• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.385-388
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• 2000

During the deep drawing process an initially flat blank is clamped between the die and the blank holder after which the punch moves down to deform the clamped blank into the desired shape. In general, sheet metal forming may involve stretching, drawing, bending or various combinations of those basic modes of deformation. The deformation problems of sheet metal working involve non-linearity in geometry and material. In this work, The punch load and thickness strain of electro-galvanized sheet steel (SECD) for elliptical deep drawing are examined under the various process conditions including, punch shape radius, die shape radius. The changes of punch load and thickness strain distribution of the deformed elliptical cup are affected by the size of each die shape radius.

• 한국정밀공학회지
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• 제18권8호
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• pp.182-192
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• 2001

During the deep drawing process an initially flat blank is clamped between the die and the blank holder after which the punch moves down to deform the clamped blank into the desired shape. In general, sheet metal forming may involve stretching, drawing, bending or various combinations of those basic modes of deformation. The deformation problems of sheet metal working involve non-linearity in geometry and material. In this work, The punch load and thickness strain of electro-galvanized sheet steel (SECD) for elliptical deep drawing are examined under the various process conditions including, punch shape radius, die shape radius. The changes of punch load and thickness strain distribution of the deformed elliptical cup are affected by the size of each die shape radius.

• 소성∙가공
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• 제10권3호
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• pp.235-245
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• 2001

Deep drawing process, one of sheet metal forming methods, is very useful in the industrial field because of its efficiency The deep drawing is affected by many process variables, such as blank shapes, shape radii of the punch and die, formability of materials and so on. Especially, blank shape is very important formability factor. In this study, in order to investigate the effects of blank shape, we suggested three kinds of blank shapes and examined friction test about three conditions. We measured punch load distribution according to punch stroke under the conditions of each punch and die shape radii and observed punch load of elliptical cup forming.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.1021-1025
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• 2002

There have been many researches performed on the formability of axisymmetric or rectangular cup shapes in the deep drawing processes. But non-axisymmetric deep drawing processes rely upon empirical knowledge of experts in most cases. Especially, there have been few researches for multi-stage elliptical deep drawing processes. In this study, formability and thickness distributions of elliptical yoke products were predicted by using finite element analysis. The results of the analysis were compared with those of experiments for validity.

• 소성∙가공
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• 제11권8호
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• pp.668-675
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• 2002

The circles deform into various shape during deformation, the major and minor axes of which indicate the direction of the major and minor principal strains. Likewise, the measured dimensions are used to determine the major and minor principal strain magnitudes. This circular grid technique of measuring strains can be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, of incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.124-127
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• 2000

The finite element analyses of the wrinkling initiation and growth in the sheet metal forming process provide the detailed information about the wrinkling behavior of sheet metal. The direct analyses of the wrinkling initiation and growth, however, bring about a little difficulty in complex industrial problems because it needs large memory size and long computation time. For the description of wrinkling growth, the mesh elements should be sufficiently small and the size of finite element matrix becomes large. In the static implicit finite element method therefore, the direct analysis of wrinkling growth in a complex sheet metal forming process is rather difficult. From the industrial viewpoint of tooling design, the readily available information of possibility and location of wrinkling is sometimes more preferable to the detailed time-consuming information. In the present study, therefore, the wrinkling factor that shows locations and relative possibility of wrinkling initiation is proposed as a convenient tool of relative wrinkling estimation based on the energy criterion. The location and relative possibility of wrinkling initiation are predicted by calculating the wrinkling factor in various sheet metal forming processes such as cylindrical cup deep drawing, spherical cup deep drawing, and elliptical cup deep drawing. The wrinkling factor is also implemented in the analysis of the door inner stamping process to predict wrinkling.

• Parasites, Hosts and Diseases
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• 제57권5호
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• pp.521-524
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• 2019

We are going to describe the female soboliphymid nematodes, which were recovered from the stomach of a Asian badger, Meles leucurus (Mammalia: Mustelidae), in Geochang-gun, Gyeongsangnam-do, Korea. In February 1998, we found 2 peculiar nematodes with a cup-like organ in the anterior end from the stomach of badger. Recovered worms were fixed with 10% formalin, cleared in glycerin-alcohol solution and observed under a light microscope with a micrometer. They were 34.46 (33.43-35.50) mm long by 2.13 mm at maximum width. Cephalic sucker cup-like, 3.34 (3.13-3.55) mm wide, 2.40 (2.25-2.55) mm long, with the oral aperture and meridionally striated on the buccal capsule. Oral aperture 2.38 mm in diameter. Circumoral membrane 0.41 (0.38-0.45) mm wide. Esophagus muscular, 4.81 (4.50-5.00) mm long by 0.80 (0.78-0.83) mm at maximum width. Vulva situated at 3.13 mm ventro-anterior level from the esophago-intestinal junction. Vagina anteriad, 3.38 mm long, making a canal from the uterus to the vulva opening. Uterus single, large. Tail 0.35 (0.33-0.38) mm long. Intrauterine eggs long elliptical, 0.058-0.065 (0.062) mm long and 0.030-0.033 (0.031) mm wide. Based on the some morphological characters and host-specificity, our specimens are nearly identical with S. baturini. Therefore, the present report describes S. baturini for the first time in Korea.

• 소성∙가공
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• 제11권8호
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• pp.682-690
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• 2002

The formation of adiabatic shearband in tungsten heavy alloys(WHA) was studied in this investigation. Five prismatic specimens were loaded by high velocity impacts and treated as plane strain problems. To find out the effect of particle's volume ratio, specimens containing 81%, 93% and 97% volume percents of tungsten particles were used. Also the effects of particle's geometry and size on the formation of shearband were studied for 81% volume percent alloys by small size particle model, large size particle model and undulated particle models, and the results were discussed.be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, or incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.