Material Models for Accurate Simulation of Sheet Metal Forming and Springback

Fusahito YOSHIDA 한국소성가공학회 2010 기타자료 Vol.2010 No.6

For anisotropic sheet metals, modeling of anisotropy and the Bauschinger effect is discussed in the framework of Yoshida-Uemori kinematic hardening model incorporating with anisotropic yield functions. The performances of the models in predicting yield loci, cyclic stress-strain responses on several types of steel and aluminum sheets are demonstrated by comparing the numerical simulation results with the corresponding experimental observations. From some examples of FE simulation of sheet metal forming and springback, it is concluded that modeling of both the anisotropy and the Bauschinger effect is essential for the accurate numerical simulation.

Reduction of Springback of Sheet Metals by Bottoming

Takayuki Ogawa,Atsushi Hirahara,Fusahito Yoshida 한국소성가공학회 2010 기타자료 Vol.2010 No.6

The effect of bottoming on the reduction of springback is investigated by performing V-air-bending experiment on a high strength steel sheet of TS590MPa and the corresponding FE simulation. From the experiment, it was found that the springback is drastically decreased with increasing bottoming force. This is mainly due to the reduction of bending moment by compressive load acting normally to the sheet. At an early stage of bottoming, springback is also influenced by the change of geometrical rigidity of the bent sheet due to the straightening of ridge line warp. Since bottoming is a process of reverse deformation of tension-compression, the Bauschinger effect of materials should be taken into account for its accurate numerical simulation. 3D FE simulation using Yoshida-Uemori kinematic hardening model predicts well the bottoming effect.

Elasto-Plasticity Behavior of Type 5000 and 6000 Aluminum Alloy Sheets and Its Constitutive Modeling

Shohei TAMURA,Satoshi SUMIKAWA,Hiroshi HAMASAKI,Takeshi UEMORI,Fusahito YOSHIDA 한국소성가공학회 2010 기타자료 Vol.2010 No.6

To examine the deformation characteristic of type 5000 and 6000 aluminum alloy sheets, uniaxial tension, biaxial stretching and in-plane cyclic tension-compression experiments were performed, and from these, r-values (r?, r45 and r90), yield loci and cyclic stress-strain responses were obtained. For the accurate description of anisotropies of the materials, high-ordered anisotropic yield functions, such as Gotoh’s biquadratic yield function and Barlat’s Yld2000-2d, are necessary. Furthermore, for the simulation of cyclic behavior, an advanced kinematic hardening model, such as Yoshida-Uemori model (Y-U model), should be employed. The effect of the selection of material models on the accuracy of the springback prediction was discussed by performing hat bending FE simulation using several yield functions and two types of hardening laws (the isotropic hardening model and Y-U model)

Interrogative Feature Checking in Japanese and Korean

( Keiko Yoshida ),( Tomoyuki Yoshida ) 한국언어정보학회 1996 국제 워크샵 Vol.1996 No.-

This paper discusses the feature checking mechanism of interrogative sentences in Japanese and Korean. We first focus on a phenomenon of omitting question markers in informal speech in Japanese and attempt to provide an account for it within the framework of Principles and Parameters approach. We argue that question markers can be omitted only if interrogative features of the sentence can be properly checked. In particular we claim that I-to-C head-movement is one of the options for interrogative feature checking in Japanese as well as languages without question markers. A close examination of Korean reveals certain differences between Korean and Japanese. Some theoretical consequences from this analysis are also discussed.

MAGNETIC PROPERTIES OF FePt₃ ORDERED ALLOY

H.Yoshida,H.Fujimorl,T.Kaneko,S.Abe,K.Watanabe,M.Matsumoto,T.Yoshida,T.Kanomata 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5

The magnetic properties for Fe₂₄Pt_(76) and Fe_(26)Pt_(74) have been investigated. The temperature vs. magnetic susceptibility curve for Fe₂₄Pt_(76) had no peak near the Neel temperature. The magnetization process at 4.2 K showed only a linear variation up to the high magnetic field of 240 kOe. That for Fe_(26)Pt_(74) at 77 K showed a metamagnetic transition at 100 kOe. These properties were discussed on the basis of a band picture.

