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Mano, Akihiro; Imai, Ryuta*; Miyamoto, Yuhei*; Lu, K.; Katsuyama, Jinya; Li, Y.
International Journal of Pressure Vessels and Piping, 199, p.104700_1 - 104700_13, 2022/10
Times Cited Count:0 Percentile:30(Engineering, Multidisciplinary)Elastic-plastic analyses based on finite element methods are widely applied to simulate the nonlinear behaviors of materials. When the analysis is conducted by an implicit method, the stress values are generally updated with a time increment by using the so-called return mapping algorithm. This algorithm requires solving simultaneous nonlinear equations related to a constitutive model. In the present paper, we proposed a general method to reduce the number of equations in the return mapping algorithm based on the implicit function theorem. In addition, the proposed method was applied to the Gurson-Tvergaard-Needleman (GTN) model that considers the influence of damage due to nucleation and growth of microscopic void in materials in the simulation of the nonlinear behaviors. By using the GTN model with the proposed method, an elastic-plastic analysis was performed by the implicit method for a 4-point bending test of pipe with a through-wall crack. The numerical solution of the variation of the load-load line displacement from the analysis agreed with experimental result. Thus, we concluded that the proposed method is useful for simulating nonlinear behaviors, including void nucleation and growth in materials.
Sako, Hiroyuki; Sugimura, Hitoshi; Ahn, J. K.*; Han, Y.*; Hasegawa, Shoichi; Hwang, S. H.*; Ichikawa, Yudai; Imai, Kenichi; Kiuchi, Ryuta*; Ozawa, Kyoichiro; et al.
Nuclear Instruments and Methods in Physics Research A, 763, p.65 - 81, 2014/11
Times Cited Count:5 Percentile:38.2(Instruments & Instrumentation)We developed a prototype TPC for an H-dibaryon search experiment at J-PARC. To investigate its performance, we conducted tests with Ar-CH (90:10) and Ar-CF (95:5), where the former is mainly used. The detection efficiency was measured to be 98% at the beam rate up to cps/cm, and 90% at the rate of cps/cm. Based on the measured horizontal resolution of 0.19-0.46 mm at the drift length of 5-20 cm, the position resolution of better than 0.3 mm is estimated in 1 T magnetic field. The ion backflow fraction was measured to be 5% and reduced up to 3% at the gain of . The horizontal position distortion due to ion backflow in the gate operation was suppressed within mm at the beam rates up to cps/cm. On the other hand, the distortion with the gate open was measured to be mm. The distortion in the final experiment is estimated to be mm.
Sako, Hiroyuki; Ahn, J. K.*; Baek, K. H.*; Bassalleck, B.*; Fujioka, H.*; Guo, L.*; Hasegawa, Shoichi; Hicks, K.*; Honda, R.*; Hwang, S. H.*; et al.
Journal of Instrumentation (Internet), 9(4), p.C04009_1 - C04009_10, 2014/04
Times Cited Count:3 Percentile:16.14(Instruments & Instrumentation)A TPC has been developed for J-PARC E42 experiment to search for H-dibaryon in (, ) reaction. An event with 2 and 2 protons decaying from H-dibaryon is searched for inside the TPC. The TPC has octagonal prism shape drift volume with about 50 cm diameter with 55 cm drift length filled with Ar-CH (90:10) gas. At the end of the drift volume, 3-layer GEMs are equipped. In order to analyze momenta of produced particles, the TPC is applied with 1 T dipole magnetic field parallel to the drift electric field with a superconducting Helmholz magnet. In order to maximize the acceptance of H-dibaryon events, a diamond target is installed inside the TPC drift volume, in a cylindrical hole opened from the top to the middle of the drift volume. Since extremely high-rate beam is directly injected into the TPC drift volume to the target, a gating grid and GEMs are adopted to suppress positive-ion feedback.
Sugimura, Hitoshi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Kiuchi, Ryuta; Ichikawa, Yudai; Hwang, S. H.*; Hasegawa, Shoichi; Tanida, Kiyoshi; J-PARC E10 Collaboration*
Physics Letters B, 729, p.39 - 44, 2014/02
Times Cited Count:31 Percentile:86.9(Astronomy & Astrophysics)We have carried out an experiment to search for a neutron-rich hypernucleus, H, by the Li(,K) reaction at p = 1.2 GeV/c. The obtained missing-mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the H hypernucleus neither below nor above the H+2n particle decay threshold. An upper limit of the production cross section for the bound H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.
