Critical experiments, measurements, and analyses to establish a crack arrest methodology for nuclear pressure vessel steels. Quarterly report, January--March 1977
Static and dynamic, two-dimensional finite difference analyses of the compact (CT) tension specimen are described. The static analyses define the specimen compliance and relation between the displacement of the load point and that existing at the end of the specimen. The dynamic analyses define the relations among the K/sub Q//K/sub ID/-ratio, the crack advance, and the average crack velocity for a wide range of run-arrest events in ordinary- and duplex-CT specimens. Results of instrumented run-arrest experiments in CT-specimens of A533B steel are presented which define relations between crack advance and crack velocity and effects of load train compliance. Load-train compliance measurements reveal that significant amounts of ''excess'' strain energy are stored in the stressed regions of the wedge, pins and specimen adjacent to the contact areas. This ''excess'' energy, which is transmitted to or redistributed within the test specimen while the crack is propagating, arrives too late to affect the average velocity, but does cause the crack to propagate farther. The K/sub ID/-valves inferred from the velocity measurements agree with the fast-fracture-toughness values previously obtained for the same steel from more deeply side grooved DCB-specimens. A formal, ASTM-type specification for a ''Proposed Tentative Method of Test for Fast Fracture Toughness and Crack Arrest Toughness'' is presented. The method employs a dynamic interpretation, but requires no dynamic measurements. A strain gage-based crack velocity measuring technique that can be used at elevated temperatures is evaluated. Finally, four preliminary tests of the ORNL A533B ''quenched'' material that were carried out at 93/sup 0/C and 149/sup 0/C are described. The response of the duplex-specimens appears to be complicated by the formulation of a tough-heat affected zone adjacent to the weld in the test material.
- Research Organization:
- Battelle Columbus Labs., OH (USA)
- OSTI ID:
- 7058685
- Report Number(s):
- NUREG/CR-0079
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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Critical experiments, measurements and analyses to establish a crack arrest methodology for nuclear pressure vessel steels. Task 62. Second annual progress report, 1 July 1975 to 30 June 1976
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