• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.11
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• pp.447-455
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• 2017

At the modern industry, the composite material has been widely used. Particularly, the material of carbon fiber reinforced plastic hardened with resin on the basis of fiber is excellent. As the specific strength and rigidity are also superior, it receives attention as the light material. Among these materials, the carbon fiber reinforced plastic using carbon fiber has the superior mechanical property different from another fiber. So, it is utilized in vehicle and airplane at which high strength and light weight are needed at the same time. In this paper, the tensile property due to the fiber design is investigated through the analysis study with CT specimen composed of carbon plastic reinforced plastic. At the stress analysis of CFRP composite material with hole, the fracture trend at the tensile environment is examined. Also, it is shown that the lowest stress value happens and the deformation energy of the pre-crack becomes lowest at the analysis model composed of the stacking angle of 60° through the result due to the stacking angle. On the basis of this study result, it is thought to apply the foundation data to anticipate the fracture configuration at the structure applied with the practical experiment.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.616-622
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• 2001

In this paper, we analyzed the laminated composite sandwich plate structure of honeycomb core with changing values of the designing parameters. As a result, in designing parameters of that, the more height and thickness of the laminated composite plate's core, the more increase of natural frequency. The laminated angle has the maximum value when the plate of honeycomb core is join to opposite direction. This paper shows that the natural frequency of CFRP is higher than that of GFRP, and also impact strength marks maximum value in case of antisymmetry than symmetry of core. Also it shows that the mode shapes are various along with the angle-ply of laminated composite plate.

• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.139-147
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• 1993

Two sheets of high strength cement paste using ordinary Portland cement and water soluble polymer (polyacrylamide) were made by kneading with a twin roll mill. A carbon fiber layer out between two sheet of the cement paste, and then carbon fiber reinforced high strength cement composites were prepared by pressing them. The mechanical properties of the composites were investigated through the observation of the microstructure and the application of fracture mechanics. When the carbon fiber was added with 0.2 and 0.3wt% to the composites the flexural strength and Young's modulus were about 110∼116MPa and 74∼77GPa respectively, and critical stress intensity was about 3.14MPam1/2. It can be considered that the strength improvement of high strength cement fiber composites may be due to the removal of macropores and the increase of various fracture toughness effects; grain bridging, frictional interlocking, polymer fibril bridging and fiber bridging.

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.526-541
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• 2023

Wooden structures are widely used, particularly in earthquake zones, owing to their light weight, ease of application, and resistance to the external environment. In this study, we aimed to improve the mechanical properties of laminated timber beams using novel hybrid systems [carbon-fiber-reinforced polymer (CFRP) and wire rope]. Within the scope of this study, it is expected that using wood, which is an environmentally friendly and sustainable building element, will be more economical and safe than the reinforced concrete and steel elements currently used to pass through wide openings. The structural behavior of the hybrid-reinforced laminated timber beams was determined under the loading system. The experimental findings showed that the highest increase in the values of laminated beams reinforced with steel ropes was obtained with the 2N reinforcement, with a maximum load of 38 kN and a displacement of 137 mm. Thus, a load increase of 168% and displacement increase of 275% compared with the reference sample were obtained. Compared with the reference sample, a load increase of 92% and a displacement increase of 14% were obtained. Carbon fabrics placed between the layers with fiber-reinforced polymer (FRP) prevented crack development and provided significant interlayer connections. Consequently, the fabrics placed between the laminated wooden beams with the innovative reinforcement system will not disrupt the aesthetics or reduce the effect of earthquake forces, and significant reductions can be achieved in these sections.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.250-253
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• 2004

Emphasis has been placed on thin plate fabrication of plain woven carbon fabric reinforced Al matrix composites using liquid pressing process. The composite has potential applications for PDP rear plate. The process is to use the low pressure for infiltration of Al melt into plain woven carbon fabric as the Al melt is pressurized directly. The minimum pressure required for the infiltration was calculated from force balance equation, permeability measurements and compaction behavior of carbon fiber. Also, the melting temperature and the holding time have been optimized. In order to measure coefficient of thermal expansion (CTE) of the composites, the thermal strain measurement using strain gage was performed and the thermal conductivity of the composites was measured using laser flash method. The constituent materials of the composite are PAN type carbon fibers as reinforcements and 6061 Al alloys as matrices.

