• Transactions of Materials Processing
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• v.24 no.6
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• pp.425-430
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• 2015

In the current paper, the effects of initial slug design on the earring of an Al rectangular battery case manufactured by impact extrusion were studied. During impact extrusion, non-uniform metal flow between the long and the short sides of the battery case leads to earring, which is subsequently trimmed. Process parameters such as friction, aspect ratio of the battery case, the die shape and the forming temperature tend to induce earring because they cause greater non-uniform metal flow. Large aspect ratio of the battery case and high friction between slug and die can greatly affect the earring of a rectangular battery case. To make a rectangular battery case without earring, it is necessary to control metal flow uniformly during impact extrusion. One of the ways to reduce the earring is to control the metal flow of slug at the initial upsetting stage. To analyze the effects of the initial slug design on earring, FE analysis was conducted using DEFORM 3D. Two types of initial slug designs were evaluated where volume was removed along either the width or thickness directions. The results show that the initial slug design can be effective in adjusting the uniformity of metal flow.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.4
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• pp.387-394
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• 2019

This paper presents an analytical study on the strength and stiffness of various types of truss structures. The applied models are triangular-like opened truss-wall triangular model (OTT), closed truss-wall triangular model (CTT), opened solid-wall triangular model (OST), and hypercube models defined as core-filled or core-spaced cube. The models are analyzed by numerical model analysis using DEFORM 2D/3D tool with AISI 304 stainless steel. Then, the ideal solutions for stiffness and strength are defined. Finally, the relative elastic modulus of the core-spaced model is obtained as 0.0009, which is correlated with the cancellous bone for the relative density range of 0.029-0.03, and the relative elastic modulus for the core-filled model is obtained as 0.0015, which is correlated with cancellous bone for the relative density range of 0.035-0.036. For the relative compressive yield strength, the OTT reasonably agrees with the cancellous bone for the relative density of 0.042 and the relative compressive strength of 0.05. The CTT and OST are in good agreement at the relative density of 0.013 and the relative compressive yield strength of 0.002. The hypercube models can be used for the cancellous bone for stiffness, and the triangular models can be used for the cancellous bone for strength. However, none of the models can be used to replace the compact bone because it requires much higher stiffness and strength. In the near future, compact bone replacement must be further studied. In addition, previously mentioned models should be developed further.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.7
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• pp.1111-1125
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• 2010

Study is a basic analysis of a future virtual clothing system based on a comparative analysis of all the shirring, using a 3-dimensional apparel cad system. Frilled skirts shirred at the lower hemline were the subject of this study for a comparison of expression and shape of shirring. It compared the silhouette and details expressed in virtual and real skirts made of woolen fabrics and polyester satin, with different widths (1.5, 2 and 2.5 widths). It was found that the virtual skirt could not express shirring as exquisitely as the real skirt due to fabric thickness and other fabric characteristics. In addition, the increase in widths caused the frill shape to deform badly. In the case of a virtual skirt made of polyester satin, the increased multiplication factor let the frill spread out sharply (unlike the real skirt). Simulated skirts of polyester satin and woolen spread out to the sides with the sidelines of their frills hanging down markedly (unlike the real cloths) when the frills changed from 1.5 widths to 2 widths. When it came to the virtual skirt, side-line from the hip down all the way short of frill contorted with the wrinkle multiplication factor of 2 and 2.5 widths. This phenomenon was more notable in polyester satin skirts than in woolen skirts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.653-659
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• 2017

In this study, the complex forging process of an outer support ring was developed and the prototype was manufactured. The current process, hot forging and MCT machining, has a disadvantage of excessive material removal rates and longer machining hours. To overcome this disadvantage, a general shape is given through hot forging and the precision is achieved through cold forging. The complex forging process was developed with the minimal machining process. Forging analysis was carried out to design a forging process using the commercial program, Deform-3D. The hot and cold forging processes were set up based on the analyzed result. The mold and prototype were manufactured. Hardness, surface roughness, internal defect, the grain low line of the prototype were evaluated. The results showed no particular problems, and there were no problems in mass production. Using complex forging, the material was reduced by approximately 27 % compared to the process using hot forging and MCT machining. In addition, the production speed was improved 2.15 fold compared to that of hot forging and MCT machining. Through this study, a cost-effective process and mold design technology were established, which is expected to have positive effects on other related automotive parts production.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1587-1590
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• 2005

A rigid-plastic finite element analysis for the die forging process of a socket ball joint, which is used in the transportation system, was carried out. And also with the results, the elastic stress analysis for the forging die was performed in order to get basic data for the die life prediction. The die fatigue life prediction was simulated using Goodman's and Gerber's equation. The prediction technique for the fatigue life of a forged product, the socket ball joint, using DEFORM-3D is presented and the results are commented upon. Archard's wear model was used for the wear simulation and then the wear simulation and then the wear quantity was quantity was evaluated using volume. In order to prove the wear simulation results to be reliable, wear quantity of the real forging die set in used a forging factory was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.100-110
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• 2000

