• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.78-84
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• 2006

The objective of this study is to design the optimal die profile that can prevent material fracture in the tube drawing process for automobile steering input shaft. First, the CDV(Critical Damage Value) of material is obtained by the compression test and FE-analysis. The occurrence of fracture is estimated by the FE-analysis considering the CDV. In order to achieve the objective of this study, optimization technique and FE-analysis are applied. FPS(Flexible Polyhedron Search) method, which is one of the non-gradient optimization techniques often used in engineering, is used to search optimal die profile. The drawing die profile is represented by Bezier-curve to generate all the possible die profile. Using FPS method and FE-analysis the optimal drawing die profile is determined. To verify tile effectiveness of the redesigned optimal die, the tube drawing experiment is performed. In the experimental result, it is possible to produce sound product without material fracture using the redesigned optimal die.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.6
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• pp.16-28
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• 2001

The purpose of this study is to arrange the terminology of the drawings in Chosun Dynasty, and to investigate the characteristics of drawings after the middle of Chos n Dynasty. This study is based on the and analysis of historic documents and drawings including drawings from China and Japan. In order to accomplish this, the drawings for the process of design were studied first, and the techniques of drawing were studied next in comparison with Japanese drawing techniques. Lastly, the technicians of drawing were studied. The results of this study were as follows; 1) Though the procedures of design Choson dynasty were not divided into planning, designing, construction and maintenance just like those of modern society, a variety of drawings in that time were used in each level. 2) The drawings in Choson Dynasty ere divided into Tohyong and Tosol, and mostly, those for design and construction were Tohy ng. 3) Based on the interpretation of Japanese drawings, several suggestions were presented to solve the questions of the drawing techniques for design and construction. 4) The technicians of drawing were the painters who were trained in a government organization in charge of royal paintings. In the future, research of this area should be continued in to deepen study on drawings as historical materials. This research provides meaningful of guidance in the analysis of historic drawing paintings.

• Transactions of Materials Processing
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• v.14 no.7 s.79
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• pp.607-612
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• 2005

In this paper, warm deep drawing process with local heating and cooling technique was attempted to improve the formability of AZ31 magnesium alloy which is impossibly to form by conventional methods at room temperature by finite element method and experiment. For FE analysis, in first model with considering heat transfer, both die and blankholder were heated to 573K while the punch was kept at room temperature by cooling water. Also distribution of thickness and von Mises stress at room temperature and 498k for warm deep drawing were compared by FEM. Uniaxial tension tests at elevated temperature were done in order to obtain the temperature dependence of material constant under temperature of $293K\~573K$ and cross head velocity of $5\~500mm/min$. The phenomenological model for warm deep drawing process in this work was based on the hardening law and power law strain rate dependency. Deep drawing experiment were conducted at temperatures of room temperature, 373K, 423K, 473K, 498K, 523K, and 573K for the blank and deep drawing tools(holder and die) and at a punch speed of 10mm/min.

• Journal of KIBIM
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• v.13 no.4
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• pp.85-95
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• 2023

In the process of creating drawings based on Building Information Modeling (BIM), automatically generated annotations can cause interference issues depending on the drawing type. This study aims to develop an algorithm for repositioning annotations using genetic algorithms to minimize such interferences. To achieve this, the Application Programming Interface (API) of BIM software was used to analyze data extractable from BIM drawing files. The process involved defining drawing data related to annotation repositioning, preprocessing this data, and deriving optimal placement coordinates for the annotations. Furthermore, applying the developed algorithm to the preliminary design drawings of small and medium-sized neighborhood facilities resulted in approximately a 95.37% decrease in annotation interference, indicating that the proposed algorithm can significantly enhance productivity in BIM-based drawing tasks.

• Transactions of Materials Processing
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• v.19 no.8
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• pp.508-516
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• 2010

Thickening process in sheet metal forming is being increased to improve the strength as well as to reduce manufacturing process such as welding. This process can make it possible to obtain part locally thicker than that of initial sheet thickness. In this study, design method for manufacturing the component which has double sinks with local thickened wall is proposed. Deep drawing and upsetting processes are applied in order to form double sinks and thicken its walls. Used material is SPHC440 with the thickness of 2.0mm and initial blank size is determined on the basis of the final product. Distance between the center of double sinks and first drawing ratio to avoid fracture are the most significant factors during deep drawing. FE-analysis is implemented in order to determine the appropriate values. Progressive die is designed based on the proposed method and FE-analysis. As a result of experiment, locally thickened component can be manufactured, which has double sinks with the thickness about 3mm at the corner and wall.

