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Ichihara, Yoshitaka*; Nakamura, Naohiro*; Moritani, Hiroshi*; Horiguchi, Tomohiro*; Choi, B.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 21(1), p.1 - 14, 2022/03
In this study, we aim to approximately evaluate the effect of nonlinearity of reinforced concrete structures through seismic response analysis using the equivalent linear analysis method. A simulation analysis was performed for the ultimate response test of the shear wall of the reactor building used in an international competition by OECD/NEA in 1996. The equivalent stiffness and damping of the shear wall were obtained from the trilinear skeleton curves proposed by the Japan Electric Association and the hysteresis curves proposed by Cheng et al. The dominant frequency, maximum acceleration response, maximum displacement response, inertia force-displacement relationship, and acceleration response spectra of the top slab could be simulated well up to a shear strain of approximately 
=2.0
10
. The equivalent linear analysis used herein underestimates the maximum displacement response at the time of ultimate fracture of approximately =4.010. Moreover, the maximum shear strain of the shear wall could not capture the locally occurring shear strain compared with that of the nonlinear analysis. Therefore, when employing this method to evaluate the maximum shear strain and test results, including those during the sudden increase in displacement immediately before the fracture, sufficient attention must be paid to its applicability.
Hirota, Noriaki; Shibata, Hiroshi; Takeuchi, Tomoaki; Otsuka, Noriaki; Tsuchiya, Kunihiko
Journal of Nuclear Science and Technology, 57(12), p.1276 - 1286, 2020/12
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The influence of materials of mineral-insulated (MI) cables on their electrical characteristics upon exposure to high-temperature conditions was examined via a transmission test, in the objective of achieving the stability of the potential distribution along the cable length. Occurrence of a voltage drop along the cable was confirmed for aluminum oxide (Al
O
) and magnesium oxide (MgO), as insulating materials of the MI cable. A finite-element method (FEM)-based analysis was performed to evaluate the leakage in the potentials, which was found at the terminal end. Voltage drop yields by the transmission test and the analysis were in good agreement for the MI cable of AlO and MgO materials, which suggests the reproducibility of the magnitude relationship of the experimental results via the FEM analysis. To suppress the voltage drop, the same FEM analysis was conducted, the diameter of the core wires (
) and the distance between them (
) were varied. Considering the variation of , the potential distribution in the MI cable produced a minimum voltage drop corresponding to a ratio 
of 0.35, obtained by dividing with that of the insulating material (
). In case of varying , a minimum voltage drop was l/ of 0.5.
Sugita, Yutaka; Taniguchi, Naoki; Makino, Hitoshi; Kanamaru, Shinichiro*; Okumura, Taisei*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 19(3), p.121 - 135, 2020/09
A series of structural analysis of disposal containers for direct disposal of spent fuel was carried out to provide preliminary estimates of the required pressure resistance thickness of the disposal container. Disposal containers were designed to contain either 2, 3 or 4 spent fuel assemblies in linear, triangular or square arrangements, respectively. The required pressure resistance thickness was evaluated using separation distance of the housing space for each spent fuel assembly as a key model parameter to obtain the required thickness of the body and then the lid of the disposal container. This work also provides additional analytical technical knowledge, such as the validity of the setting of the stress evaluation line and the effect of the model length on the analysis. These can then be referred to and used again in the future as a basis for conducting similar evaluations under different conditions or proceeding with more detailed evaluations.
Nakajima, Norihiro; Nishida, Akemi; Miyamura, Hiroko; Iigaki, Kazuhiko; Sawa, Kazuhiro
Kashika Joho Gakkai-Shi (USB Flash Drive), 36(Suppl.2), 4 Pages, 2016/10
Since nuclear power plants have dimensions approximately 100m
and their structures are an assembly made up of over 10 million components, it is not convenient to experimentally analyze its behavior under strong loads of earthquakes, due to the complexity and hugeness of plants. The proposed system performs numerical simulations to evaluate the behaviors of an assembly like a nuclear facility. The paper discusses how to carry out visual analysis for assembly such as nuclear power plants. In a result discussion, a numerical experiment was carried out with a numerical model of High Temperature engineering Test Reactor of Japan Atomic Energy Agency and its result was compared with observed data. A good corresponding among them was obtained as a structural analysis of an assembly by using visualization. As a conclusion, a visual analytics methodology for assembly is discussed.
