• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.197-204
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• 2006

Recently, in order to realization of construction and economical saving, various studies are progressing. Also, the study on RCS system which is consisted of reinforced concrete column and steel beam is progressing actively. Actually, however, resisting mechanism of panel zone is influenced by transverse beams when the stress transfers inner panel to outer panel but existing literature didn't reflect the effect of transverse beams. This paper is to analyze the test result of five inner beam-column joints specimen with a variable such as web, flange thickness of transverse beam and face bearing plate(FBP) for RCS systems were tested under cyclic loadings conforming to NEHRP recommendation to investigate the effect of transverse beams and the structural performance of beam-column joints. From the test result, it was shown that transverse beams are effective to enhance the shear strength and structural performance of beam-column joints.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.343-346
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• 2004

In recent years, various forms of indentation testing have been increasingly used to determine the material properties of specimens. This technique, particularly the nano-indentation method , has been extended to the testing of coating systems in order to calculate the individual properties of the thin coatings and the substrates. However, the interpretation of the test data to achieve this is complex and continues to be a widely studied subject. Based on the finite element method of coated surfaces indented by a Berkovich diamond tip, this paper describes methods for combining FEM and experimental indentation testing to determine coating modulus and hardness independent of substrate effects. Using this proposed methodology, testing and FEM to measure coefficients of friction of sheet steel for outer panel were studied.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.41-49
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• 2007

More diversified and strengthened safety regulations require higher safety vehicle with less weight. The structural foam can play a role for restraining section distortion of main body members undergoing bending collapse at vehicle crash. In this study, using structural foam modeling technology, validated in previous work, the bending collapse characteristics were evaluated for two types of circular and actual vehicle body frame sections. With changing the foam filling method, outer panel thickness and section shape, load carrying capability and absorbed energy were observed. The results indicate valuable design strategy for effectively elevating bending collapse performance of body members with foam filled.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.894-897
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• 2006

The detailed studies regarding to the front and rear panel geometries and optical properties of composed layers were needed to improve the luminance and efficiency. 3-dimensional optical code can be used to analyze the variation of geometries and the changing of optical properties. The visible light distributions and illuminance results were simulated depending on the bus electrode position, ITO geometries and optical properties of dielectric layer. As the ITO area was decreased and the bus electrode was located at the outer part of cell, the illumination was increased. And we could find quantification which is related between dielectric layer and visible light distribution of PDP cell.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1474-1486
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• 1990

The frictional characteristics of galvanized sheet steels(GA, EG, EGF, EGN) for automobiles were studied and compared with that of cold rolled sheet steel. A draw bead tester which simulates metal flow through a draw bead in stamping die face was used to measure coefficients of friction of galvanized sheet steels for four kinds of lubricants. Stamping formability of galvanized sheet steels for quarter outer panel was examined. The results show that stamping formability and friction characteristics were mainly influenced by the nature of zinc coating, surface roughness and micro hardness of coated layer, and proved to be very sensitive to the lubricant used.

• Transactions of Materials Processing
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• v.10 no.2
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• pp.91-100
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• 2001

A sectional FEA program is developed lot analyzing forming processes of sandwich sheets, which are intensively used recently as a lightweight material of an automobile body. The aluminum sandwich sheet consists of two aluminum skins and a polyprophylen core in between. The aluminum sandwich sheet is dominantly effected by the bending effects in small radius of curvature, so that an appropriate description of bending effects is required to analyze the forming processes. For the evaluation of bending effects, the bending equivalent forces are calculated from the bending moment computed using the curvature of the tool and are added to the membrane stretch forces. To verify the validity of the developed program the sectional FEA results in stretch/draw forming Processes of a square cup and draw forming Processes of an outer hood panel were compared with the measurements.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.06a
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• pp.68-71
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• 2006

Traditional section-based method develops blank along section planes and find trimming line by generating loop of end points. This method suffers from inaccurate results for regions with out-of-section motion. In this study, new fast method to find feasible trimming line is proposed. One step FEM is used to analyze the flanging and incremental development method is proposed to handle bad-shaped mesh and undercut part. Also in order to remedy mesh distortion during development, energy minimization technique is utilized. The proposed method is verified by shrink/stretch flange forming and successfully applied to the complex industrial applications such as door outer flanging process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.68-75
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• 2008

This paper investigates the correlation between surface roughness and gloss of aluminium sheet painted waterborne paint. One customer criterion of automotive quality is the as-painted appearance of the final products. Especially, the current emphasis on control of surface roughness of sanded aluminium sheet has been prompted by the automotive industry's concern with the as-painted appearance. because the influence of such characteristics on paintability, and painted appearance is important in defining outer panel requirements for automobile. This paper is dedicated primarily to the issue of painted appearance and reviews for improvement of roughness. The conclusions are obtained as follows ; 1) Painted aluminium sheet appearance is strongly affected by surface roughness of base-metal and influenced by sand paper and sanding method. 2) The painted appearance of aluminium sheets was determined and related to surface roughness parameters, combination of sand paper.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1277-1282
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• 2008

Recently LCD panels have becom very important components for portable electronics. In the high density interconnection material, ACF's are used to connect the outer lead of the tape automated bonding to the transparent indium tin oxide electrodes of the LCD panel. ACF consists of an adhesive polymer matrix and randomly dispersed conductive balls. In this study, we analyzed Failure Mode / Mechanism of ACF which is identified Conductive ball Corrsion, Delamination, Crack and Polymer Expansion / Swelling. In ALT(Accelerated Life Test), we select primary stress factors as temperature and humidity. As time passes by, an increase of connection resistance was observed. In conclusion, we have found that high temperature / humidity affects the adhesion.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.339-347
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• 2000

For the successful forming of tailored blank, it is important to control the deformation of the stretch flange mode, which is strong1y dependent upon the location of weld line and blank shape. In order to investigate the effects of tailored blank design factors on the stretch flange forming, we made the model die which can simulate stretch flange mode. Taguchi method was employed to analyze the sensitivity of blank design factors for the forming of tailored blank. From the results of experiment S/N ratios were calculated and using Variance Analysis, significance of parameters and optimal condition of each factors were extracted. Based on these analyses, the weld line height and the strength ratio and the arc center height were selected as effective parameter. The analysed result was practically applied for Side outer panel stamping process.