• Transactions of Materials Processing
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• v.29 no.2
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• pp.89-96
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• 2020

The finite element method has been widely applied in the sheet metal forming process. However, the finite element method is computationally expensive and time consuming. In order to tackle this problem, surrogate modeling methods have been proposed. An artificial neural network (ANN) is one such surrogate model and has been well studied over the past decades. However, when it comes to ANN with two or more layers, so called deep neural networks (DNN), there is distinct a lack of research. We chose to use DNNs our surrogate model to predict the behavior of sheet metal in the deep drawing process. Thickness variation is selected as an output of the DNN in order to evaluate workpiece feasibility. Input variables of the DNN are radius of die, die corner and blank holder force. Finite element analysis was conducted to obtain data for surrogate model construction and testing. Sampling points were determined by full factorial, latin hyper cube and monte carlo methods. We investigated the performance of the DNN according to its structure, number of nodes and number of layers, then it was compared with a radial basis function surrogate model using various sampling methods and numbers. The results show that our DNN could be used as an efficient surrogate model for the deep drawing process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2653-2663
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• 1994

The design of sheet metal working processes is based on the knowledge about the deformation mechanism and the influence of the process parameters. The typical geometric process parameters are the die geometry, the initial sheet thickness, the initial blank shape, and so on. The initial blank shape is of vital importance in the most sheet metal forming operations, especially in the deep drawing process, since the forming load and the strain distribution are significantly affected by the shape of an initial blank. The influence of the initial blank shape on a square cup deep drawing process is investigated by the numerical simulation and the experiment. The numerical simulation is carried out by a modified membrane finite element method which takes bending deformation into account. The numerical and experi-mental results show that the initial blank shape have strong influence on the forming load and the strain distribution. The numerical results are compared with the experimental results and other numerical results which are calculated with the membrane theory.

• Journal of computational fluids engineering
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• v.18 no.4
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• pp.69-73
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• 2013

Mass manufacturing of optical fiber includes the process of very thin glass fiber drawing by heating and softening the high purity silica preform and applying the draw tension on the softened tip of preform neck-down profile in a draw furnace. In this computational study, this process is numerically modeled with simplified geometry of the draw furnace which is comprised of essential parts such as concentric graphite heater, muffle tube, and insulation surrounding the heater. The iterative computational scheme is employed between one-dimensional model of neck-down profile prediction and two-dimensional axisymmetric thermo-fluid CFD computation of radiative heating and working gas convection. The computational results show the experimentally observed neck-down profile in heated section of preform, while yielding the reasonable values of draw tension and heater wattage. Also, this study analyzes and discusses the effects of heating conditions such as heater length and temperature on several important aspects of glass fiber drawing process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.407-410
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• 2005

The drawability of AZ31B magnesium sheet is estimated according to the variable temperatures (200, 250, 300, 350 and $400^{\circ}C$), forming speed (20, 50, 100 mm/min), thickness (0.8, 1.4 t), blank holding force (1.0, 1.4, 1.7kN). The deep drawing process (DDP) of circular cup is used in forming experiments. The results of deep drawing experiences show that the drawability is well at the range from 250 to $300^{\circ}C$, 50mm/min forming speed and 1.4kN blank holding force. The 0.8t magnesium sheets were deformed better than 1.4t. BHF was controlled in order to improve drawability and protect the change of cup thickness. When BHF was controlled, tearing and thickness change were decreased and LDR. was improved from 2.1 to 3.0.

• Journal of Fashion Business
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• v.1 no.1
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• pp.84-98
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• 1997

This study is to develop a fashion drawing education program which is based on the theory of 'Split-brain' by Roger W. Sperry and 'Drawing on the Right Side of the Brain' by Betty Edwards. Students in Fashion Design start their training by developing a foundation in drawing and studing the tools, materials and methods of the Industry. Ideas are then developed on paper, later translated into three-dimensional shapes and finally into finished garments. Fashion drawing and design techniques train the hand and eye to all the nuances of fashion design and illustration. Fashion drawing course deals with the sketching of fashion models for the purpose of understanding the model figure, basic anatomy, movement and figure attitudes. Having mastered the basic skills, students take advanced drawing course which is developing awareness of design, needs, of fashion market' using various media for the purpose of developing a designer's sketch, with emphasis on the drawing and designs. Featured aspects of this study include the following; 1. Drawing the negative space; basic visual concepts 2. Contour drawing; constructs, visual measurement, movement 3. Model drawing; the classical method, proportion, symmetry. The primary aim of this study is to develop a sensitive, animated line based on observed form. It is important to let the students Imagine that they are actually touching the model, for in this way they can benefit from simulating the child's learning process. Instead of actually touching the model they are using their eyes as an extension of their sense of touch.