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.

Automatic ultrasonic flaw detection method and apparatus of welded section

Abstract: PROBLEM TO BE SOLVED: To obtain an automatic ultrasonic flaw detection method and an automatic ultrasonic flaw detection apparatus of welded sections for surely detecting flaws and reducing the flaw detection time by combining a pulse reflection method and a TOFD method. SOLUTION: In the automatic ultrasonic flaw detection method of a welded section, the pulse reflection method for performing the vertical square scanning of a probe, in a direction along a welded line and a direction at right angles to the welded line, and the TOFD system for scanning the probe in a direction along the welded line are combined so as to be compound flaw detection. In the automatic ultrasonic flaw detection apparatus of the welded section, a rail is installed in parallel with the welded line, a body that can drive while being guided by the rail is installed, a movable shaft that can slide at right angles to the driving direction of the body, a fixed shaft that is extended in the same direction are provided, a probe for pulse reflection is fitted to the movable shaft, and the probe for TOFD is fitted to the fixed shaft.

Sizing of cracks embedded in sub-cladding using the ultrasonic synthetic aperture focusing technique (SAFT)

Abstract: This paper deals with the experimental work carried out to demonstrate the feasibility of the ultrasonic Synthetic Aperture Focusing Technique (SAFT) to obtain improved detection and sizing of vertical/inclined (10° and 15°) simulated cracks underneath different claddings. Crack heights ranging from 1.68 mm to 19.04 mm underneath stainless steel, Inconel and ferritic steel cladding were sized with an accuracy of ′0.1 to ′0.3 mm. The problems encountered in TOFD with regard to sizing of near-surface cracks was successfully overcome by SAFT. Mis-oriented (inclined) defects embedded below the cladding suffer added disadvantage for ultrasonic detection due to loss of reflected energy due to mis-orientation. Using SAFT even these defects could be sized accurately.

Ultrasonic flaw sizing - an overview

Abstract: The time-of-flight diffraction (TOFD) technique is one of the most common sizing methods in practical use by industry today. This method was developed over 40 years ago and is based on the technology and state of knowledge present at that time. A combination of phased arrays and equivalent flaw sizing methods are proposed as the foundation for a new generation of sizing methods that go beyond TOFD sizing.

Crack defect detection and localization using genetic-based inverse voting Hough transform

Abstract: We propose a genetic-based inverse voting Hough transform (GBIVHT) method to detect buried crack defects in engineering structures. The method is applied to B-scan images obtained according to the ultrasonic time of flight diffraction technique. In these image representations of the ultrasound data, crack defects are characterized by multiple arcs of diffraction that can be approximated by a parabolic model. Thus, the crack defect detection problem in non-destructive inspection of engineering structures is transformed into a parabola detection and localization on B-scan images. In the proposed GBIVHT method, the local peak detection problem of conventional HT is converted into a parameter optimization problem that operates directly on the B-scan images. The optimization task is done using the well-known genetic algorithms. Our main goals are an accurate detection of the parabolas while circumventing the computational complexity and huge storage problem tied to conventional HT.