• Journal of the KSME
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• v.35 no.8
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• pp.709-715
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• 1995

날로 그 중요성이 대두되고 있는 환경보존 문제에 능동적으로 대응하고 여러 계층 소비자의 안 전도, 쾌적성 등에 관련된 요구, 성능의 수준향상에 효과적으로 대처하기 위해서는 차량의 경량화 기술이 가장 먼저 선행되어야 할 과제이다. 경량화를 추구하는 방법은 최적설계 개념을 이용한 구조합리화에 의한 방법과 알루미늄, 강화 플라스틱 등 신소재 대체에 의한 방법이 병행 연구 되고 있다. 이 글에서는 구조합리화를 통한 경량화 목표를 달성하기 위해 설계 초기 단계에 활용 가능한 단순 보 모델 개발의 필요성에 관해 언급하고 실차의 도어 측면 붕괴강도(door side intrusion strength), 루프 붕괴강도 (roof crush strength) 해석을 위한 단순 보 모델 개발에 관해 소개하고자 한다.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.67-69
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• 2003

콘크리트는 경제성과 압축강도, 내구성 및 강성 등의 우수한 물성을 가지고 있으나 인장, 휨 및 충격강도가 낮고 에너지 흡수능력이 작아 취성적이며 균열에 대한 저항성이 작은 단점을 가지고 있다. 이러한 단점을 개선하기 위해서 각종 섬유를 콘크리트에 분산시켜 만든 섬유보강시멘트(FRC : Fiber Reinforced Cement)의 개발 및 이용이 활발히 진행되고 있다. PVA 섬유는 우수한 선형성, 입체구조의 간략함과 규칙성, 고결정성 그리고 우수한 접착성을 가지며, 유기 고분자로는 유일하게 PH 13.5이상의 격렬한 알칼리 조건에서도 거의 손상되지 않는 우수한 내알칼리성을 가지고 있다. (중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.369-374
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• 2002

2002년 7월 1일부터 시행되는 제조물 책임법은 기업에 많은 영향을 끼칠 것으로 예상된다. 대외적으로는 소비자들의 클레임이나 분쟁, 혹은 소송에 대한 대응이 불가피할 것이며, 대내적으로는 제조공정의 품질 및 문서관리의 강화 요구에 대응하지 않으면 안될 것이다. 결과적으로 결함이 있는 제품의 출하 및 판매는 자칫 기업의 존폐 자체를 위협할 수 있기 때문에, 기업은 제품의 안전성을 평가하는 데 배전의 노력을 기울이고 있다.(중략)

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.361-370
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• 2005

Fiber reinforced composite (FRC) has been widely used in operative and prosthetic fields of dentistry and its use is expanding into the orthodontic field. The purpose of this study was to examine the changes of flexural properties of FRC reinforced with silica glass fiber (FibreKor, Jeneric/Pentron Inc.. Wallingford. U.S.A.) according to the duration of water absorption. Specimens were grouped according to their shape as round and rectangular cross sections, and were immersed in distilled water at room temperature $(23^{\circ}C)$ for 0 hour 1 hour 1 week. 15 days, 1 mouth and 3 mouths. The number of specimens was 5 for each duration and bending test was done using a torque tester The flexural stiffness after 24 hour water immersion was reduced to 59% for round specimens and 25% for rectangular specimens and after 3 mouths of water immersion it was reduced to 29% and 19% stiffness of the 0 hour-specimen respectively Yield flexural moment after 24 hour water immersion was reduced to 45%for round specimens and 76% for rectangular specimens and after 3 months of water immersion it was reduced to 29% and 60% stiffness of the 0 hour-specimen respectively Ultimate flexural moment after 24 hour water immersion was reduced to 35% for round specimens and 76% for rectangular specimens and after 3 mouths of water immersion it was reduced to 25% and 37% stiffness of 0 hour-specimen respectively. Those results suggested that the flexural stiffness of FibreKor decreased greatly after initial water immersion. Consequently, further research for the maintenance of strength against water will be necessary

• Composites Research
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• v.17 no.6
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• pp.1-7
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• 2004

The studies of particulate reinforced composites have been conducted for many years. The nanocomposites to be studied vigorously in recent years are one of them. We fabricated and studied multi-walled carbon nanotube(MWNT)/epoxy composites which may be useful as matrix for continuous fiber-reinforced composites. We investigated tensile properties of MWNT/epoxy composites as a function of MWNT concentration, which were prepared by the fabrication method established in this study. Tensile stiffness and strength increased 19% at 0.5 wt% and 12% at 0.2 wt%, respectively. We observed the reaggregation phenomenon of MWNTS during curing, which should be controlled to obtain higher tensile properties.

