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Higa, Ryota*; Fujihara, Hiro*; Toda, Hiroyuki*; Kobayashi, Masakazu*; Ebihara, Kenichi; Takeuchi, Akihisa*
Materials Transactions, 65(8), p.899 - 906, 2024/08
Times Cited Count：3 Percentile：20.18(Materials Science, Multidisciplinary)It is indispensable to suppress hydrogen embrittlement (HE) to develop the strength of the Al-Zn-Mg alloy. Because intergranular fracture (IGF) is mainly observed when HE occurs in the alloy, we need to understand the IGF initiation to suppress HE. In the present study, we investigated the stress, strain, and H concentration, which influence the IGF initiation, in actual fractured regions by simulation of a crystal plasticity finite element method and H diffusion analysis in a 3D image-based model, which was created based on 3D polycrystalline microstructure data obtained from X-ray imaging technique. Combining the simulation and in-situ observation of the tensile test sample by X-ray CT, we examined the stress, strain, and H concentration, and discussed the IG crack initiation condition. As a result, it is revealed that stress normal to grain boundary induced by crystal plasticity dominates IG crack initiation while the accumulation of H due to stress has little impact on it.
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kato, Daisuke*
International Journal of Pressure Vessels and Piping, 81(9), p.749 - 756, 2004/09
Times Cited Count：5 Percentile：33.06(Engineering, Multidisciplinary)The paper describes the procedure to evaluate the ductile crack extension, where an increase in fracture resistance by a ductile crack extension is considered. Two standard 
-resistance curves are prepared for applying the elasto-plastic fracture criterion. Case studies concerning the effect of elasto-plastic fracture criterion were carried out using a severe PTS transient. The introduction of the elasto-plastic fracture criterion significantly contributes to remove the over-conservatism in applying the linear elastic fracture criterion. It was also found that the algorithm of the re-evaluation of crack tip characterization also has a significant effect on the failure probability.
Ugachi, Hirokazu; Tsukada, Takashi; Matsui, Yoshinori; Kaji, Yoshiyuki; Tsuji, Hirokazu; Nagata, Nobuaki*; Dozaki, Koji*; Takiguchi, Hideki*
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 5 Pages, 2003/04
Irradiation assisted stress corrosion cracking (IASCC) is caused by the synergistic effects of neutron irradiation, stress and corrosion by high temperature water. It is, therefore, essential to perform in-pile SCC tests, which are material tests under the conditions simulating those of actual LWR operation, in order to clarify the precise mechanism of the phenomenon, though mainly out-of-pile SCC tests for irradiated materials have been carried out in this research field. This paper will describe the current status of the development of several techniques for in-pile SCC initiation tests in JMTR.
Shibata, Katsuyuki; Kato, Daisuke*; Li, Y.*
Nuclear Engineering and Design, 208(1), p.1 - 13, 2001/08
Times Cited Count：21 Percentile：78.86(Nuclear Science & Technology)no abstracts in English
Shibata, Katsuyuki; Kato, Daisuke*; Li, Y.*
Emerging Technologies: Risk Assessment, Computational Mechanics and Advanced Engineering Topics (PVP-Vol.400), p.49 - 54, 2000/00
no abstracts in English
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Nihon Kikai Gakkai Rombunshu, A, 52(477), p.1228 - 1231, 1986/00
no abstracts in English