Imai, Kenichi; Ichikawa, Yudai; Hasegawa, Shoichi; Sako, Hiroyuki; Sato, Susumu; Kiuchi, Ryuta*; Hosomi, Kenji; Sugimura, Hitoshi; 36 of others*
Few-Body Systems, 54(7-10), p.1191 - 1194, 2013/08
Times Cited Count:11 Percentile:58.46(Physics, Multidisciplinary)In the J-PARC E27 experiment, we search for a bound state via the reaction at 1.7 GeV/c at the K1.8 beam line. The binding energy and decay width of the bound state can be obtained in the missing mass measurement with a good energy resolution of 2 MeV/c. A range counter array (RCA) was constructed to detect the two high-momentum protons from the decay and to reduce the background such as quasi-free hyperon production. Recently, we have carried out a pilot run in June, 2012. The missing-mass spectrum has been obtained for the first time.
Sugimura, Hitoshi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Adachi, Satoshi*; Tanida, Kiyoshi*; Kiuchi, Ryuta*; Joo, C. W.*
AIP Conference Proceedings 1388, p.602 - 604, 2011/10
Times Cited Count:0 Percentile:0.05no abstracts in English
Meguro, Yoshihiro; Tomioka, Osamu; Imai, Tomoki*; Fujimoto, Shigeyuki*; Nakashima, Mikio; Yoshida, Zenko; Honda, Tadashi*; Koya, Fumio*; Kitamura, Nobu*; Wada, Ryutaro*; et al.
Proceedings of International Waste Management Symposium 2004 (WM '04) (CD-ROM), 8 Pages, 2004/03
Supercritical CO fluid leaching (SFL) method using supercritical CO fluid containing a complex of HNO - tri-n-butyl phosphate (TBP) was applied to removal of uranium from radioactive solid wastes. Sea sands, incineration ashes and porous alumina bricks were employed as matrixes of simulated solid wastes. Real radioactive incineration ash wastes and firebrick wastes were also subjected to the SFL treatment. It was found that uranium could be efficiently removed from both of the simulated wastes and real wastes by the SFL method. The removal efficiency of uranium from the real waste was lower than that from the corresponding artificial waste. About 1 g and 35 mg of uranium were recovered from 10 g of the real ash waste and 37 g of the real firebrick waste, respectively.
Goto, Norikazu*; Imai, Ryuta*; Arakawa, Chuichi
Keisan Kogaku Koenkai Rombunshu, 7(1), p.47 - 48, 2002/05
no abstracts in English
Yamada, Susumu; Shimizu, Futoshi; Imai, Ryuta*; Kimizuka, Hajime*; Kaji, Yoshiyuki; Kaburaki, Hideo
Keisan Kogaku Koenkai Rombunshu, 6(1), p.233 - 236, 2001/05
no abstracts in English
Imai, Ryuta*; Arakawa, Chuichi*; Kobayashi, Kenichi*; Hino, Ryutaro; Ishikura, Shuichi*; Kogawa, Hiroyuki; Terada, Atsuhiko*; Haga, Katsuhiro; Watanabe, Tadashi
Dai-14-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu, p.C10_1_1 - C10_1_14, 2000/00
no abstracts in English
Kobayashi, Kenichi*; Arakawa, Chuichi*; Imai, Ryuta*; Hino, Ryutaro; Ishikura, Shuichi*; Kogawa, Hiroyuki; Terada, Atsuhiko*; Haga, Katsuhiro; Watanabe, Tadashi
Dai-14-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu, p.C10_2_1 - C10_2_3, 2000/00
no abstracts in English
Sato, Susumu; Sako, Hiroyuki; Imai, Kenichi; Sugimura, Hitoshi; Adachi, Satoshi; Kiuchi, Ryuta*; Tanida, Kiyoshi*; Miwa, Koji*; Ozawa, Kyoichiro*
no journal, ,
no abstracts in English
Sako, Hiroyuki; Imai, Kenichi; Sato, Susumu; Sugimura, Hitoshi; Ichikawa, Yudai; Hasegawa, Shoichi; Shirotori, Kotaro; Kiuchi, Ryuta*; Honda, Ryotaro
no journal, ,
Recent Lattice-QCD calculations show the baryon-baryon potential corresponding to the H-dibaryon is attactive, and predicts H-dibaryon is either a weakly bound state or a resonance state. On the other hand, KEK-E224, E522 experiments observed a peak near the invariant mass spectrum, which suggests existence of H-dibaryon. However, due to low statistics and low mass resolution, they did not discover the evidence for H-dibaryon. We propose an experiment (P-42) to search for H-dibaryon at J-PARC with Kaon beams with improved statistics and mass resolutions. In this experiment, a dipole magnet spectrometer based on high-rate capable GEM-TPC is designed to reconstruct 2 protons and to 2 s decaying from a H-dibaryon.
