• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.2
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• pp.57-66
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• 2015

The purpose of this study was to improved the durability of a improved movable weir by replacing the improved movable weir's metal gate with a hybrid steel/glass fiber reinforced polymer composites panel gate. Because the metal gate of a improved movable weir is always in contact with water, its service life is shortened by corrosion. This study made four type of hybrid steel/glass fiber reinforced polymer composites panel gate with different steel gate surface deformation (control, sand blast, scratch and hole), flexural. Fracture properties tests were performed depending on the steel gate surface deformation. According to the test results, the flexural behavior, flexural strength and fracture properties of hybrid steel/glass fiber reinforced polymer composites panel gate was affected by the steel panel gate surface deformation. Also, the sand blast type hybrid steel/glass fiber reinforced polymer composites panel gate shows vastly superior flexural and fracture performance compared to other types.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.3
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• pp.50-59
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• 1999

This paper is concerned on the generation of an optimal section of wing in ground effect by a SQP method which is one of nonlinear optimization techniques. A potential panel method is used for the flow analysis and the ground effect is taken into account by an image method. The numerical method is first verified by an inverse problem where a shape of wing section is sought for the prescribed pressure distribution. The purpose of the present paper is to generate a wing section which can give a maximum lift subjected to the design constraints including the height stability which is important in the WIG design. The effect of the tail wing is also included.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.3
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• pp.122-133
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• 1999

Overlap, excessive wide gaps, and errors between blocks during erection process increases cost and man-hour. In this paper, a system to simulate the assembly process is suggested and a plane block assembly of welding deformation with gravity is simulated in consideration of assembly order, deformations and errors occurring in the cutting and forming processes are not considered and welding deformations are acquired by equivalent stiffness and load method from experiments and hull double bottom plane block is assembled on a assembly order by panel method. It is certified that according to the order of assembly, intermediate product shape affects rigidity which affects welding deformations. Assembly order must be considered in the assembly process. It is certified that the gravity has important role in the assembly process.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.64.1-64.1
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• 2011

LCD 디스플레이 등에 사용되는 글래스 패널 위에 bare si die를 직접 실장하는 COG 플립칩 패키지의 경우 Au 범프와 ITO 패드 간의 전기적 접속 및 접합부 신뢰성 확보를 위해 접속소재로서 ACF (anisotropic conductive film)가 사용되고 있다. 그러나 ACF는 고가이고 접속피치 미세화에 따라 브릿지 형상에 의한 쇼트 등의 문제가 발행할 수 있어 NCP (non-conductive paste)의 상용화가 요구되고 있다. 본 연구에서는 NCP를 적용한 COG 패키지에 있어서 온도, 압력 등의 열압착 본딩 조건과 NCP 물성이 Au-ITO 접합부의 전기적 및 기계적 특성에 미치는 영향을 조사하였다. NCP는 에폭시 레진과 경화제, 촉매제를 사용하여 다양하게 포뮬레이션을 하였고 DSC (Differential Scanning Calorimeter), TGA (Thermogravimetric Analysis), DEA (Dielectric Analysis) 등의 열분석장비를 이용하여 NCP의 물성과 경화 거동을 확인하였다. 테스트 베드는 면적 $5.2{\times}7.2\;mm^2$, 두께 650 ${\mu}m$, 접속피치 200 ${\mu}m$의 Au범프가 형성된 플립칩 실리콘 다이와 접속패드가 ITO로 finish된 글래스 기판을 사용하였다. 글래스 기판과 실리콘 칩은 본딩 전 PVA Tepla사의 Microwave 플라즈마 장비로 Ar, $O_2$ 플라즈마 처리를 하였으며, Panasonic FCB-3 플립칩 본더를 사용하여 본딩하였다. 본딩 후 접합면의 보이드를 평가하고 die 전단강도로 접합강도를 측정하였다.

