• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.941-946
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• 2018

Currently, due to the development of technology, the industry is proceeding with the development of advanced materials with high performance such as light weight, heat resistance and electric conductivity. Carbon Fiber Reinforced Plastics (CFRP) is an excellent material with high heat resistance, high strength and thermal shock resistance. In order to obtain excellent hole shape in CFRP drilling, we compared the modified drill shape and the conventional carbide drill. On the other hand, we determine the proper helix angle by observing the CFRP surface according to the helix angle at the trimming of the end mill proceeding after the hole machining.

• Composites Research
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• v.23 no.6
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• pp.1-6
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• 2010

The electrical conductivity of carbon-fiber reinforced plastics (CFRP's) has been improved by indium-tin oxide (ITO) nano-particle coating on carbon fibers for the purpose of lightning strike protection of composite fuselage skins. ITO nano-particles were coated on the surface of carbon fibers by spraying the colloidal suspension with 10~40% ITO content. The electrical conductivity of the CFRP has been increased more than three times after ITO coating, comparable to or higher than that of B-787 composite fuselage skins with metal wire-meshes on the outer surface, without sacrificing the tensile property due to the existence of nano-particles at fiber-matrix interface. The damage area by the simulated lightning strike was also verified for different materials and conditions by using ultrasonic C-scan image. As the electrical conductivity of 40% nano-ITO coated sample surpass that of the B-787 sample, the damage area by lightning strike also appeared comparable to that of the materials currently employed for composite fuselage construction.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.264-270
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• 2020

Design was developed through user-oriented service design methodology and survey was conducted on material selection criteria for prototype production to select CFRP (Carbon Fiber Reinforced Plastics) CNT (Carbon Nano Tube), which was applied to animal X-ray detector panel to design product and develop prototype. Completed prototype with the application of CFRP CNT panel was tested in drop test, frontal external pressure test, and dustproof/waterproof performance to confirm that it can be utilized as a portable animal X-ray detector used in outdoor environment.

• Journal of the Korea Institute of Building Construction
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• v.23 no.5
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• pp.509-517
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• 2023

The surge in FRP(Fiber Reinforced Plastic) research signifies the industry's pursuit to counteract the longstanding issue of rebar corrosion. Notably, Carbon Fiber Reinforced Plastic(CFRP) emerges as a commendable alternative, given its superior resistance to both corrosion and chemical interactions, thus positing itself as a potential replacement for traditional steel rebars. However, the layered composition of fibers and resin in CFRP flags a notable susceptibility to elevated temperatures. Despite its promise, comprehensive studies elucidating the full spectrum of CFRP properties remain ongoing. In this investigative study, we meticulously assessed the bond strength of CFRP post-exposure to high thermal conditions. Our findings underscored a parity in bond strength amongst silica sand-coated CFRP, rib-type CFRP, and Glass Fiber Reinforced Plastic(GFRP).

• Composites Research
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• v.23 no.1
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• pp.31-36
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• 2010

The improvement of electrical conductivity of carbon-fiber reinforced plastics (CFRP) has been investigated by silver nano-particles coating for the purpose of lightning strike protection. Silver nano-particles in colloid were sprayed on the surface of carbon fibers, which were then impregnated by epoxy resin to form a CFRP specimen. Electrical resistance was measured by contact resistance meter which utilize the principles of the AC 4-terminal method. Electrical resistance value was then converted to electrical conductivity. The coated silver nano-particles on the carbon fibers were verified by SEM and EDS. The electrical conductivity was increased by three times of the ordinary CFRP.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.122-128
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• 2001

The objective of the present study was to investigate the characteristics of the friction and wear according to the amount of ion-irradiation for the carbon fiber reinforced plastic(CFRP). Unidirectional carbon fiber reinforced composites were fabricated with epoxy resin as a matrix and carbon fiber as a reinforcement, and its surface was modified by the ion-assisted reaction. When the amount of ion-irradiation was $1{\times}10^{16}$ ions/$cm^2$, the friction coefficients of composites were about 0.1 and the wear mode was stable, whereas, the friction coefficient of non-treatment composites were about 0.16 and the wear mode was very unstable. But if the amount of ion-irradiation was $5{\times}10^{16}$ ions/$cm^2$, the friction coefficients were higher rather than that of $1{\times}10^{16}$ ions/$cm^2$. Consequently, the amount of ion-irradiation was not in proportion to the friction coefficients, and it was conformed that the optimal conditions would exist between broth of them.

