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Xiong, Z.*; Naoe, Takashi; Futakawa, Masatoshi
Metals, 9(4), p.412_1 - 412_11, 2019/04
Times Cited Count：8 Percentile：42.13(Materials Science, Multidisciplinary)The effect of surface defects on the very high cycle fatigue (VHCF) behavior were investigated on the solution annealed (SA) and cold-rolled (CW) 316L. Surface defects were artificially created using indentation. VHCF test was conducted using an ultrasonic fatigue method. The results showed that the fatigue crack initiation was independent of the indent with the applied range of depth in this research. Furthermore, the critical depth of the indent was evaluated based on an empirical formula. In the case of SA, the VHCF strength was not affected when the indent depth was less than 40 
m, which is consistent with the value obtained from the empirical formula. In the case of 20% CW, VHCF strength was not affected when the indent depth was less than 80 m. The results were much larger than the results obtained from the empirical formula and might have been caused by the plastic deformation, residual stress and probable deformation induced martensite transition around the indent.
Yamaguchi, Yoshihito; Hasegawa, Kunio; Li, Y.
Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 6 Pages, 2018/07
Crack closure during fatigue crack growth is an important phenomenon for predicting fatigue crack growth amount. Much experimental data shows that fatigue cracks close at not only negative loads but also positive loads during a constant amplitude loading cycle. The Appendix A-4300 in the ASME Code Section XI provides two equations of fatigue crack growth rates expressed by stress intensity factor range for ferritic steels under negative stress ratio. One is the equation taking into account crack closure and the other does not consider the crack closure. The boundary of crack closure is classified by the magnitude of applied stress intensity factor range. The objective of this paper is to investigate the influence of the magnitude of stress intensity factor range on crack closure. Fatigue tests have been performed on ferritic steel in air environment at room and high temperatures. Crack closures were obtained as a parameter of stress ratio. It was found that crack closure occurs more small applied stress intensity factor range than the definition given by the Appendix A-4300.
Yamaguchi, Yoshihito; Katsuyama, Jinya; Li, Y.
Yosetsu Kozo Shimpojiumu 2017 Koen Rombunshu, p.21 - 27, 2017/12
no abstracts in English
Nishi, Hiroshi; Eto, Motokuni; Tachibana, Katsumi; Koizumi, Koichi; Nakahira, Masataka; Takahashi, Hiroyuki*
Fusion Engineering and Design, 58-59, p.869 - 873, 2001/11
Times Cited Count：2 Percentile：19.6(Nuclear Science & Technology)no abstracts in English
Nishi, Hiroshi; Eto, Motokuni; Tachibana, Katsumi; Nakahira, Masataka
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
Fatigue test of the weldments was performed to investigate their fatigue behavior and the effect of the incomplete penetrations on the fatigue strength. Fatigue crack propagation test of their weld metals was also carried out using CT specimen. By calculating stress intensity factors of the weldments contained the incomplete penetrations and cracks using FEM analysis, the fatigue crack propagation rates of weldments were evaluated and compared those of their weld metals. Fatigue life of the weldments was evaluated based on fracture mechanics to discuss the effect of incomplete penetrations on the fatigue strength. As the results, the incomplete penetration behaved as a crack and most of total fatigue life for the weldment was crack propagation life. The crack propagation rates of weldment were in accordance with those of the weld metals. The fatigue strength of the weldment was considerably lower than that of smoothed specimen. The incomplete penetrations affected greatly the fatigue strength of the weldments even if the depth of incomplete penetrations was small.
Motooka, Takafumi; Kiuchi, Kiyoshi
JAERI-Research 99-039, 14 Pages, 1999/05
JAERI-Research-99-039.pdf:2.03MB
no abstracts in English
*; *; *; Hatano, Toshihisa
Fusion Technology 1998, 1, p.177 - 180, 1998/00
no abstracts in English
RIST News, 00(22), p.3 - 49, 1996/00
no abstracts in English
Tsuji, Hirokazu; *; Tsukada, Takashi; Nakajima, Hajime
Journal of Nuclear Science and Technology, 30(12), p.1234 - 1242, 1993/12
Times Cited Count：3 Percentile：38.1(Nuclear Science & Technology)no abstracts in English
Tsuji, Hirokazu; *; Tsukada, Takashi; Nakajima, Hajime
JAERI-M 93-204, 24 Pages, 1993/10
no abstracts in English
Tsuji, Hirokazu; *; Tsukada, Takashi; Nakajima, Hajime
Proc. of the 4th Int. Symp. on Advanced Nuclear Energy Research (JAERI-CONF 1/JAERI-M 92-207), p.426 - 433, 1992/12
no abstracts in English
K control modes on variability/reproducibility of fatigue crack growth rate dataTsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo
Journal of Nuclear Materials, 189, p.65 - 71, 1992/00
Times Cited Count：4 Percentile：41.92(Materials Science, Multidisciplinary)no abstracts in English
*; Tsukada, Takashi; Nakajima, Hajime
JAERI-M 90-237, 103 Pages, 1991/01
no abstracts in English
;
Nihon Genshiryoku Gakkai-Shi, 30(2), p.181 - 192, 1988/02
Times Cited Count：2 Percentile：31.31(Nuclear Science & Technology)no abstracts in English
JAERI-M 84-122, 124 Pages, 1984/07
no abstracts in English
; *; *
JAERI-M 82-149, 30 Pages, 1982/10
no abstracts in English
;
JAERI-M 82-049, 27 Pages, 1982/05
no abstracts in English
Nakajima, Hajime; *; *; *; Shindo, Masami
ASTM Special Technical Publication 738, p.139 - 160, 1981/00
no abstracts in English
; ; *
JAERI-M 8900, 75 Pages, 1980/06
no abstracts in English
Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Wakai, Eiichi; Takada, Hiroshi
no journal, ,
At the Japan Spallation Neutron Source (JSNS), there was trouble twice at the water shroud of the mercury target due to the thermal stress during operating periods with proton beam power at 500 kW in 2015. The target vessel, made from 316L stainless steel, has a triple-walled structure consisting of mercury vessel, inner and outer water shrouds, where the interstitial space between the mercury vessel and the water shroud is filled with helium gas. For the first trouble, the leak was to the outside of the shroud and the location was specified at a welded portion around a bolt connection. For the second trouble, the leak was detected in the helium layer. Results of FEM simulations suggested that the location was susceptible to fatigue cracking due to the cyclic thermal stress induced by beam trips. The cause of the troubles was attributed to the complicated structural design in which incompleteness remained at welding. The next target vessel design was improved to reduce welding lines ca. 30% and bolt connection as much as possible.
