Fracture mechanics analysis of cast duplex stainless steel elbows containing a surface crack
- Electricite De France, Moret S/Loing (France)
- Electricite De France (EDF), Villeurbanne (France)
EDF, in cooperation with the French Atomic Energy Commission (CEA) and Framatome, has conducted a research program on the fracture behavior of aged cast duplex stainless steel elbows. The main task of this program consisted in testing two large diameter aged cast elbows under in-plane closure bending at 420 C. This paper, after a short presentation of the experimental results, presents the ductile fracture analyses performed. Both elbows contained a semi-elliptical notch machined on the outer surface of one flank, oriented either in the longitudinal direction (first test) or in the circumferential one (second test). The crack was submitted to tensile stresses, so it may initiate and subsequently grow by ductile tearing. Despite the low toughness of the steel, the crack extension remained stable up to the end of the tests, the final crack extension reaching 8 mm (first test) and 13 mm (second one). The test analyses were performed using elastic-plastic finite element calculations, with a model built up with 20-node elements and containing about 12,000 nodes. Due to the importance of the ovalization phenomenon in the elbows, the calculations were made under the large deformation hypothesis, requiring the development of a new formulation for the energy release rate parameter G. The first purpose of these calculations was to show their ability to simulate accurately the tests, by comparison with the measurements. The second purpose was to conduct a crack growth analysis by comparing calculated J curves (accounting for different crack depths) to the material J-R curve obtained on CT specimens. The accuracy of this type of analysis is satisfactory, considering the scatter of the J material data.
- OSTI ID:
- 403214
- Report Number(s):
- CONF-960706-; ISBN 0-7918-1770-9; TRN: 97:000169
- Resource Relation:
- Conference: American Society of Mechanical Engineers (ASME) pressure vessels and piping conference, Montreal (Canada), 21-26 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Fatigue and fracture -- 1996: Volume 1. PVP-Volume 323; Mehta, H.S. [ed.] [GE Nuclear Energy, San Jose, CA (United States)]; Bhandari, S. [ed.] [Framatome, Paris (France)]; Jones, D. [ed.] [Westinghouse Bettis, Pittsburgh, PA (United States)]; Rahman, S. [ed.] [Univ. of Iowa, Iowa City, IA (United States)]; Wilkowski, G. [ed.] [Battelle, Columbus, OH (United States)]; Yoon, K.K. [ed.] [Framatome Technologies, Lynchburg, VA (United States)]; PB: 412 p.
- Country of Publication:
- United States
- Language:
- English
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