• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.129-132
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• 2007

From this research the construction civil official is simple with the parking floor finishing material, it improves the durability of the parking floor it uses the flexible FRP it will be able to secure the drainage quality it is excellent and it presents the efficient application plan from the construction site. The performance appraisal only efficiency with of result floor of parking area material bay it knows, the result where also the performance appraisal portion re-with roof bottom finishing is satisfied it showed. The flexible FRP it applies the material to the building as to diminish the damage of the bottom finishing material due to the deterioration and the conduct and the external force of the building it is exposed to the external environment, secures the quality of the material from the construction site and will contribute to the stability against the bottom finishing material.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.34-39
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• 2002

A Semi-Autonomous Underwater Vehicle (SAUV) capable of simple work at sea bed is under development in KRISO-KORDI. A pressure vessel of SAUV which is composed of FRP was manufactured to load electronic equipments. The objective of this paper is to verify the safety of the pressure vessel through conducting the structural analysis and test in pressure tank. Strain and stress under unit load were obtained by using ANSYS in the linear structural analysis. And local buckling analysis was performed with NASTRAN for the middle cylindrical hull. For the pressure test, strains were measured at three point. We found that the results by linear structural analysis and experiment are coincide well at the points where buckling does not occur. Maximum depth was estimated to be 250m by the local buckling analysis.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.52-58
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• 2004

A Semi-Autonomous Underwater Vehicle (SAUV), capable of simple work on the seabed, is under development in KRISO-KORDI. This SAUV pressure vessel is composed of fiberglass reinforced plastic (FRP), and is also manufactured to carry electronic equipment. The objective of this paper is to describe the safety check for the pressure vessel. This is achieved fly conducting structural analysis and testing in a pressure tank. Strain and stress test results, under unit load, are obtained fly using ANSYS in linear structural analysis. Local buckling analysis are performed with NASTRAN at the middle oj the cylindrical hull. The first test, using linear structural analysis, is unsuccessful, as buckling occurred. During the second test, linear structural analysis, combined with local buckling analysis, is conducted. There is no buckling up to 250 m when both ANSYS and NASTRAN are used.

• Elastomers and Composites
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• v.46 no.3
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• pp.223-230
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• 2011

Considering of utilizing renewable resources and recycled plastics, green composites consisted of recycled polyethylene (PE) as matrix and eco-friendly natural fibers as reinforcement were processed and characterized in the present study. First, the wood flour/recycled polyethylene pellets with different wood flour contents were prepared by twin-screw extrusion processing. Using the pellets, wood flour/recycled polyethylene green composites were fabricated and the effects of wood flour loading on their flexural, tensile, impact properties, heat deflection temperature and fracture behavior were investigated. It was concluded that the flexural strength, flexural modulus, tensile modulus and heat deflection temperature of wood flour/recycled polyethylene green composites were increased with wood flour, whereas the tensile strength and impact strength were decreased. The fracture behavior observed by means of scanning electron microscopy supported qualitatively the tendency of the impact strength with wood flour loading, compared with the ductile fracture pattern of recycled polyethylene.

• Composites Research
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• v.28 no.6
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• pp.378-382
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• 2015

With increasing population density and high-rise expansion of buildings in recent years, elevators have become to play a pivotal role in our everyday lives as most people take an elevator several times even in a day. The elevator penetration and distribution rates in Korea have increased dramatically every year, and the emergence of skyscrapers leads to accelerating the development of elevator industry. Carbon-fiber-reinforced plastics (CFRPs) exhibit better mechanical and thermal properties than steel suitable for uses as elevator wire ropes. In this paper, in order to analyze the properties of CFRPs, the tensile strength of unidirectional (UD) CFRP wire ropes was characterized and finite element analysis was conducted for bending simulation. Simulation results were compared.

