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Journal Articles

Development of the buckling evaluation method for large scale vessels in fast reactors by the testing of Grade 91 steel and austenitic stainless steel vessels subjected to horizontal and cyclic vertical loading

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Ando, Masanori; Okajima, Satoshi

Proceedings of ASME 2023 Pressure Vessels and Piping Conference (PVP 2023) (Internet), 8 Pages, 2023/07

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors to cope with thinning due to increasing diameter and application to the seismic isolation design against huge seismic ground motion. In this study, in order to confirm the applicability of the proposal evaluation method, several buckling tests and FE analyses were carried out using the specimens made of Gr.91 and austenitic stainless steel. The buckling modes and strength data in the load region where the interaction of cyclic axial compression, bending and shear buckling could occur were examined. As a result, it was confirmed that the proposal evaluation method estimated the buckling load in the tests conservatively.

Journal Articles

Development of the buckling evaluation method for large scale vessel in fast reactors by the testing of austenitic stainless steel vessel with severe initial imperfection subjected to horizontal and vertical loading

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Ando, Masanori; Okajima, Satoshi

Proceedings of ASME 2022 Pressure Vessels and Piping Conference (PVP 2022) (Internet), 9 Pages, 2022/07

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors to cope with thinning due to increasing diameter and application to the seismic isolation design against huge seismic ground motion. In this study, in order to confirm the applicability of the proposal evaluation method, several buckling tests and FE analyses were carried out using the specimens made of austenitic stainless steel. The buckling modes and strength data in the load region where the interaction of cyclic axial compression, bending and shear buckling could occur were examined. As a result, it was confirmed that the proposal evaluation method estimated the buckling load in the tests conservatively. Moreover, a series of finite element analyzes to confirm the applicability of the evaluation method in 2.25Cr-1Mo steel and up to 650 $$^{circ}$$C were conducted.

Journal Articles

Development of the buckling evaluation method for large scale vessel by the testing of Gr.91 vessel subjected to horizontal and cyclic vertical loading

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Ando, Masanori; Miyazaki, Masashi

Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 9 Pages, 2021/07

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors to cope with thinning due to increasing diameter and application to the seismic isolation design against huge seismic ground motion. In this study, in order to confirm the applicability of the proposal evaluation method, several buckling tests and FE analyses were carried out using the specimens made of Modified 9Cr-1Mo steel. The buckling modes and strength data in the load region where the interaction of cyclic axial compression, bending and shear buckling could occur were examined. As a result, it was confirmed that the proposal evaluation method estimated the buckling load in the tests conservatively. Moreover, a series of finite element analyzes using a model with residual stress due to welding revealed that the effect of residual stress on buckling strength is negligible in the evaluation method.

Journal Articles

Development of the buckling evaluation method for large scale vessel by the testing of Gr.91 vessel subjected to vertical and horizontal loading

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Ando, Masanori; Miyazaki, Masashi

Proceedings of ASME 2020 Pressure Vessels and Piping Conference (PVP 2020) (Internet), 9 Pages, 2020/08

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors to cope with thinning due to increasing diameter and application to the seismic isolation design against huge seismic ground motion. In this study, in order to confirm the applicability of the proposal evaluation method, several buckling tests and FE analyses were carried out using the specimens made of Modified 9Cr-1Mo steel. The buckling modes and strength data in the load region where the interaction of axial compression, bending and shear buckling could occur were examined. As a result, it was confirmed that the proposal evaluation method estimated the buckling load in the tests conservatively. In addition, buckling strength evaluated by elasto-plastic buckling analysis had good accuracy compared to each test result by considering the stress-strain relationship and imperfection of test specimen.

Journal Articles

Study on the seismic buckling evaluation method for Mod. 9Cr-1Mo steel cylindrical vessel

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Kubo, Koji*; Sato, Kenichiro*; Wakai, Takashi; Shimomura, Kenta

Nihon Kikai Gakkai M&M 2017 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), p.591 - 595, 2017/10

no abstracts in English

Oral presentation

Conceptual design study and related R&Ds toward the demonstration reactor of JSFR, 5; Development of steel plate reinforced concrete containment vessel for JSFR

Kato, Atsushi; Negishi, Kazuo; Sato, Kenichiro*; Akiyama, Yo*; Hara, Hiroyuki*; Iwasaki, Mikinori*; Abe, Ganji*; Tokiyoshi, Takumi*; Okafuji, Takashi*; Umeki, Katsuhiko*; et al.

no journal, , 

Report research and development activities related to steel plate reinforced concrete containment vessel for the JSFR conducted as a part of METI commissioned research.

Oral presentation

Development of steel plate reinforced concrete containment vessel for JSFR, 1; Project summary of SCCV research and development

Kato, Atsushi; Negishi, Kazuo; Akiyama, Yo*; Iwasaki, Mikinori*; Okafuji, Takashi*; Abe, Ganji*; Somaki, Takahiro*; Umeki, Katsuhiko*; Fukushima, Yasuaki*; Sawamoto, Yoshikazu*

no journal, , 

Steel plate reinforced concrete structure are adopted as the JSFR containment vessel to shorten a construction period. This reports project summary of SCCV Research and Development.

