• Journal of Environmental Science International
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• v.5 no.4
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• pp.495-511
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• 1996

The quantitative study of the groundwater contamination in a porous media is a difficult task. For complex problems, numerical solutions are the most effective means to study the movement of contaminants in the groundwater, The solute transport model used in this study has proved to be an efficient tool to model contaminant transport for complex problems. The model demonstrates its effectiveness in reproducing the coniamination by ihlorides of the groundwater at the landfill site due to leachath from the wastes. It describes the two dimentional solute transport and alteration of the water quality and forecasts the contamination for different management alternatives of the landfill. The model also indicates how the groundwater contamination can be contained within the lower site if a barrier is constructed downstream of the disposed wastes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.771-774
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• 2000

Coiling processes of filaments need precise work and standardization. It is important to maintain equal pitch of filaments. Uniform pitch of filaments is one of the dominant elements of life time and efficiency of bulbs. First coiling process of filament wires is modeled by nonlinear contact problem between filaments and mandrel. Analysis of coiling process using finite element method is conducted to consider manufacturing parameters and pitch distance is calculated under the given conditions. Also image detecting system is developed to inspect uniformity of pitch. This system will be used to inspect quality of filaments during coiling processes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.341-344
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• 2006

Finite element analysis and verification experiments were performed in order to find cause of defects such as folding and improper radius around the root area of the thread rolled stud bolts. Thread rolling experiments under several conditions were also carried out to understand the effect of process parameters, such as the rotation speed of the dies and the hardness of the work pieces, on the product quality. Folding defects at the top of thread are attributed to the higher hardness of the work piece and higher rotation speed of the rolling die. It was also found that the radius of screw mainly determined by the radius of the die.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.100-107
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• 2005

The objective of the study is to improve the quality of wheel bearing hub by the rigid-plastic finite element analysis and the response surface methodology. The rigid-plastic finite element codes, AFDEX-2D and DEFORM-3D, were used to analyze the two-dimensional and three-dimensional forging processes, respectively. The response surface analysis is used to find the minimum underfill by the variation of design variables such as the height of billet after upsetting and punch angles of blocker dies. The metal flow of forged product shows good agreement with the results from 2D and 3D analysis. Also, the quality of the wheel bearing hub has been improved by the optimization of design variables and the machining time has been reduced by the machining allowance.

• Transactions of Materials Processing
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• v.12 no.4
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• pp.340-347
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• 2003

In the rigid-plastic finite element simulation of hot forging processes using hexahedral mesh, remeshing of a flash is important for design and control of the process to obtain desirable defect-free products. The mesh compression method is a remeshing technique which enables the construction of an effective hexahedral mesh in the flash. However, because the mesh is distorted during the compression procedure of the mesh compression method, when it is used in resuming the analysis, it causes discretization error and decreases the conversance rate. Therefore, mesh smoothing is necessary to improve the mesh quality. In this study, several geometric mesh smoothing techniques and optimization techniques are introduced and modified to improve mesh quality. Then, the most adaptive technique is recommended for the mesh compression method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.11
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• pp.617-624
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• 1999

The spiral type thin-film inductor performed in high frequency at 2-5[MHz] range is analyzed by 2-dimensional Finite Element Method(2D FEM). The features of micro thin-film inductor have complicated electromagnetic phenomenon such as skin effect, proximity effect and magnetic saturation. To develope miniatured magnetic device considering these features, it is important to predict the property of the thin film inductor according to design parameter. In this paper, we present the 2D FEM analysis for the spiral type thin film inductor. The characteristics of inductor from point of view of inductance, resistance and quality factor are studied according to design parameter and various pattern construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.1
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• pp.157-162
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• 1999

KS-code(KS B 0896) for nondestructive ultrasonic testing judge the quality level by ratio of flaw size to plate thickness only. But stress distributions using finite element analysis show that location of the flaws are more important than the flaw size. So, KS-code should take into account of flaw location for judging the quality level of welded steel structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.857-860
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• 2005

A guitar pickup transforms the vibration of strings to the electric signals, and deliveres them to an amplifier. A piezo pickup has interference problem between strings. The paper aims to improve sound quality for an electro-acoustic guitar through the finite element analysis. Firstly the conventional pickup is modeled and analyzed with a commercial program called ANSYS. It is obvious that there exists interference between the strings. The structural modification of the pickup is performed, based on the beam theory The modified structures are suggested, modeled and analyzed. Then the result are compared with those in the conventional pickup. It can be concluded that the interferences with the modified structures are much less than those with the conventional structure.

• Transactions of Materials Processing
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• v.33 no.1
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• pp.43-49
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• 2024

A high strength steel sheet (HSSS) has widely used to improve the specific rigidity of parts and the safety of the passenger in automotive industries. However, the HSSS is difficult to manufacture precise parts through a forming process due to the reduced elongation and the increased elastic recovery. The goal of the paper is to investigate the improved design of bending dies for DP590 HSSS. The over forming type bending dies with cam systems added to the side of the formed part is proposed to improve the quality of the part. The effects of the die design and the forming parameter on formability and elastic recovery characteristics is examined using finite element analyses (FEAs). From the results of FEAs, proper die design and forming parameters are predicted.

• Computational Structural Engineering
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• v.3 no.2
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• pp.117-128
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• 1990

This study was intended to provide efficient algorithms for high quality postprocessing on the basis of microcomputers with limited capacity and functionality. Improved methods of postprocessing including stress contouring, internal force diagraming, and displacement animation, were proposed and implemented into a new finite element system. Visualization of three-dimensional structural behaviors was treated with special emphasis.