• Composites Research
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• v.35 no.6
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• pp.469-476
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• 2022

In this paper, the microwave absorbing characteristics after the impact of the radar-absorbing structure (RAS) consisting of periodic pattern sheet (PPS) and glass fiber-reinforced plastic (GFRP) were experimentally investigated. The fabricated RAS effectively absorbed the microwave in the X-band (8.2-12.4 GHz). In order to induce the damage to the RAS, a low-velocity impact test with various impact energy of 15, 40, and 60 J was conducted. Afterward, the impact damage was observed by using visual inspection, non-destructive test, and image processing method. Moreover, the absorbing performance of intact and damaged RAS was measured by the free-space measurement system. The experiment results revealed that the delamination damage from the impact energy of 15 J did not considerably affect the microwave absorbing performance of the RAS. However, fiber breakage and penetration damage with a relatively large damaged area were occuured when the impact energy was increased up to 40 J and 60 J, and these failures significantly degraded the microwave absorbing characteristics of the RAS.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.357-363
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• 2009

This study was carried out to investigate whether adhesive used in manufacturing glulam can be used to bond wood and GFRP, when considering working process and economical efficiency. The six different glulams were manufactured, changing the adhesives and the mixing ratios of the adhesives, and investigated by the block shear test and the delamination of the water soaking or boiling water soaking. The three glulams were manufactured, using the resocinol resin based adhesive, the PVAc resin based adhesive and the epoxy resin adhesive, and the other three glulams, using the adhesives mixing resocinol resin and PVAc resin. The block shear strength is higher than $7.1N/mm^2$ in all types, which is standard of KS F3021. However, in the wood failure the block shear strength was the highest as 65.9% in the PVAc. The delamination of glulams glued with PVAc adhesive, which was 1.08% in water soaking and 4.16% in boiling water soaking, was lower than 5.00% which is the standard of KS F 3021, and the adhesive strength is good. In glulams glued with only resocinol resin adhesive, the wood layers were good as 1.26% in the water soaking delamination and 0.00% in the boiling water soaking delamination. The GFRP layers were not good as 21.85% in the water soaking delamination but were good as 1.45% in the boiling water soaking delamination.

• Composites Research
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• v.28 no.4
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• pp.143-147
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• 2015

This paper proposes laser ultrasonic technique for the impact damage inspection of hydrogen fuel tank and proves that the impact damage can be visualized using an ultrasonic wave propagation imager with an easy detachable sensor head as an impact damage inspection tool for hydrogen fuel tanks. Also the performances of the proposed ultrasonic propagation imager support it can be implemented in real-world technology when the hydrogen car becomes popular.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.61-69
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• 2011

Fiber Reinforced Plastic (FRP) sheets have been widely used to retrofit and rehabilitate RC structures, while in case of retrofitting steel structures, there are no codes and researches. It stems from configuration of member and characteristics of bonding behavior. This study focused on the static behavior of steel beams reinforcement by AFRP sheets. The main objective of the experimental programme was the evaluation of the force transfer mechanism, the increment of the beam load carrying capacity and the bending stiffness. A bending test was conducted on a H-shaped steel beam, with aramid FRP sheets bonded to its flanges. The mid-span deflection and the strain from three points along AFRP sheets were recorded Test results exhibit that the increment of the load-carrying capacity with reference to a mid-span deflection level of 15 mm(1/125mm of the clear span) was equal to 9.4% and for the two layers case, an elastic stiffness increment is slightly higher than one layer case.

• Journal of Adhesion and Interface
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• v.13 no.2
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• pp.58-63
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• 2012

CFRP chip is the byproduct from carbon fiber reinforced plastic (CFRP) processing. CFRP chip is not simply a waste mainly composed of fine carbon fiber and epoxy resin. CFRP chip keeps matrix to maximize their reinforcing effect. To obtain a uniform length of carbon fiber in CFRP chip, chip was chopped ina mortar. CFRP chip should be purified to get better interface adhesion. Epoxy resin on the carbon fiber was removed by $H_2O_2$ surface etching treatment. Optimal dispersion and fabrication conditions of CFRP chip embedded in phenolic resin were determined by thermal stability for fire retardant applications. CFRP chip-phenolic composite exhibits better mechanical and thermal properties than neat phenolic resin. Surface condition of CFRP chip-phenolic composite was evaluated by static contact angle measurement. Contact angle of CFRP chip-phenolic composite was greater than neat phenolic due to heterogeneous condition of fine carbon fibers. From the evaluation for fire retardant (ASTM D635-06) test, thermal stability of CFRP chip-phenolic composite was found to be improved with higher concentration of CFRP chip.