• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.159-163
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• 2003

This study is object to minimum weight design of stiffened laminated composite flat panel. Various buckling load factors are obtained for stiffened laminated composite flat panels with rectangular type longitudinal stiffeners and various aspect ratios, which are made from Carbon/Epoxy USN150 prepreg and are simply-supported on four edges under uniaxial compression.

• Steel and Composite Structures
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• v.14 no.2
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• pp.121-132
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• 2013

This paper deals with multiobjective optimization of symmetrically laminated composite angle-ply annular sector plates subjected to axial uniform pressure load and thermal load. The design objective is the maximization of the weighted sum of the critical buckling load and fundamental frequency. The design variable is the fibre orientations in the layers. The performance index is formulated as the weighted sum of individual objectives in order to obtain the optimum solutions of the design problem. The first-order shear deformation theory is used for the mathematical formulation. Finally, the effects of different weighting factors, annularity, sector angle and boundary conditions on the optimal design are investigated and the results are compared.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.349-354
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• 2002

Stud penetrate welding is an important item of composite floor in modern steel structure, especially in high-rise buildings. But it is difficult to get satisfied welding quality due to all kinds of factors. In this paper, the author put forward a new welding procedure named method of energy control through analysis and comparison of the wave curves of stud welding based on large amount of experiments and tests in laboratory and construction areas. The use of this welding procedure in some large engineering in recent years proved that this method is effective and practicable

• Journal of the Korean Ceramic Society
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• v.24 no.6
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• pp.593-601
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• 1987

A thermodynamic model to predict the stability of the water-in-oil type emulsion and the size of the droplets in stable emulsions was developed. Using this model, the effects of various factors government the droplet size in the metal salt solution-kerosene-span 80 system for the preparation of Al2O3-ZrO2 composite powders were investigated. It was shown that the given emulsion systems were thermodynamically unstable in every case but could be kinetically meta stable. When radius ofthe droplet was below nm, the increase in entropy change due to the configurational contribution of small droplets dominated the total free energy change for emulsification. The optimum conditions under which smaller deoplet was obtained were proposed and the validity of the model was proved with diameters of the droplet and composite powders experimentally determined.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.239-242
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• 2005

This paper introduced an approach of improvement of performance of Electric device for EMU type Train like as TTX. The electric equipments are characterized by insulation, Noise, cooling system etc. and Their weight arc decided by these factors. There are two kinds of power source in EMU train. First, DC voltage source, 1500 volt, 750 volt is used for subway system. Second, AC power source 25000 volt is applied to high speed train and existing main lines. Composite material has the protection of inrush current and high frequency noise. We can use this material to minimize weight of train. Additionally we can get energy saving when operator service TTX.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.28-33
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• 2011

In this paper, structural design for 2kW class composite blade is performed by using design of experiment(DOE). A full factorial design is applied to meet the design specifications at the manufacturing process. The analysis of variance(ANOVA) is made in order to determine the significance of effects in an analysis. Structural analysis by using of commercial software ABAQUS is performed to compute the displacement and safety factor of filament wound composite blade. The results show that the proposed method is suitable to analyze the factors at the design of wind turbine blade.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.698-707
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• 2003

A new quadratic response surface modeling method is presented. In this method, the incomplete small composite design (ISCD) is newly proposed to .educe the number of experimental runs than that of the SCD. Unlike the SCD, the proposed ISCD always gives a unique design assessed on the number of factors, although it may induce the rank-deficiency in the normal equation. Thus, the singular value decomposition (SVD) is employed to solve the normal equation. Then, the duality theory is used to newly develop the conservative least squares fitting (CONFIT) method. This can directly control the ever- or the under-estimation behavior of the approximate functions. Finally, the performance of CONFIT is numerically shown by comparing its'conservativeness with that of conventional fitting method. Also, optimizing one practical design problem numerically shows the effectiveness of the sequential approximate optimization (SAO) combined with the proposed ISCD and CONFIT.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.549-554
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• 2000

In this study, using linear and nonlinear deformation theories and by closed-form analysis and finite difference energy methods, respectively, various buckling load factors are obtained for stiffened laminated composite cylindrical panels with rectangular type longitudinal stiffeners and various longitudinal length to radius ratios, which are made from Carbon/Epoxy USN150 prepreg and are simply-supported on four edges under uniaxial compression, and then for them, buckling behavior design analyses are carried out by the nonlinear search optimizer, ADS

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.579-579
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• 2001

One of the most important factors for the clinical success of adhesive posterior restorations is marginal adaptation. This property is very closely related to mechanical properties and to the shrinkage behavior of composite materials. Most of modem composite materials are light-cured. This is why the first part of this lecture will be confined to our recent research on light curing, such as plasma polymerization, LED polymerization and the power of modem halogen lamps. In the second part of the lecture the shrinkage properties such as dimensional shrinkage and shrinkage forces of different light curing materials and during different curing procedures will be discussed. Finally, in the third part of the lecture, marginal adaptation before and after loading in different cavity classes and by using different restorative techniques and curing procedures will be presented. Data will also be given on wear resistance, abrasiveness against opposing cusps and postcuring of composite materials.(omitted)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.2
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• pp.144-150
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• 2003

Pleasantness or quietness becomes one of the most important factors for residential and office building designs recently. Especially for apartments, the noise generated by falling objects becomes a sensitive issue these days. To overcome the problem of the impact noise in apartments, the floor design has been changed. To reduce the transmissibility of the noise. composite floor structures ate devised and implemented for the construction of apartments. In this paper. the noise reduction) performance of a composite floor plate with holes is analyzed. Computational models for the structures are developed and its Performance is evaluated by using the finite element method. The results show that the noise can be significantly reduced with the multi-layer composite floor plates with holes.