In practical design of girder bridges or reinforced concrete slab bridges with T-type piers, it is usually assumed that vertical movements of superstructures are completely restrained at the locations of bearings(shoes) on a cap beam of the pier, The resulting vertical reactions are applied to the bearing for the calculation of bending moments and shear forces in the cap beam. However, in reality, the overhang parts of the cap beam will deform under the dead load of superstructures and the live load so that it may act as an elastic foundation. Due to the settlement of the elastic foundation, the actual distribution of the reactions at the bearings along the cap beam may be different from that obtained under the assumption that the vertical movements are fixed at the bearings. In the present study, investigated is the effects of elastic deformations of the T-type pier on the distribution of reactions at the bearings along the cap beam through 3-dimensional finite element analysis. Herein, for this purpose the whole structural system including the superstructure and piers as well is analyzed. It appears that the conventional practice which neglects the elastic deformations of the cap beam exhibits considerably different distributions of the reactions as compared with those obtained from the present finite element analysis. It is, therefore, recommended that in order to assess the reactions at bearings correctly the whole structural system be analyzed using 3-dimensional finite element analysis.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.160-166
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• 2010

In this paper, the process parameters of thread rolling were designed based on the numerical analysis results. Firstly, the effective analysis conditions that guarantee the reliability of the analysis results were found. To find the effective analysis conditions, the analyses were carried out for various numbers of teeth. And then, the effects of the process parameters such as tool shape and temperature on the thread rolling performance were investigated. The formability in thread rolling process was evaluated in terms of Cockcroft-Latham damage value. In order to evaluate formability, Cockcroft-Latham damage value was normalized by the critical damage value which was obtained from the analysis of uniaxial tensile test. The analyses were carried out using DEFORM-3D. The results showed that the flank angle and crest round had an effect on the thread rolling load. It was also shown that temperature had significant effects on the effective strain distribution, rolling load, and damage. With the reduced formability of stainless steel at higher temperature, it was shown that the normalized damage values increased as the process temperature.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.173-177
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• 2013

The purpose of this paper is to investigate the influences on mechanical properties of two-stroke cycle motor pistons manufactured by casting, conventional forging and powder forging, through the comparison of characteristics, merits and disadvantages of each forming technology. For each forming technology, the optimal process parameters were determined through the experiments for several conditions, and microstructure, hardness, tensile strength and elongation of pistons are compared and analyzed. In conventional forging process, material temperature was $460^{\circ}C$ and the die temperature was $210^{\circ}C$ for the Al 4032. The optimal condition was found as solution treatment under $520^{\circ}C$ for 5 hours, quenching with $23^{\circ}C$ water, and aging under $190^{\circ}C$ for 5 hours. In powder forging process, the proper composition of material was determined and optimal sintering conditions were examined. From the experiment, 1.5% of Si contents on the total weight, $580^{\circ}C$ of sintering temperature, and 25 minutes of sintering time were determined as the optimal process condition. For the optimal condition, the pistons had 76.4~78.3 [HRB] of hardness, and 500 [MPa] of tensile strength after T6 heat treatment.

• Fashion & Textile Research Journal
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• v.10 no.3
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• pp.329-334
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• 2008

The purpose of this research is to develop the design, pattern and size system of brief as a measurement garment in order to obtain more precise silhouettes and sizes of the body in 3D measurements. The results of this research are as follows: First, nylon/lycra materials which elasticity is equivalent to 18%(wale) and 27%(course), were selected as a material for briefs to minimize possible error in measurement and deformation of body shape caused by looseness or tightness in its measured parts. And T-back style design was selected, of which briefs neither deform human body nor cause overlapping or excessive tightness when was put on the measurement garment over it. Second, different darts for men and women were adopted into the pattern in consideration for the shape of hip. Third, the waist band of briefs was located between the waistline and abdominal girth line so that it didn't interfere with measurement, and using a wide band of 40mm minimized the tightness of the human body. In addition, the stitch lines and sewing procedure were simplified to minimize the deformation of body shape resulting from inseams and stitch lines. Finally, for the size of briefs, 6 cm intervals were set on the basis of the waist girth and 8 kinds for men and 6 kinds for women were selected in descending order of appearance rate by the interval sections. English T meaning T-back design and numbers representing the waist girth were marked in parallel for the name of size.

• Journal of the Korea Computer Graphics Society
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• v.27 no.5
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• pp.1-11
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• 2021

The purpose of our research is to efficiently deform a 3D models which is composed of a triangular mesh and a skeleton. We designed a novel inverse kinematics (IK) solver that calculates the updated positions of mesh vertices with fewer computing operations. Through our user interface, one or more markers are selected on the surface of the model and their target positions are set, then the system updates the positions of surface vertices to construct a deformed model. The IK solving process for updating vertex positions includes many computations for obtaining transformations of the markers, their affecting joints, and their parent joints. Many of these computations are often redundant. We precompute those redundant terms in advance so that the 3-nested loop computation structure was improved to a 2-nested loop structure, and thus the computation time for a deformation is greatly reduced. This novel IK solver can be adopted for efficient performance in various research fields, such as handling 3D models implemented by LBS method, or object tracking without any markers.