• Composites Research
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• v.35 no.5
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• pp.347-358
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• 2022

Carbon fiber is an excellent structural material, which has been proven in many industries, and the shipbuilding industry is no exception. In particular, in advanced maritime countries, special ships of the Navy and Coast Guard with carbon fiber composite hulls have already been deployed. In Korea, carbon fiber composite materials have been applied to a 10-ton class leisure craft or a 30-ton class patrol, but no research has been done on a hundred of tons or more vessels. In this study, the feasibility study of a 500-ton patrol vessel with a carbon fiber composite hull was conducted through an analysis of similar cases abroad. As a result, it was recognized that the developed hull can be reduced in weight by about 21% to 25% compared to the existing aluminum or FRP hull. It was also confirmed that this light-weight effect can induce the improvement of the maximum speed and the improvement of the operating range via simulations.

• Composites Research
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• v.36 no.1
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• pp.48-52
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• 2023

Fiber-reinforced composites have anisotropic material properties, so the mechanical properties of composite structures can vary depending on the stacking sequence. Therefore, it is essential to design the proper stacking sequence of composite structures according to the functional requirements. However, depending on the manufacturing condition or the shape of the structure, there are many cases where the designed stacking angle is out of range, which can affect structural performance. Accordingly, it is important to analyze the stacking angle in order to confirm that the composite structure is correctly fabricated as designed. In this study, the stacking angle was predicted from real cross-sectional images of fiber-reinforced composites using convolutional neural network (CNN)-based deep learning. Carbon fiber-reinforced composite specimens with several stacking angles were fabricated and their cross-sections were photographed on a micro-scale using an optical microscope. The training was performed for a CNN-based deep learning model using the cross-sectional image data of the composite specimens. As a result, the stacking angle can be predicted from the actual cross-sectional image of the fiber-reinforced composite with high accuracy.

• Composites Research
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• v.27 no.3
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• pp.109-114
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• 2014

Manufacture of nancomposites has simple process for developing nanocomposites due to the increasing applications using nanofillers. This work studied nanofiller coated glass fiber for reinforcing material with good wetting and conductivity and the morphology of nanofiller coated glass fiber was analyzed by FE-SEM. The durability of reinforced glass fiber was investigated with different shapes of nanofillers using sonication rinsing method. Fatigue test was performed to evaluate the adhesion of reinforcing interface and stability of nanofiller coating layer for single fiber reinforced composites. Apparent modulus and conductivity of nanofiller coating layer were evaluated to realize multifunctional of nanocomposites. Fiber type of nanofiller was better than plate type due to better cohesion between fiber and nanofillers. At last, the stability of fiber type nanofiller of coating layer has better durability and conductivity than plate type case.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.554-557
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• 2005

The bipolar plate is a major component of the PEM fuel cell stack, which takes a large portion of stack cost. In this study, as alternative materials for bipolar plate of PEM fuel cells, graphite composites were fabricated by compression molding. Graphite particles mixed with epoxy resin were used as the main substance to provide electric conductivity. To achieve desired electric properties, specimens made with different mixing ratio, processing pressure and temperature were tested. To increase mechanical strength, one or two layer of woven carbon fabric were added to the original graphite and resin composite. Thus, the composite material is consisted of the three phases: graphite particles, epoxy resin, and carbon fabric. By increasing mixing ratio, fabricated pressure and process temperature, electric conductivity was improved. The results of tensile test showed that the tensile strength of two-phase graphite composite was about 5MPa, and that of three-phase composite was increased to 54MPa.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.145-156
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• 2020

There are separate merits and demerits to wood and steel. The combination of wood and steel as a compound section is able to improve the properties of both and ultimately increase their final bearing capacity. The composite cross-section made of steel and wood has higher hardness while showing more ductility and the local buckling of steel is delayed or completely prevented. The purpose of this study is to investigate the behavior of composite columns enclosed in wooden logs and the hollow sections of steel that will be examined in a laboratory environment under the axial load to determine the final bearing capacity and sample deformation. In terms of methodology, steel sheet and carbon fiber reinforced polymer sheet (FRP) are tested to construct hollow rectangular sections and reinforce timber. Besides, the method of connecting hollow sections and timber including glue and screw has been also investigated. As a result, timber lumber enclosed with carbon fiber-reinforced polymer sheets in which fibers are horizontally located at 90° are more resistant with better ductility.