) unit for reliable detection and a TOFD (time-of-flight-diffraction) unit for accurate sizing of circumferential cracks. The PE technique is used for fast screening during the forward inspection. The TOFD measurement which is basically stationary is performed on the backward inspection by stopping at every location where a crack indication was detected by the PE inspection. Extensive testing of the new tool was performed at a 10" test pipeline with circumferential cracking at original anode pads. Blind testing took place with 64 artificial weld defects and an unknown number of fatigue cracks at the anode pads which were generated by full scale fatigue testing of the corresponding pipes. After testing the sizes of the fatigue cracks (length, depth) were determined by destructive examination. The comparison of the results from ILI inspection and destructive testing showed that the ILI tethered tool fully met the specification with regard to detection and sizing. After the successful validation the tool was used for a tethered inspection of a 10" offshore pipeline (length 8 km). In the paper the inspection concept and the setup of the new tool will be described. Results from the qualification tests as well as from the first inspection run performed with the new tool will be presented.
Patent•
22 Jul 2016
TL;DR: In this article, an ultrasonic microscopy unit using one or more waveforms including at least one of straight beam, phased array, shear wave, and time-of-flight diffraction (TOFD) was used to detect a texture of a carbon steel material.
Abstract: Embodiments relate generally to systems and methods for determining a toughness value for a material of a metal part, wherein the method comprises detecting a texture of a carbon steel material using an ultrasonic microscopy unit, wherein the ultrasonic microscopy unit uses one or more waveforms including at least one of straight beam, phased array, shear wave, and time-of-flight diffraction (TOFD); determining elemental analysis of the carbon steel material; combining the texture with the elemental analysis to generate a toughness value for the steel; comparing the generated toughness value with a standard curve, wherein when the toughness value falls below the curve, the carbon steel material comprises an acceptable toughness, and when the toughness value falls above the curve, the carbon steel material comprises an unacceptable toughness.
01 Jan 1993
TL;DR: In this article, a tomographic imaging system based on time-off-light diffraction with point-like sources is described for NDT inspections of metal structures, which is particularly suited for metal structures because they are reliable and accurate.
Abstract: Time-of-flight diffraction techniques are particularly suited for NDT inspections of metal structures because they are reliable and accurate. This paper describes a tomographic imaging system based on time-off-light diffraction with point-like sources. The design of efficient point-like sources for standard immersion probes is outlined. Applications of this imaging technique for defect detection and sizing are reported and compared to simulated images.
Journal Article•
TL;DR: In this article, an aluminum sample containing artificial internal crack is inspected by using the method of ultrasonic time of flight diffraction (TOFD), and the low resolution B-scan image with hyperbolic feature is processed in order to improve testing precision.
Abstract: An aluminum sample containing artificial internal crack is inspected by using the method of ultrasonic time of flight diffraction(TOFD),and the low resolution B-scan image with hyperbolic feature is processed in order to improve testing precision.According to the inspection manner of ultrasonic TOFD,a synthetic aperture focusing technique(SAFT)algo- rithmic model for B-scan image reconstruction is founded.By using the model,ultrasonic TOFD B-scan image can be en- hanced.The time resolution of the B-scan image is improved by the pre-processing of searching for gray peak value,and the lateral resolution of the image is enhanced by suppression of the cutter by the following processing of SAFT.A B-scan im- age processing method that based on searching for gray peak value and SAFT is therefore proposed.A processing window is adopted in order to minimize the execution time of the algo- rithm,and proper width of the window is chosen.The result shows that the method can effectively enhance the target in the image,and the location of upper and lower crack tip in the sample can be measured rapidly and accurately accordingly.