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Machida, Hideo*; Koizumi, Yu*; Wakai, Takashi; Takahashi, Koji*
Nihon Kikai Gakkai M&M 2019 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), p.OS1307_1 - OS1307_5, 2019/11
This paper describes the fracture test and fracture analysis of a pipe under displacement control load. In order to grasp the fracture behavior of the circumferential through-wall cracked pipe, which is important in evaluating the feasibility of leak before break (LBB) in sodium cooled reactor piping, a fracture test in case of a circumferential throughwall crack in the weld line between an elbow and a straight pipe was carried out. From this test, it was found that no pipe fracture occurs in the displacement control loading condition even if a large circumferential through-wall crack (180
) was assumed. The fracture analysis of the pipe was carried out using Gurson's parameters set based on the tensile test results of the tested pipe material. The analytic results agree well with the test results, and it was found that it will be possible to predict the fracture behavior of sodium cooled reactor piping.
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.
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.
Tsuru, Tomohito
no journal, ,
Recently, some specific highly concentrated solid solution alloys such as gum metals and high-entropy found to have an excellent mechanical property. The origin of these feature cannot be understood well by conventional strengthening mechanism. Here, we propose a new mechanical theory based on local freedom of dislocation core to capture these unique deformation properties.
Tsukimori, Kazuyuki*; Yada, Hiroki; Jin, C.*; Usui, Yoshiya*; Izumi, Yuki*
no journal, ,
In FBR plants the head plate constitutes a part of the boundary of the containment vessel (CV), therefore, it is a very important issue if the function as the boundary is maintained or not in the case of severe accident (SA). Buckling and post-buckling behaviors due to pressure loading must be affected by the thickness distribution of the head plate during press forming process. In this paper non-linear finite element simulation analyses assuming press forming process of a head plate are conducted and the discussion is made comparing the analysis results with the measured results of thickness distribution of the head plate specimen used for the pressure endurance test. And also, the modelling for finite element analyses of head plates is discussed. This time as the first step, axisymmetric analyses are implemented focused on the thickness distribution along the meridional direction of the head plate.