Acoustic emission measurements during cyclic fatigue of welded A533B plates containing defects
A series of A533B specimens, containing realistic intentional weld fabrication defects, has been prepared and fatigue tested in the laboratory under conditions chosen to simulate those on the experimental Ispra pressure vessel. The defects have been validated by radiographic and ultrasonic NDT. Acoustic emission has been recorded during the fatigue of these specimens under carefully controlled testing and monitoring conditions. The unique high bandwidth AEA Technology system has been used in conjunction with new 3-D software to locate the emission events from the defects, and thereby map out their growth. New source characterisation analysis software has been used to distinguish between primary (crack advance) events and secondary events during fatigue. The study has shown conclusively that during the dry fatigue of A533B steel weldments, the acoustic emission activity is dominated by secondary events associated with crack-face fretting, sticking and unsticking. The study has also shown that there are very few primary events of sufficient amplitude to be detected, located and characterised, and that those which were recorded were concentrated in the early stage of fatigue, when the defect was beginning to grow. The results carry important implications for the application of AE to nuclear pressure vessel surveillance, in terms of both the paucity of primary emission events - raising questions about the reliability of the technique for the early detection of critical defects - and the relative abundance of secondary emission events - which can be of great value for the monitoring of known defects.
Bibliographic Reference: EUR 12845 EN (1990) 40 pp., FS, ECU 5
ISBN: ISBN 92-826-1473-5
Record Number: 199011342 / Last updated on: 1994-12-01
Original language: en
Available languages: en