Nakajima, Norihiro; Nishida, Akemi; Kawakami, Yoshiaki; Suzuki, Yoshio; Sawa, Kazuhiro; Iigaki, Kazuhiko
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 5 Pages, 2015/05
A numerical analysis controlling and managing system is implemented on K, which controls the modelling process and data treating, although the manager only controls a structural analysis by finite element method. The modeling process is described by the list of function ID and its procedures in a data base. The manager executes the process by order in the list for simulation procedures. The manager controls the intention of an analysis by changing the analytical process one to another. Experiments were carried out with static and dynamic analyses.
Tian, R.; Nakajima, Norihiro; Yagawa, Genki
Keisan Kogaku Koenkai Rombunshu, 10(1), p.393 - 396, 2005/05
A known problem of partition of unity-based generalized finite element methods (referred to as GFEM) is the linear dependence problem, which leads to singular global (stiffness) matrices. Thus far, attempts to eliminate the linear dependence problem have been unsuccessful. Numerical experiments are carried out among several GFEMs to investigate the problem. Based on the numerical experiments, simple but effective approaches to eliminating the linear dependence problem are suggested.
and YVO laser crystalsSugiyama, Akira; Nara, Yasunaga
Ceramics International, 31(8), p.1085 - 1090, 2005/00
Times Cited Count：18 Percentile：78.81(Materials Science, Ceramics)We succeeded in the fabrication of bonded laser crystals composed of a neodymium-doped YVO laser crystal (Nd:YVO) and its host crystals YVO by a newly developed dry etching technique using an argon ion beam. The optical distortion caused by the bonded interface of size 5 mm 6 mm was estimated to be 0.05-wave at 633 nm. From the comparison of laser performance pumped by a laser diode, the bonded crystals could increase the laser output power by nearly twice that of the non-bonded crystals with the same degree of polarization of 99.2 %. To analyze the mechanism of the enhanced reduction of the thermal load in the bonded crystals, numerical simulations with a finite-element method were also performed.
Tobita, Masahiro*; Matsui, Yoshinori
JAERI-Tech 2003-042, 132 Pages, 2003/03
JAERI-Tech-2003-042.pdf:7.19MB
Prediction of irradiation temperature is one of the important issues in the design of the capsule for irradiation test. Many kinds of capsules with complex structure have been designed for recent irradiation requests, and three-dimensional (3D) temperature calculation becomes inevitable for the evaluation of irradiation temperature. For such 3D calculation, however, many works are usually needed for input data preparation, and a lot of time and resources are necessary for parametric studies in the design. To improve such situation, JAERI introduced 3D-FEM (finite element method) code NISA (Numerically Integrated elements for System Analysis) and developed several subprograms, which enabled to support input preparation works in the capsule design. The 3D temperature calculation of the capsule are able to carried out in much easier way by the help of the subprograms, and specific features in the irradiation tests such as non-uniform gamma heating in the capsule, becomes to be considered.
Yamada, Reiji; Igawa, Naoki; Taguchi, Tomitsugu; Jitsukawa, Shiro
Journal of Nuclear Materials, 307-311(Part2), p.1215 - 1220, 2002/12
Times Cited Count：24 Percentile：80.63(Materials Science, Multidisciplinary)SiC fiber-reinforced SiC composites (SiC/SiC) are considered an advanced structural material for blanket modules of a fusion reactor, which requires high thermal conductivity in order to keep thermal stresses in the material lower than the allowable design stress. The sintered SiC fiber recently developed has obtained high thermal conductivity, so it is highly expected that sintered SiC fiber-reinforced SiC/SiC composites would also show high thermal conductivity. In this study several types of 3D SiC/SiC composites were fabricated by either CVI or PIP method. The results of the thermal conductivity measurements show that the maximum thermal conductivity at room temperature was about 60 W/mK for CVI composites or 25W/mK for PIP ones. These values are considerably higher than those of non-sintered SiC fiber reinforced SiC/SiC composites, which indicates a possibility that the developed materials would be promising. The FEM thremal analysis shows the good agreement between the caluculated and experimental results.