• Journal of Ocean Engineering and Technology
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• v.27 no.4
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• pp.62-67
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• 2013

In this paper, the wave run.up on a vertical cylinder is presented. Various cross sections of a cylinder were simulated using the panel method for various wave periods. Two.dimensional model tests were performed in a wave flume. The simulation results are compared with the test results. The simulation is based on the linear diffraction theory.

• Composites Research
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• v.15 no.1
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• pp.1-8
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• 2002

In this study, the flutter analysis for a rectangular box wing and an actual fighter wing with composite shin, aluminum spar and aluminum rib has been conducted. A conservative 3D wing-box model of an actual wing is modeled by MSC/PATRAN and the corresponding free vibration analysis has been performed by MSC/NASTRAN. The finite elements of membrane, rod and shear panel are used. Using the practical ply angles, various composite laminates are composed and analysed. The DLM code which is linear aerodynamic theory in frequency domain is applied to calculate unsteady aerodynamic pressure in subsonic flow region and the V-g and p-k methods are applied to obtain the solution of aeroelastic governing equation in frequency domain.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.75-78
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• 2007

In this study, low velocity impact analysis on Turbo Fan Engine composite sandwich structure was performed. Sandwich structure configuration is made of carbon/epoxy face sheets and foam cores. For validating study, the results of an experimental and of a Finite Element Method analysis were compared previously. From the Finite Element Method analysis results of sandwich panel, it was confirmed that the result of analysis was reasonable. Impactor velocity to initiate damage was estimated, and in order to investigate the damage at the predicted velocity, impact analysis using Finite Element Method was performed. According to the impact analysis results of sandwich panel, it was confirmed that the damage was generated at the estimated impact velocity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.12-13
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• 2020

Free-form buildings usually have large curved shapes on the outside. In order to construct this curved shape, the exterior of the building must be divided into easy-to-manufacture shapes, and the segmented panel is called the FCP(Free-form Concrete Panel). These FCPs have different shapes and cannot reuse molds. To solve these problems, the researchers developed FCP manufacturing equipment to manufacture a mould of FCP. However, the developed equipment alone cannot completely manufacture FCP's mould. This is because there is no mould to implement side of FCP. Therefore, it is necessary to develop a side form of FCP that can be applied to FCP manufacturing equipment. To this end, this study analyzes the basic requirements that side mould should have before developing side mould.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.21-22
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• 2023

In order to manufacture high-quality free-form concrete panel (FCP), it is necessary to analyze the limitations of free-form silicone mold (FSM) and conduct technology development research. Currently, the FSM used in FCP manufacture is classified into a side silicon mold(SSM) and a lower silicon mold(LSM). In this study, the limitations of each silicon mold were analyzed and solutions were proposed. In the case of side silicon mold, there is a limit to cannot supporting the side pressure of concrete. Therefore, a mold stacking method was proposed, and at the same time, a process of correcting the movement value of the rod was proposed. In the case of the lower silicon mold, there is a limit to completely implementing the design shape. Therefore, a real-time scanning method and a process of displaying FCP shape coordinates were proposed. The results of this study are expected to be used as basic data for manufacturing high-quality FCP.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.308-313
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• 2014

Recently, for longevity of resident building, the main trend is that the change of the inside space organization of resident building from wall construction to rhamen construction, which resulted in increase in use of lightweight composite panel. Thus, in this study, authors analyzed the engineering property of oxide of magnesium depending on the magnesium chloride addition ratio. The results of this research is expected to contribute on providing a fundamental material for the surface materials of lightweight composite panel. As the result of the experiment, as fluidity increased, air content decreased and initial set and final set as the magnesium chloride addition ratio increase. In the aspect of flexural strength and compressive strength, the test specimen showed the highest strength at 40% of the magnesium chloride addition ratio. At 20% of the magnesium chloride addition ratio, the test specimen showed the lowest water absorption rate. As the magnesium chloride addition ratio increases, the expansibility tends to increase as well in the aspect of shrinkage strain. After observing microstructure, we can see hydration products in the form of needle. It appeared high flexural strength because the hydration products have mineral fibrous tissue shape, which also contribute to the cause of the expansibility.