• Tribology and Lubricants
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• v.18 no.1
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• pp.61-67
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• 2002

The objective of the present study was to investigate the characteristics of the friction and wear according to the amount of ion-irradiation for the carbon fiber reinforced plastic (CFRP). Unidirectional carbon fiber reinforced composites were fabricated with epoxy resin as a matrix and carbon fiber as a reinforcement, and its surface was modified by the ion-assisted reaction. When the amount of ion-irradiation was $1{\times}10^{16}$ $ions/cm^{2}$. the friction coefficients of composites were about 0.1 and the wear mode was stable. whereas, the friction coefficient of non-treatment composites were about 0.16 and the wear mode was very unstable. But if the amount of ion-irradiation was $5{\times}10^{16}$ $ions/cm^{2}$, the friction coefficients were higher rather than that of $1{\times}10^{16}$ $ions/cm^{2}$ Consequently. the amount of ion-irradiation was not in proportion to the friction coefficients, and it was conformed that the optimal conditions would exist between both of them.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.697-702
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• 1997

This study presents test results of RC beams strengthened by carbon fiber sheet (CFS) or carbon fiber reinforced plastics (CFRP) for increasing shear resistance. Fifteen specimens were tested, and the test was performed with different parameters including the type of strengthening materials (CFS, CFRP), shear-strengthening methods (wing type, jacket type, strip type), strip-spacing, strengthening direction of FRP. The results show that shear-damaged RC beams strengthened by either CFS or CFRP have more improved the shear capacity.

• Advanced Composite Materials
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• v.18 no.1
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• pp.77-93
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• 2009

This paper investigated the damage transition mechanism between the fiber-breaking mode and the fiber-avoiding crack mode when the fiber-length is reduced in the unidirectional discontinuous carbon fiber-reinforced-plastics (CFRP) composites. The critical fiber-length for the transition is a key parameter for the manufacturing of flexible and high-strength CFRP composites with thermoset resin, because below this limit, we cannot take full advantage of the superior strength properties of fibers. For this discussion, we presented a numerical model for the microscopic damage and fracture of unidirectional discontinuous fiber-reinforced plastics. The model addressed the microscopic damage generated in these composites; the matrix crack with continuum damage mechanics model and the fiber breakage with the Weibull model for fiber strengths. With this numerical model, the damage transition behavior was discussed when the fiber length was varied. The comparison revealed that the length of discontinuous fibers in composites influences the formation and growth of the cluster of fiber-end damage, which causes the damage mode transition. Since the composite strength is significantly reduced below the critical fiber-length for the transition to fiber-avoiding crack mode, we should understand the damage mode transition appropriately with the analysis on the cluster growth of fiber-end damage.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.4
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• pp.241-253
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• 2020

The Small-Unit Riverine Craft (SURC) is a small high-speed vessel used by navies and marine corps in relatively shallow waterway environments, such as riverine areas or littoral coasts. In the past, SURCs have primarily been rigid-hulled inflatable boats constructed using composite materials such as glass fiber reinforced plastics. More recently, single-hull SURCs have been manufactured using aluminum for weight reduction. In this study, a Carbon Fiber Reinforced Polymer (CFRP) material was applied instead to examine its feasibility in the basic design of an SURC with a hull length of 10 m. The CFRP structural design was obtained using the properties of a marine CFRP laminate, determined in a previous study. Next, the designed CFRP SURC was modeled to confirm its functionality, then compared with existing aluminum SURCs, indicating that the CFRP SURC was 41.49 % lighter, reduced fuel consumption by 30 %, and could sail 50 NM further for every hour of engine operation. A method for reducing the high cost of carbon fiber was also proposed based on the adjustment of the carbon fiber content to provide the optimum strength where required. The data developed in this study can be used as a basis for further design of CFRP craft.