Oral presentation

Development of steel plate reinforced concrete containment vessel for JSFR, 3; Analysis method of SCCV barrier function

Kato, Atsushi; Negishi, Kazuo; Akiyama, Yo*; Iwasaki, Mikinori*; Abe, Ganji*; Okafuji, Takashi*

no journal, , 

Steel plate reinforced concrete structure are adopted as the JSFR containment vessel to shorten a construction period. This reports analysis method of SCCV barrier function.

Oral presentation

Oral presentation

Study of steel plate reinforced concrete containment vessel for JSFR, 2; Analysis method of SCCV barrier function, 2

Negishi, Kazuo; Akiyama, Yo*; Okafuji, Takashi*; Abe, Ganji*

no journal, , 

The JSFR adopts SCCV for the quality improvement and reduction of construction term. For commercialization of JSFR, we have carried out the research and development of not only the study on SCCV structure and construction term at the site but also the material strength test and analysis. These series presentation show the results. In this presentation, the results of analysis for SCCV boundary function checkup are shown.

Oral presentation

Buckling evaluation method of Mod. 9Cr-1Mo steel cylinder under horizontal and vertical loads, 2; Effects of cyclic loading and interactions of axial, bending, and shear buckling

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Ando, Masanori; Miyazaki, Masashi

no journal, , 

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors to cope with thinning due to increasing diameter and application to the seismic isolation design against huge seismic ground motion. In this study, in order to cnfirm the applicability of the proposal evaluation method, several buckling tests and FE analyses were carried out using the specimens made of Modified 9Cr-1Mo steel. The buckling modes and strength data in the load region where the interaction of axial compression, bending and shear buckling could occur were examined. As a result, it was confirmed that the proposal evaluation method estimated the buckling load in the tests conservatively. In addition, buckling strength evaluated by elasto-plastic buckling analysis had good accuracy compared to each test result by considering the stress-strain relationship and imperfection of test specimen.

Oral presentation

Buckling evaluation method of Mod. 9Cr-1Mo steel cylinder under horizontal and vertical loads, 1; Effects of material properties and initial imperfection

Miura, Kazuhiro*; Okafuji, Takashi*; Sago, Hiromi*; Shimomura, Kenta; Okajima, Satoshi; Sato, Kenichiro*

no journal, , 

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors in order to cope with thinning due to the increase in diameter, adoption of new materials, and adoption of seismic isolation design due to the increase in the standard seismic ground motion. Buckling evaluation methods corresponding to the above are being considered in the fast reactor standards of the Japan Society of Mechanical Engineers. In this study, in order to examine the applicability of the proposed buckling evaluation equation, Monte Carlo simulation was carried out using material properties and initial imperfections, which are the fluctuation factors of buckling strength, as parameters, and the effect of the fluctuation of these factors on buckling load was evaluated. When the buckling load was normalized by the buckling critical value according to the proposed formula using the longitudinal elastic modulus and the design yield stress of JSME S NC2-2013, the 95% lower confidence limit exceeded the threshold of the proposed formula for both the vertical single load condition and the horizontal and vertical combined load condition. The results show that the buckling critical value calculated by using the design yield stress in the proposed equation is more conservative than the 95% lower confidence limit of the actual buckling load affected by the scatter of material properties and others.

Oral presentation

Study on the effect of initial imperfection shape on buckling strength of cylindrical vessel under the horizontal and vertical loads

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Ando, Masanori; Miyazaki, Masashi

no journal, , 

Buckling evaluation methods capable of evaluating elasto-plastic buckling under axial compression, bending, and shear loads are required for cylindrical vessels of fast reactors to cope with thinning due to increasing diameter and application to the seismic isolation design against huge seismic ground motion. In this study, the effect of initial imperfection and stress of large vessels manufactured by welding multiple plates on the buckling load was evaluated via a series of analyses. In these analyses, the superimposition of global imperfection over the entire vessel due to accumulation of misalignment in buckling mode imperfection had minimal effect on the buckling load. Accordingly, the length for measuring the imperfection amplitude should correspond to the wavelength of the buckling mode. The local imperfection and residual stress by welding also exerted small effects on the buckling load.

Oral presentation

Development of design support tools (Automatic and optimized design of the expansion tank)

Yokoi, Shinobu*; Okafuji, Takashi*; Onoda, Yuichi; Tanaka, Masaaki

no journal, , 

no abstracts in English

Oral presentation

Impact resistance evaluation for CDA in a pool type reactor with common specifications

Eto, Masao*; Yokoi, Shinobu*; Yamashita, Masato*; Miura, Kazuhiro*; Okafuji, Takashi*; Onoda, Yuichi; Yamamoto, Tomohiko; Uchita, Masato*

no journal, , 

no abstracts in English

15 (Records 1-15 displayed on this page)
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