Incremental Parsing in Conditionals and Relative Clauses in Korean

Masaya Yoshida,윤수원,신정아 한국생성문법학회 2022 생성문법연구 Vol.32 No.4

The strong head-finality of Korean raises many potential challenges to incremental parsing. In languages like Korean, there is normally no indication of clause structure before the parser encounters the verb or the relative head at the end of the clause. This uncertainty of clause structure can potentially give rise to processing difficulty of verbs in head-final languages. Developing our earlier studies in Japanese (Yoshida 2006), we present four series of experiments in Korean (offline and online) to show that there are, however, cases where the processing of clause-final verbs can indeed be predicted and facilitated.

Production of Organic Acids and Amino Acids from Fish Meat by Sub-Critical Water Hydrolysis

Yoshida, Hiroyuki,Terashima, Masaaki,Takahashi, Yohei 嶺南大學校 環境問題硏究所 1999 環境硏究 Vol.19 No.1

Fish meat was easily liquefied by hydrolysis under aubcritical conditions without oxidants, and aqueous phase and water-insoluble phase containing oil and fat-like solid were farmed. Lactic acid found in the raw fish meat (about 0.03 g/g-dry meat) was stable up to the reaction temperature 513 K (3.35 MPa). Pyroglutamic acid was produced with a field of 0.095 kg/kg of dry meat by 30 min reaction at 553 K (6.42 MPa). Amino acids such as cystine, alanine, glycine, and leucine were produced in the temperature range 513-623 K with a maximum peak at 543 K. Amounts of crystine, alanine, glycine, and leucine produced in 5 min at 543 K(5.51 MPa) were 0.024, 0.013, 0.009, and 0.004 kg/kg of dry meat, respectively. The oil extracted with hexane contained useful fatty acids such as eicosapentanoic acid (EPA) and docosahexianoic acid (DHA). Thus, subcritical water hydrolysis would be an efficient process for recovering useful substances from organic waste such as fish waste discarded from fish market.

Multiple-Packet Reception MAC Protocol Applying Pulse/Tone Exchange in MIMO Ad-Hoc Networks

Yoshida, Yuto,Komuro, Nobuyoshi,Ma, Jing,Sekiya, Hiroo Korea Multimedia Society 2016 The journal of multimedia information system Vol.3 No.4

This paper proposes a medium access control (MAC) protocol for multiple-input multiple-output (MIMO) ad-hoc networks. Multiple-packet receptions in MIMO systems have attracted as a key technique to achieve a high transmission rate. In the conventional protocols for multiple-packet receptions, timing offsets among multiple-frame transmissions cause frame collisions induced by hidden nodes, which degrades network performance. In the proposed protocol, transmission synchronization among hidden nodes can be achieved by applying pulse/tone exchanges. By applying the pulse/tone exchanges, multiple-packet receptions among hidden nodes can be achieved, which enhances network throughputs compared with the conventional protocol. Simulation results show effectiveness of the proposed protocol.

Cryogenic cooling system for HTS cable

Yoshida, Shigeru The Korea Institute of Applied Superconductivity a 2017 한국초전도저온공학회논문지 Vol.19 No.2

Recently, Research and development activity of HTS (High Temperature Superconducting) power application is very progressive worldwide. Especially, HTS cable system and HTSFCL (HTS Fault current limiter) system are proceeding to practical stages. In such system and equipment, cryogenic cooling system, which makes HTS equipment cooled lower than critical temperature, is one of crucial components. In this article, cryogenic cooling system for HTS application, mainly cable, is reviewed. Cryogenic cooling system can be categorized into conduction cooling system and immersion cooling system. In practical HTS power application area, immersion cooling system with sub-cooled liquid nitrogen is preferred. The immersion cooling system is besides grouped into open cycle system and closed cycle system. Turbo-Brayton refrigerator is a key component for closed cycle system. Those two cooling systems are focused in this article. And, each design and component of the cooling system is explained.

The Global Welfare of Illegal Immigration in the Presence of Capital Mobility

Yoshida, Senri C. 세종대학교 국제경제연구소 1996 Journal of Economic Integration Vol.11 No.4

Using the Bond and Chen [1987] model on illegal immigration, we newly examine the effects of internal enforcement by host country's government on labor-importing country, labor-exporting country and global welfare when capital is allowed to be internationally mobile between a home and a foreign countries. The main results we obtain are that an imposition of the enforcement makes the labor-importing country's welfare better off under some circumstances and the labor-exporting country's welfare better off as well, and hence improves the global welfare. Therefore, we can conclude that the enforcement is a Pareto-improving-policy. (JEL Classification No. : F 21; F22)