• Korean Journal of Metals and Materials
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• v.50 no.1
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• pp.8-12
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• 2012

This study aims to analyze the formability property of surface texturing processed automotive steel sheet for improving the sheet forming property. In the paper, the effect of cavities fabricated using the laser surface texturing technique on automotive high strength steel sheets was studied. The frictional behavior of the sheet drawing is a function of interface parameters such as sheet surface roughness, holding force, contact pressure, etc. For these reasons, automotive steel researchers want to optimize the surface topography of automotive steel sheets in order to enhance the formability. Therefore, this study presents the behavior of deformation of a laser surface texturing steel sheet by considering the frictional operation during the deep drawing process.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.982-999
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• 2006

In this paper, we propose an automatic facial phrenology analysis and avatar drawing system based on internet using multi color information and face geometry. In the proposed system, we detect face using logical product of Cr and I which is a components of YCbCr and YIQ color model, respectively. And then, we extract facial feature using face geometry and analyze user's facial phrenology with the classification of each facial feature. And also, the proposed system can make avatar drawing automatically using extracted and classified facial features. Experimental result shows that proposed algorithm can analyze facial phrenology as well as detect and recognize user's face at real-time.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.92-95
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• 2011

In manufacturing optical fibers, the process starts with the glass fiber drawing from the heated and softened silica preform in the furnace, and the freshly drawn glass fiber is still at high temperature when it leaves the glass fiber drawing furnace. It is necessary to cool down the glass fiber to the ambient temperature before it then enters the fiber coating applicator, since the hot glass fiber is known to cause several technical difficulties in achieving high quality fiber coating. As the fiber drawing speed keeps increasing, a current manufacturing of optical fibers requires a dedicated cooling unit with helium gas injection. A series of three-dimensional flow and heat transfer computations are carried out to investigate the effectiveness of fiber cooling in the fiber cooling unit. The glass fiber cooling unit is simplified into the long cylindrical enclosure at which the hot glass fiber passes through at high speed, and the helium is being supplied through several injection slots of rectangular shape along the cooling unit. This study presents and discusses the effects of helium injection rates on the glass fiber cooling rates.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.660-669
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• 1989

The strain distribution in a wide strip drawn through a wedge-shaped die is obtained from the numerical integration of strain increments along the flow path of material points in the slipline field for a non-hardening material under the plane strain condition. It is shown that the strain in the surface layer increases with friction and that the strain at the mid-plane is a function of area reduction only. The redundant deformation factor, obtained from the average strain in a drawn strip, increases with friction. For the workability analysis of a strip drawing process, the strain states along with hydrostatic stresses are needed for the evaluation of a damage function based on the hole-growth mechanism of ductile fracture. The critical maximum of the damage function is assumed to be a material constant. As a result, mid-plane cracking is likely to occur in a process at a small reduction, with a large die angle, and in poor lubrication. Distortions of an initially transverse line are also calculated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.374-377
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• 2008

Magnesium alloy sheets are usually formed at temperatures between $150^{\circ}C$and $300^{\circ}C$ because of their poor formability at room temperature. In the present study, the formability of AZ31B magnesium alloy sheets was investigated by the analytical and experimental approaches. First, tensile tests and the limit dome height test were carried out at elevated temperatures to get the mechanical properties and forming limit diagram, respectively. And then deep drawing of cross shaped die was tried to get the minimum corner radius and forming limit at specific temperature. Blank shape, punch velocity, minimum corner radius, fillet size, etc, were determined by finite element analysis physical try-outs. Especially, optimum punch and die temperature were suggested through the temperature-deformation analysis using Pam-stamp.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.961-968
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• 2022

Hydrogen embrittlement leads to the damages in bolts, nut, especially, high pressure valves, in the semiconductor facilities, hydrogen vehicles, hydrogen stations and so on. Monel material has higher strength than SUS material. Therefore, even though Monel material with special alloy is usually used to prevent the hydrogen embrittlement, it needs powerful drawing system to manufacture the rectangular or hexagonal bar using circular bar. The purpose of this study is to investigate the characteristics of plastic deformation of Monel material and 2 rollers of rolling unit in plastic limit through numerical analysis. As the results, it was predicted that, based on mean stress, as the rolling step was increased, the rolling force of rolling unit was decreased. In addition, the heat treatment for Monel material was needed because of residual stress due to plastic deformation. As for rollers, the roller was safe about 1.86 times compared with that of ultimate strength. In this study, as the roller 2 showed larger stress than roller 1, thus, roller 2 should be designed carefully to guarantee the safety. Further it was confirmed that the reaction force of roller could be helpful in bearing design.

• Transactions of Materials Processing
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• v.32 no.5
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• pp.268-275
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• 2023

ISO 21029 cryogenic vessel is used to transport cryogenic fluids. High-manganese steel (High-Mn steel) is widely regarded as suitable for use at cryogenic temperatures. The conventional way of manufacturing an ellipsoidal vessel head involves incremental stretching, followed by a spinning process. In this study, an alternative method for forming an ellipsoidal vessel head was proposed. Finite element analysis (FEA) was used to theoretically examine the strain evolution during a multi-stage forming process, which involved progressive stretching, deep drawing, and spinning of High-Mn steel. The distribution of effective strain and strain components were analyzed at different regions of the formed part. The FEA results revealed that only normal strains were evident in the dished region of the vessel head due to the stretching process. However, the flange region experienced complex strain evolution during the subsequent deep drawing and spinning process.

• Cartoon and Animation Studies
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• s.35
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• pp.1-27
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• 2014

This study is a process of studying an alternative educational model and a preceding analysis process of the study where a teaching method considering the brain function, learning and creative mechanism is applied with a perspective of effectively increasing the animation drawing ability. Recently, studies in each field of study is not simply limited to one major but are attempting to produce subdivided integrated educational contents through integrated study activities with other fields. It is because for any field, it has a complex structure of humanistic experience and this is the same for artistic fields. Especially, in the field of animation, a specialized area is subdivided so when looking only at the education related to the drawing, the items required for expertise should be clarified and the development of a systematic educational method is required. Therefore in this study, a literature study result to design the educational model suitable for professional characteristics of animation education method is proposed. The study aims to conceptualize and categorize the meaning of drawing that can refine the basic ability for education of animation field to suit the characteristics of majoring field. Afterwards, the components are derived through re-established concept of drawing and categories, and this becomes the basis for the process of materializing the study goal which is the follow-up work. As a result, the components are examined by defining the meaning of drawing as the motion drawing due to the characteristics of the picture contents field, and used as a basis for planning the educational model applied with brain scientific creative-learning principles.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.11a
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• pp.175-180
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• 2003

• Transactions of Materials Processing
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• v.26 no.2
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• pp.79-86
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• 2017

In this study, the sheet metal forming process of the brake chamber head, which had a complex shape compared to the conventional head part, was investigated using finite element (FE) analysis. In order to prevent the forming failures such as necking and fracture, the multi-stage forming process was introduced. The forming process consisted of three steps: (1) first drawing, (2) second drawing, (3) final forming. Experimental and FE simulated results of the brake chamber head were compared, and the results showed that the required characteristics of the straightness and the wall thickness at each location were satisfied.