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Showing papers on "Time-of-flight diffraction ultrasonics published in 1998"


Patent
01 May 1998
TL;DR: In this paper, a TOFD method is used to detect ultrasonic flaws. But, the method is not suitable for the detection of ultrasonic anomalies, and the ultrasonic vibrators are shifted by one by one to generate ultrasonic waves.
Abstract: PROBLEM TO BE SOLVED: To efficiently perform ultrasonic flaw detection by using a TOFD method. SOLUTION: When vertical scanning is performed by a TOFD method, at first, for example, four continuous ultrasonic vibrators 11 1 -11 4 among ultrasonic vibrators provided to an ultrasonic probe 11 are excited to generate ultrasonic waves. In the reception of these ultrasonic waves, four ultrasonic vibrators 12 n -12 n-3 among the ultrasonic vibrators provided to an ultrasonic probe 12 are used. Next, ultrasonic vibrators are shifted by one to generate ultrasonic waves in ultrasonic vibrators 11 2 -11 5 , and these ultrasonic waves are received by ultrasonic vibrators 12 n-1 -12 n-4 . Thereafter, flaw detection is performed while the ultrasonic vibrators are successively shifted one by one, and ultrasonic waves are finally generated by using ultrasonic vibrators 11 n-3 -11 n to be received by ultrasonic vibrators 12 4 -12 1 . COPYRIGHT: (C)1999,JPO

7 citations




Proceedings ArticleDOI
15 Mar 1998
TL;DR: In this article, an application of machine vision applied to the analysis of ultrasonic images formed using the time-of-flight diffraction (TOFD) method on incomplete weld geometries is described.
Abstract: An application of machine vision applied to the analysis of ultrasonic images formed using the time-of-flight diffraction (TOFD) method on incomplete weld geometries is described. The rationale of the work being to identify weld defects as soon as they are produced, thereby reducing the costs of any subsequent repairs. The analysis uses TOFD scans as input to a filtering and 'window' based variance operator for the segmentation of suspect defect areas inside the weld region. A suite of pc based software and a high temperature TOFD data acquisition system have been benchmarked through a series of demonstration trials on both 80mm thick carbon steel submerged arc welded testpieces, and 25mm thick carbon steel tungsten inert gas welded testpieces. The range of intentionally implanted defects, from root cracks to lack of side wall fusion, were detected with an overall accuracy of 79 percent on a data set of 174 defects on scans performed at 10-90 percent weld completion.

1 citations