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Kuroda, Masatoshi*; Kamaya, Masayuki*; Yamada, Teruaki*; Akita, Koichi
Nihon Kikai Gakkai Rombunshu (Internet), 83(852), p.17-00072_1 - 17-00072_7, 2017/07
In order to assess the fatigue damage of austenitic stainless steels by electron backscatter diffraction (EBSD) method more simply and easily, it should be more preferable to use a commercially available general-purpose EBSD analysis software rather than to employ an in-house developed EBSD analysis programme. In the present study, EBSD measurement was performed for Type 316 austenitic stainless steels subjected to cyclic loading, and the applicability of the EBSD parameter relevant to the pattern quality, which could be obtained by the commercial software, to the fatigue damage assessment was discussed by comparing the other EBSD parameter of the averaged local misorientation (Mave), which could be calculated by the in-house developed programme. As a result, the EBSD parameter relevant to the pattern quality, which signified the full width at half maximum (FWHM) of the histogram distribution of the image quality (IQ), was saturated at the beginning stage of the fatigue cycles, while Mave was increased monotonically with the cycles. This suggested that the FWHM of IQ could be useful to detect the initial stage of the fatigue damage, while Mave was suitable for the quantitative evaluation of the fatigue damage. XRD measurement was also carried out for the same samples employed in the EBSD measurement, and the XRD data was compared with the EBSD data to discuss the crystallographic mechanism of the change in the FWHM of IQ. As a result, it was found that the FWHM of the (111) XRD peak correlated well with the FWHM of IQ. Because the (111) plane in fcc metal such as austenitic stainless steel was most preferable for slip system, this implied that the change in the distribution of the pattern quality generated by the fatigue loading could be due to the slip deformation.
Hojo, Kiminobu*; Hayashi, Shotaro*; Nishi, Wataru*; Kamaya, Masayuki*; Katsuyama, Jinya; Masaki, Koichi*; Nagai, Masaki*; Okamoto, Toshiki*; Takada, Yasukazu*; Yoshimura, Shinobu*
Mechanical Engineering Journal (Internet), 3(4), p.16-00083_1 - 16-00083_16, 2016/08
Performance demonstration certification of non-destructive inspection for cast stainless steel (CASS) has been planned but the target flaw depth to be detected has not been determined yet in Japan. The target flaw size is closely connected to the allowable flaw size which is determined by flaw evaluation of the rules on fitness-for-service. For rational mitigation of the acceptable flaw size, application of probabilistic fracture mechanics (PFM) is one of the useful countermeasures compared with deterministic approach. In this paper, benchmark problems for a CASS pipe were proposed with intention applying and verifying PFM codes. As the fracture modes, fatigue crack extension, plastic collapse and ductile crack initiation were assumed. Six organizations participated in the benchmark analysis and failure probabilities from them were compared. As a result the failure probability of each problem showed good agreement and the code for application of CASS issue has been verified.
Umeda, Koji; Asamori, Koichi; Oikawa, Teruki; Kakuta, Chifumi; Zhao, N.*; Kamaya, Noriko*
Gekkan Chikyu, 26(6), p.407 - 413, 2004/06
None
Tateiwa, Naoyuki*; Hanazono, Katsumi*; Kobayashi, Tatsuo*; Amaya, Kiichi*; Inoue, Tetsutaro*; Kindo, Koichi*; Koike, Yoshihiro; Metoki, Naoto; Haga, Yoshinori; Settai, Rikio*; et al.
Journal of the Physical Society of Japan, 70(10), p.2876 - 2879, 2001/10
Times Cited Count：61 Percentile：86.52(Physics, Multidisciplinary)no abstracts in English
Muramatsu, Toshiharu; Shobu, Takahisa; Amaya, Koichi*; Urushisaki, Yukinori*; Matsubara, Hideto*
no journal, ,
no abstracts in English
Urushisaki, Yukinori*; Amaya, Koichi*; Matsubara, Hideto*; Shobu, Takahisa; Muramatsu, Toshiharu
no journal, ,
no abstracts in English
Shobu, Takahisa; Urushisaki, Yukinori*; Ichimura, Makoto*; Amaya, Koichi*; Yada, Hiroki; Takase, Kazuyuki; Muramatsu, Toshiharu
no journal, ,
no abstracts in English
Yada, Hiroki; Yamada, Tomonori; Muramatsu, Toshiharu; Fukanuma, Hirotaka*; Amaya, Koichi*; Urushisaki, Yukinori*
no journal, ,
no abstracts in English
Kuroda, Masatoshi*; Kamaya, Masayuki*; Akita, Koichi; Yamada, Teruaki*; Shimasaki, Tomonori*; Tanigawa, Ryohei*
no journal, ,
no abstracts in English
Motoyama, Aoi*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Hase, Hideaki*; Koyama, Takao*; Sakanaka, Shinya*; Yamaya, Yusuke*; Aizawa, Koki*; et al.
no journal, ,
no abstracts in English
Motoyama, Aoi*; Ichiki, Masahiro*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Koyama, Takao*; Sakanaka, Shinya*; Hase, Hideaki*; Aizawa, Koki*; et al.
no journal, ,
We compiled the magnetotelluric (MT) and geomagnetic transfer function (GDS) data which were acquired by Uchida (2004), Umeda et al. (2008), Asamori et al. (2011), Uyeshima (private comm.) and Ogawa (private comm). The 118 observation sites locate in the study area. Both MT and GDS frequency response was used to model three-dimensional resistivity distribution of the southern Tohoku district, NE Japan. The resultant resistivity model reveals no conductor beneath the onshore forearc in Fukushima prefecture. The model rather shows resistor there with over several-thousand ohm-m, which corresponds to the Abukuma batholiths. Thus, our model indicates that the area only around Iwaki-city is peculiar forearc, where fluid migrates upward from deep crust.
Usui, Yoshiya*; Ueshima, Makoto*; Hase, Hideaki*; Ichihara, Hiroshi*; Aizawa, Koki*; Koyama, Takao*; Sakanaka, Shinya*; Ogawa, Tsutomu*; Yamaya, Yusuke*; Nishitani, Tadashi*; et al.
no journal, ,
In the back-arc area of the southern Tohoku region, there are several quaternary volcanos and active faults that have the potential to cause M7-class inland earthquakes. In the vicinity of some of the volcanoes, deep low-frequency earthquakes occur, implying the transfer of melt or aqueous fluid. So as to reveal the magma supply system around the area, it is important to reveal the distribution of the subsurface fluid. Also, understanding the fluid distribution helps elucidate the earthquake generation process. To delineate the subsurface electrical resistivity structure, the authors estimated the resistivity structure in the area by performing magnetotelluric surveys and generating the 3-D resistivity structure model with high resolution. In this study, the authors show the resultant electrical resistivity structure and discuss the subsurface fluid distribution as well as its relationship with the volcanic and seismic activities around the study area.
