• Textile Coloration and Finishing
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• v.32 no.4
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• pp.245-254
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• 2020

The sheet molding compound composite has been applied divers section. This paper reports processing of carbon fiber reinforced thermosetting composite with diverse resins and which was composed of chopped carbon fiber (30 ~ 60 wt%). Normally the paste that the viscosity is over 15,000 cps has been used in traditional Sheet molding compound (SMC) machine. In this research, SMC machine was designed to make Carbon-sheet molding compound (C-SMC) prepreg which was composed with low viscosity resin (1,800 ~ 2,500 cps increase up to 10,000 cps after aging). In order to confirm the optimal processing condition. Mechanical strength tests including tensile test, shear test, impact test, flexural strength test were conducted on C-SMC composites. Plus we identified the correlation between the mechanical properties and prepreg processing condition (carbon ratio and applied resin).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.585-586
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• 2008

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.296-302
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• 2010

If the fiber reinforced plastic is exposed to the moisture for a long period of time, most of moisture absorption occurs on the resin place, thus dropping cohesiveness between the molecules as the water molecules permeated between high molecular chains grant high molecular mobility and flexibility. Also as the micro crack occurs due to the permeation of moisture on the interface of glass fiber and epoxy resin, it is developed to the overall damage of interface place. Hence, the study on absorption is essential as the mechanical and physical properties of fiber reinforced composites are reduced. However, the study on absorption has the inconvenience needing to expose composite materials to fresh water or seawater for 1 month or up to 1 year. Therefore, this study has exposed fiber reinforced composites to fresh water and has developed a model with an accuracy of 98% after comparing the analysis value obtained by using ANSYS while basing on the experimental value of property decline by absorption and the basic properties of glass fiber and epoxy resin used in the experiment.

• Magazine of the Korea Concrete Institute
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• v.4 no.1
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• pp.107-118
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• 1992

In order to examine the mechanical properties of carbon fiber reinforced cement composites with silica powder PAN - based carbon fiber and Pitch- based carbon fiber, and polymer impregnators experimental studies on CFRC impregnated in polymer were carried out. The effects of types, length, and content~i of carbon fibers and matrices of fresh and hardened CFRC impregnated in polymer were examined. The test results show that compressive, tensile, and flexural strength of CFRC impregnated in polymer were much more iriCreased than those of air cured and autodaved CFIIC CFRC impregnated in polymer was also considerably effective in improving toughness, freeze thaw resistance, loss of shrinkage, and creep resist ance, compared with air cured and autoclaved CFRC.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.455-461
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• 2018

This paper presents experimental investigations about flexural strength and durability of reinforced concrete beams repaired using ductile fiber reinforced cementitious composite (DFRCC) and carbon fiber sheet through freezing and thawing test. Total 14 RC beams of $100{\times}100{\times}400mm$ size were tested by 3-point bending and freezing and thawing test by KS F 2456. The beams were reinforced using 3D10 steels on both the tensile and compressive sides, and repaired on 3 sides expect on top cycle. Test results showed that the beams repaired using fiber carbon sheet revealed about 15% higher values of flexural strength compared than the cases of DFRCC motar. On the other hand, the results did not showed meaningful differences in the aspect of durability. For further research, consideration of the steel interference effect and real old specimens such as taken from real deteriorated structures are needed to be tested after repairing with DFRCC and carbon fiber sheet.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.529-536
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• 2020

This paper presents experimental investigations about compressive strength and durability of reinforced concrete compressive members repaired using ductile fiber reinforced cementitious composite (DFRCC) and carbon fiber sheet through freezing and thawing test. Total 24 RC specimens of 100x100x400mm size were tested by compressive strength test and freezing and thawing test by KS F 2456. The specimens were reinforced using 4D10 steels and repaired on 4 sides expect on top cycle. Test results showed that the specimens repaired using fiber carbon sheet revealed about 5% higher values of the compressive strength compared than the cases of DFRCC motar. On the other hand, the resurts did not showed meaningful differences in the aspect of durability. For further research, considerations of the steel interference effect and real old specimens such as taken from real deteriorated structures are needed to be tested after repairing with DFRCC and carbon fiber sheet.

• International Journal of Concrete Structures and Materials
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• v.5 no.1
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• pp.43-48
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• 2011

This paper presents the performance of anchor systems for reinforced concrete beams retrofitted with carbon fiber reinforced polymer (CFRP) strips. Nine simply-supported beams are tested with various anchor systems such as steel hooks, steel plates with anchor bolts, CFRP anchor plates, and near-surface mounted (NSM) CFRP strip. The effects of these anchors on the behavior of the retrofitted beams are discussed, including load-carrying capacity, failure modes, and ductility characteristics. Test results indicate that end-anchorage is an important parameter when a CFRP-retrofit design is conducted. Mechanical bolts and NSM CRFP anchors are recommended.

• Composites Research
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• v.34 no.2
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• pp.82-87
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• 2021

The mechanical properties of carbon fiber-reinforced epoxy composites (CFRPs) are greatly dependent on the interfacial adhesion between the carbon fibers and the epoxy matrix. Introducing nanomaterial reinforcements into the interface is an effective approach to enhance the interfacial adhesion of CFRPs. The main purpose of this work was to introduce graphitic nanofiber (GNFs) between an epoxy matrix and carbon fibers to enhance interfacial properties. The composites were reinforced with various concentrations of GNFs. For all of the fabricated composites, the optimum GNF content was found to be 0.6 wt%, which enhanced the interlaminar shear strength (ILSS) and fracture toughness (KIC) by 101.9% and 33.2%, respectively, compared with those of neat composites. In particular, we observed a direct linear relationship between ILSS and KIC through surface free energy. The related reinforcing mechanisms were also analyzed and the enhancements in mechanical properties are mainly attributed to the interfacial interlocking effect. Such an effort could accelerate the conversion of composites into high performance materials and provide fundamental understanding toward realizing the theoretical limits of interfacial adhesion and mechanical properties.

• Composites Research
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• v.33 no.3
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• pp.140-146
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• 2020

The purpose of this paper is to examine the possibility of weight reduction by changing the partition panel of vehicle from an existing aluminum material to carbon fiber reinforced plastics. Three weaving methods (plain, twill and satin) were used in the manufacture of composite materials, and they were produced and tested to derive their material properties. The analysis model of composite partition panel for torsional conditions was developed and the structural stability and system stiffness were evaluated according to Tsai-Hill failure criteria. With design variables for fiber orientation angles and stacking sequence, evolutional optimal algorithm was performed and as the results, the optimal composite partition panel was designed. In addition, the structural analysis results for strength and specific stiffness were compared with aluminum partition panels and composite partition panels to verify the possibility of weight reduction.

• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.1-6
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• 2018

The effects of the fiber direction, specimen size and temperature on the compressive strength of carbon fiber reinforced silicon carbide composite (C/SiC composite) manufactured by liquid silicon infiltration(LSI) is investigated. Tests were conducted in accordance with ASTM C 695 at room temperature and elevated temperatures. Experiments are conducted with two different specimens considering grain direction. With grain (W/G) specimens have a carbon fibers parallel to the load direction, but across grain (A/G) specimens have a perpendicular carbon fibers. To verify the specimen size effect of C/SiC composite, two types of specimens are manufactured. One has a one to two ratio of diameter to height and the other has a one to one ratio. The compressive strength of C/SiC composite increased as temperature rise. As specimens are larger, compressive strength of A/G specimens increased, however compressive strength of W/G decreased.