• Composites Research
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• v.30 no.6
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• pp.399-405
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• 2017

We manufactured the long fiber-reinforced thermoplastic prototype of under cover using in-line compounding technology, and investigated the formability, mechanical properties and durability of the prototype of under cover. We manufactured the injection mold for the prototype through injection molding analysis and consideration of weight reduction. We investigated the formability of the prototype by evaluating the residual length and dispersion of fiber, and also tested the mechanical properties such as flexural strength, stiffness and impact strength. We investigated the durability of the prototype by the Key-Life Test(KLT) method which is generally used for the automotive interior parts.

• Membrane Journal
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• v.25 no.2
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• pp.171-179
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• 2015

Perfluorinated sulfonic acid ionomers (PFSAs) have been widely as solid electrolyte materials for polymer electrolyte membrane fuel cells, since they exhibit excellent chemical durability under their harsh application conditions as well as good proton conductivity. Even PFSA materials, however, suffer from physical failures associated with repeated membrane swelling and deswelling, resulting in fairly reduced electrochemical lifetime. In this study, pore-filling membranes are prepared by impregnating a Nafion ionomer into the pore of a porous PTFE support film and their fundamental characteristics are evaluated. The developed pore-filling membranes exhibit extremely high proton conductivity of about $0.5S\;cm^{-1}@90^{\circ}C$ in liquid water.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.784-790
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• 2003

Present investigation shows the analysis results for ceramic reinforced metal matrix composite under uniaxial transverse tensile loading. The resulting deformation, the projected damage type, and stress-strain behavior were computed depending on microstructure details such as the type of periodic reinforcement array, and the type of interface bonding. A two-dimensional finite element analysis was conducted based on the unit-cell of square, hexagonal, or diagonal periodic away For composite with strong interface bonding, the transverse stress vs. strain curve was generally increased with the increase of the ceramic volume fraction. For the composite with weakly bonded interface, however, the transverse stress vs. strain curve was reduced against the ceramic volume fraction. The decrease was caused by the interface debonding-induced stiffness reduction of the composite. For the composite of weakly bonded interface, the relative reduction rate in the final limit stress for hexagonal array was larger than that for square array. Outcome of the present study was compared favorably with the published literature data.

• Journal of the Korean Institute of Gas
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• v.14 no.5
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• pp.7-12
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• 2010

This paper presents FE analysis on the stress and displacement behavior safeties of dome roof structures for a LNG outer tank, which is constructed by sets of H beams and reinforced concrete. The excitation force of 0.2g is applied at the center of the bottom concrete structure of an outer tank. The computed FEM results indicated that the maximum von Mises stress was shown at the edge of dome roof structure and the maximum displacement was produced at the center of dome roof. The results showed that the concentrated stress and displacement were steadily increased for an increased number of H beams. This means that the number of H beams does not critically affect to the safety of the dome roof structure because the stiffness of a reinforced concrete structure is much higher than that of H beams. Thus, the number of H beams may be restricted under 60 due to a dead weight of H beams for 0.2g excitation force.

• Journal of the Korea Concrete Institute
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• v.26 no.5
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• pp.581-589
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• 2014

This paper presents the tension stiffening behavior from experimental results of each 6 amorphous steel fibers and normal steel fibers reinforced direct tensile specimens with the main variables such as cover thickness to bar diameter ratio. A tension stiffening effect for steel fiber reinforced RC tension members improve on the increase in cover thickness, and also amorphous steel fiber is usually superior to normal steel fiber. The reinforcement of steel fibers controlled the splitting cracks and led to significant increase in the tension stiffening effect. In particular, if cover thickness is more than twice the bar diameter, the amorphous steel fiber reinforced specimen is controlled the splitting crack and increased the tension stiffening effect. And, the tension stiffening effect of amorphous steel fiber reinforced concrete tension members is different to current structural design code provision.