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Journal Articles

Improvement of the return mapping algorithm based on the implicit function theorem with application to ductile fracture analysis using the GTN model

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.

Journal Articles

Development of a prototype GEM TPC with a gating grid for an H-dibaryon search experiment at J-PARC

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$$_{4}$$ (90:10) and Ar-CF$$_{4}$$ (95:5), where the former is mainly used. The detection efficiency was measured to be 98% at the beam rate up to $$5times10^{5}$$ cps/cm$$^{2}$$, and 90% at the rate of $$3times10^{6}$$ cps/cm$$^{2}$$. 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 $$1.6times10^{4}$$. The horizontal position distortion due to ion backflow in the gate operation was suppressed within $$pm 0.2$$ mm at the beam rates up to $$5times10^{5}$$ cps/cm$$^{2}$$. On the other hand, the distortion with the gate open was measured to be $$pm2$$ mm. The distortion in the final experiment is estimated to be $$0.3 pm 0.2$$ mm.

Journal Articles

Development of a GEM-TPC for H-dibaryon search experiment at J-PARC

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 ($$K^-$$, $$K^+$$) reaction. An event with 2 $$pi^-$$ 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$$_{4}$$ (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 $$K^-$$ beam is directly injected into the TPC drift volume to the target, a gating grid and GEMs are adopted to suppress positive-ion feedback.

Journal Articles

Search for $$^6_{Lambda}$$H hypernucleus by the $$^{6}$$Li($$pi^-,K^+$$) reaction at $$p_pi$$- = 1.2 GeV/$$c$$

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, $$^6_Lambda$$H, by the $$^{6}$$Li($$pi$$$$^{-}$$,K$$^{+}$$) reaction at p$$_{pi-}$$ = 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 $$^6_Lambda$$H hypernucleus neither below nor above the $$^4_Lambda$$H+2n particle decay threshold. An upper limit of the production cross section for the bound $$^6_Lambda$$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

Journal Articles

J-PARC E27 experiment to search for a nuclear Kaon bound state $$K^-pp$$

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 $$K^-pp$$ bound state via the $$d(pi^{+}, K^+)$$ reaction at 1.7 GeV/c at the K1.8 beam line. The binding energy and decay width of the $$K^-pp$$ bound state can be obtained in the missing mass measurement with a good energy resolution of 2 MeV/c$$^2$$. A range counter array (RCA) was constructed to detect the two high-momentum protons from the $$K^-pp$$ decay and to reduce the background such as quasi-free hyperon production. Recently, we have carried out a pilot run in June, 2012. The $$d(pi^{+}, K^+)$$ missing-mass spectrum has been obtained for the first time.

Journal Articles

Development of silicon strip detector for the measurement of the $$Xi$$-atom X-rays

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:0.05

no abstracts in English

Journal Articles

Removal and recovery of uranium from solid wastes by supercritical carbon dioxide fluid leaching method

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$$_{2}$$ fluid leaching (SFL) method using supercritical CO$$_{2}$$ fluid containing a complex of HNO$$_{3}$$ - 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.

Journal Articles

An Analysis of the accident in Super-Kamiokande

Goto, Norikazu*; Imai, Ryuta*; Arakawa, Chuichi

Keisan Kogaku Koenkai Rombunshu, 7(1), p.47 - 48, 2002/05

no abstracts in English

Journal Articles

PARCEL; Performance evaluation by structural analysis calculation

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

Journal Articles

Development of fluid-structure interaction code for mercury target, 1

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

Journal Articles

Development of fluid-structure interaction for mercury target, 2

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

Oral presentation

Development of taraget-containing-type of TPC-4$$pi$$-spectrometer

Sato, Susumu; Sako, Hiroyuki; Imai, Kenichi; Sugimura, Hitoshi; Adachi, Satoshi; Kiuchi, Ryuta*; Tanida, Kiyoshi*; Miwa, Koji*; Ozawa, Kyoichiro*

no journal, , 

no abstracts in English

Oral presentation

Design of spectrometer for H-dibaryon search at J-PARC

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 $$LambdaLambda$$ 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 $$10^{6}$$ 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 $$pi^{-}$$s decaying from a H-dibaryon.

Oral presentation

Performance of the silicon detector

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.

Oral presentation

Developments of gate functioning used GEM

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

Oral presentation

Search for H-dibaryon in ($$K^{-}$$,$$K^{+}$$) reaction at J-PARC, 1

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 $$Lambda$$ $$Lambda$$ 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 ($$K^{+}$$,$$K^{-}$$) reaction with two-order higher statistics and higher mass resolutions.

Oral presentation

Development of TPC for J-PARC-E42 experiment; Performance evaluation of a prototype TPC in the magnetic field and development of large area GEMs

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 ($$K^{-}$$,$$K^{+}$$) reactions. The experimental setup consists of a larget solid angle TPC, a Helmholtz dipole magnet, and a $$K^{+}$$ 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.

Oral presentation

Benchmark analysis for ductile fracture simulation; Analysis by Japan Atomic Energy Agency

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.

Oral presentation

Improvement of return mapping algorithm in GTN model by reducing the number of equations to be solved

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.

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