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)

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.

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.

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.

Speed Sensorless Control of Ultrasonic Motors Using Neural Network

Yoshida Tomohiro,Senjyu Tomonobu,Nakamura Mitsuru,Urasaki Naomitsu,Funabashi Toshihisa,Sekine Hideomi The Korean Institute of Power Electronics 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.1

In this paper, a speed sensorless control for an ultrasonic motor (USM) using a neural network (NN) is presented. In the proposed method, rotor speed is estimated by a three-layer NN which adapts nonlinearities associated with load torque and motor temperature into control. The intrinsic properties of a USM, such as high torque for low speeds, high static torque, compact size, etc., offer great advantages for industrial applications. However, the speed property of a USM has strong nonlinear properties associated with motor temperature and load torque, which make accurate speed control difficult. These properties are considered in designing a control method through the application of mathematical models. In these strategies, a detailed speed model of the USM is required which makes actual applications impractical. In the proposed method, a three-layer NN estimates the speed of the USM from the drive frequency, the root mean square value of input voltage and the surface temperature of the USM, where no mechanical speed sensor is needed. The NN speed based estimator enables inclusion of variations in driving conditions due to input signals of the NN involved during the driving state of the USM. The disuse of sensors offers many advantages on both the cost and maintenance front. Moreover, the model free sensorless control method offers practical controller construction within a small number of parameters. To validate the proposed speed sensorless control method for a USM, experiments have been executed under several conditions.

Comparison of Preschooler's Exercise Intensity at Kindergarten and at Home

YOSHIDA Izumi 아시아아동지원학회 2015 아시아아동지원연구 Vol.6 No.-

검정교과서체제기 수신서에 투영된 여성상-메이지 시대 이노우에 료엔편 중등여자수신훈 -

YOSHIDA YUKO 한국일본어교육학회 2023 日本語敎育 Vol.- No.104

In this paper, we analyzed the Inoue Enryo edition “Moral Training Book for Secondary Education Women” published in 1905, which can be said to be the great turning point of elementary education from an authorized textbook to a national textbook to examine what the image of women projected in the moral training book of the secondary educatin curriculum was from two perspectives “women’s duty” and “enterprising new thought.” The aggregation of this “women’s duty” can be said to be the “good wife and wise mother.” There has until now been the custom that women in secondary or higher societies should not have a job, however, the “enterprising new thought” encourages to eliminate it. In this way, it could be understood that the women’s view of Western countries was increasingly infiltrating the moral training book as well. But it still had a lot of limitations. As the final conclusin of what was the female image projected in this moral training book, ‘kusunoki Masatsura’s mother’ can be cited. In the Middle Ages of Japan, which walked the two paths of loyalty and filial piety, it can refer to the figure who completed the “good wife and wise mother. ” This ‘wise mother and wife’ has been elevated and educated as women’s international responsibility in the section of ‘international Obligatins’ in the moral trainig book. To change the poinnt of view, it can be said that the ideology of nationatizumu has created a motern wise mother and wife. 본고에서는 초등교육이 검정교과서에서 국정교과서로 이행한 대전환기라고 할 수 있는 1905년에 출판된 이노우에 엔료편 중등 여자 수신훈 을 분석해, 중등 교육 과정의 수신서에 투영된 여성 상은 무엇이었는지를 ‘여덕’과 ‘진취적 신사상’이라는 두 가지 관점에서 고찰했다. 이 ‘여덕’의 집대성이 ‘현모양처’라고 할 수 있다. ‘진취적 신사상’은 지금까지는 중등 이상의 사회의 부녀는 직업 등 해야 할 것이 아닌 관습이 있었지만 폐절을 장려하고 있다. 이처럼 서양 국가의 여성관이 점점 수신서에도 침투하고 있다는 것을 이해할 수 있었다. 그러나 그것은 아직도 많은 제한이 있었다. 이 수신서에 투영된 여성상은 무엇이었는지 최종적인 결론으로 ‘쿠스노키 마사쓰라의 어머니’를 들 수 있다. 충효의 두 길을 걸고 일본의 중세시대에 있어서는, ‘현모’를 완수한 인물이라고 할 수 있을 것이다. ‘현모양처’는 수신서의 ‘국제에 관한 의무’라는 항목 속에 여성의 국제적인 책무로 격상되고 교육되어왔다. 견해를 바꾸면, 국가주의 이데올로기가 근대적인 현모양처를 만들었다고 할 수 있다.

CURRENT STATUS OF THE INSTRUMENTS, INSTRUMENTATION AND OPEN USE OF OKAYAMA ASTROPHYSICAL OBSERVATORY

YOSHIDA MICHITOSHI The Korean Astronomical Society 2005 Journal of The Korean Astronomical Society Vol.38 No.2

Current instrumentation activities and the open user status of Okayama Astrophysical Observatory (OAO) are reviewed. There are two telescopes in operation and one telescope under reforming at OAO. The 188cm telescope is provided for open use for more than 200 nights in a year. The typical over-subscription rate of observation proposals for the 188cm telescope is ${\~}$ 1.5 - 2. The 50cm telescope is dedicated to $\gamma$-ray burst optical follow-up observation and is operated in collaboration with Tokyo Institute of Technology. The 91cm telescope will become a new very wide field near-infrared camera in two years. The high-dispersion echelle spectrograph (HIDES) is the current primary instrument for the open use of the 188cm telescope. Two new instruments, an infrared multi-purpose camera (ISLE) and an optical low-dispersion spectrograph (KOOLS), are now under development. They will be open as common use instruments in 2006.