Imai, Kenichi; Kiuchi, Ryuta*
no journal, ,
We have developed Silicon Strip Detector (SSD) for measurements of particle tracks at J-PARC hadron facility. We reported performance of a prototype SSD in the past JPS meeting (2010 Spring), and recently we success the data suppression method by FPGA to reduce the data readout time and we have confirmed it works well during a test experiment at RCNP in 2011. In this presentation, we will report the performance of our SSD and the results of data suppression by FPGA.
Sato, Susumu; Sako, Hiroyuki; Hasegawa, Shoichi; Sugimura, Hitoshi; Ichikawa, Yudai; Ozawa, Kyoichiro; Kiuchi, Ryuta*; Hwang, S. H.*; Imai, Kenichi
no journal, ,
no abstracts in English
Sako, Hiroyuki; Imai, Kenichi; Sato, Susumu; Hasegawa, Shoichi; Hwang, S. H.*; Sugimura, Hitoshi; Ichikawa, Yudai; Tanida, Kiyoshi; Kiuchi, Ryuta*; Ahn, J. K.*; et al.
no journal, ,
The H-dibaryon has been proposed as a stable 6-quark sate, and various experiments have been performed to search for it, but never been successful. KEK-PS E224 and E522 experiments observed peaks near the threshold in the invariant mass spectra although statistics is not enough. On the other hand, recent lattice QCD calculations predict the H is a shallow bound state or a resonance state. We proposed J-PARC E42 experiment to search for the H-dibaryon in (,) reaction with two-order higher statistics and higher mass resolutions.
Sako, Hiroyuki; Imai, Kenichi; Sato, Susumu; Hasegawa, Shoichi; Hwang, S. H.*; Sugimura, Hitoshi; Ichikawa, Yudai; Tanida, Kiyoshi; Kiuchi, Ryuta*
no journal, ,
J-PARC E42 is an experiment to search for the H-dibaryon in (,) reactions. The experimental setup consists of a larget solid angle TPC, a Helmholtz dipole magnet, and a spectrometer (Kurama). We have performed an experiment of a prototype TPC injecting a UV laser under magnetic field with the FM magnet in the J-PARC hadron facility hall. We have been also developing the second TPC which has the real size the pad plane and GEMs. In this presentation, we report the results of the prototype TPC and the status for the second TPC.
Mano, Akihiro; Imai, Ryuta*; Katsuyama, Jinya; Li, Y.
no journal, ,
Ductile fracture due to large loading is one of the most severe fracture modes for important nuclear components. The finite element method based on damage mechanics is known as useful for simulating ductile fracture including ductile crack growth. In International Cooperative Research Program on Ductile Fracture Simulation, to confirm the appropriateness of damage mechanics analysis models to ductile fracture of cracked pipes, benchmark analyses have been performed by using various analysis codes and models. In this study, as a part of the benchmark analyses, the appropriateness of two damage mechanics analysis models, stress modified fracture strain model and Gurson-Tvergaard-Needleman model, are investigated through the analyses for 4 point pipe bending tests under monotonic and cyclic loading conditions. Also, a concept to consider the effect of ductility on fracture behaviors of components subjected to cyclic straining is applied to the analyses. Based on the analysis results, it is confirmed that above damage mechanics analysis models can simulate the test results such as crack growth extension vs. load-line displacement.
Mano, Akihiro; Imai, Ryuta*; Miyamoto, Yuhei*; Katsuyama, Jinya; Li, Y.
no journal, ,
Finite element analysis (FEA) based on Gurson-Tvergaard-Needleman (GTN) model is utilized for the simulation of the non-linear plastic behavior of a material. In the analysis, the variation of the size of yield surface based on the void nucleation, growth and coalescence in a material is considered. When the analysis is conducted by an implicit method, the stress values are generally updated with a time increment considering the size of yield surface by using the so-called return mapping algorithm. This algorithm requires solving simultaneous nonlinear equations related to a constitutive model. Thus, their solutions are usually obtained by an iterative calculation scheme. However, when the number of equations is large as with the GTN model, it becomes difficult to obtain the converged solutions in the iterative calculation scheme. In the commercial FEA software Abaqus version 2018, the analysis based on the GTN model considering the void coalescence cannot be performed by the implicit method, in which the converged solutions are difficult to obtain. In this research, the number of equations in return mapping algorithm of the GTN model was reduced by applying the implicit function theorem and the convergence of the analysis was improved. Based on the return mapping algorithm improved regarding the number of equations, the analysis based on GTN model was conducted by the implicit method in Abaqus taking the 4-point pipe bending test as an example. As the result, it was confirmed that the variation in load against displacement in the test could be simulated.