Ishihara, Masahiro; Baba, Shinichi; Takahashi, Tsuneo*; Aihara, Jun; Shibata, Taiju; Hoshiya, Taiji
JAERI-Tech 2002-054, 169 Pages, 2002/07
JAERI-Tech-2002-054.pdf:5.93MB
no abstracts in English
Wakui, Takashi*; Futakawa, Masatoshi; Tanabe, Yuji*; Ioka, Ikuo
Zairyo, 51(6), p.681 - 687, 2002/06
This paper describes the novel technique for determining constants in constitutive equaution of elastic-palstic materials by the indentation test with indenters having different tip angles. FEM analyses were carried out to evaluate the effect of material constants and the indenter tip angle on the load-depth curve. The constitutive equation was determeined from the characterized curves associated with the effects on the slope. Simiulation analyses were performed for some material models to exammine accuracy of the presented technique. It is confirmed that this technique is useful to determine the constitutive equation of sub-surface of materials or coatings.
Tobita, Masahiro*; Matsui, Yoshinori
KAERI/GP-195/2002, p.87 - 95, 2002/00
In the Japan Materials Testing Reactor (JMTR) of Japan Atomic Energy Research Institute (JAERI), the temperature distribution inside of irradiation specimens and capsules structure material are evaluated in the design of irradiation capsules. For the evaluation of detailed temperature distribution, NISA (Numerically Integrated elements for System Analysis) code has been introduced, and subprograms are developed to simplify the input data of the capsules structure and the analysis conditions using the three-dimensional finite element method. By the development of subprograms, prediction of the temperature distribution inside of irradiation specimens and capsules structure material became detailed and more accurate than calculation by one-dimensional code. Also estimation of detail temperature distribution during irradiation became possible based on the indication of thermocouple.
Kikuchi, Kenji; Futakawa, Masatoshi; Ishikura, Shuichi*; Kogawa, Hiroyuki
Nihon Kikai Gakkai Zairyo Rikigaku Bumon Koenkai (M&M'99) Koen Rombunshu, p.467 - 468, 1999/10
no abstracts in English
Ishihara, Masahiro; Baba, Shinichi; Aihara, Jun; Hayashi, Kimio; Arai, Taketoshi; Ishino, Shiori*
Proceedings of 1st Information Exchange Meeting on Basic Studies on High-Temperature Engineering, p.299 - 308, 1999/09
no abstracts in English
Tokuda, Shinji; *
Physics of Plasmas, 6(8), p.3012 - 3026, 1999/08
Times Cited Count：56 Percentile：83.39(Physics, Fluids & Plasmas)no abstracts in English
*; Kaji, Yoshiyuki; *; ; *; Kaburaki, Hideo
Keisan Kogaku Koenkai Rombunshu, 3(1), p.59 - 62, 1998/05
no abstracts in English
Tokuda, Shinji; *
Purazuma, Kaku Yugo Gakkai-Shi, 73(10), p.1141 - 1154, 1997/10
no abstracts in English
Fujimura, Toichiro
JAERI-Data/Code 95-019, 54 Pages, 1996/01
JAERI-Data-Code-95-019.pdf:1.47MB
no abstracts in English
Fujimura, Toichiro
Computer Physics Communications, 82, p.111 - 119, 1994/00
Times Cited Count：1 Percentile：21.58(Computer Science, Interdisciplinary Applications)no abstracts in English
Tokuda, Shinji; *; *
JAERI-M 93-075, 32 Pages, 1993/03
no abstracts in English
