• Composites Research
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• v.18 no.3
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• pp.1-6
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• 2005

Carbon nanofiber exhibits superior and of ien unique characteristics of mechanical, electrical, chemical and thermal properties. Despite of the excellent properties of carbon nanofiber, the properties of carbon nanofiber filled polymer composites were not increased largely. The reason is that it is still difficult to ensure the uniform dispersion of carbon nanofiber in a polymer matrix. In this study, for improvement of the mechanical properties of composites, carbon nanofiber reinforced hybrid composites was investigated. For the dispersion of carbon nanofiber. solution blending method using ultrasonic was used. Dispersion of carbon nanoifiber was observed by scanning electron microscope (SEH). Mechanical properties were measured by universal testing machine(UTM).

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.204-206
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• 2008

본 연구는 양모 복합섬유용 복합가공제 및 이를 이용한 양모 복합섬유의 복합가공방법에 관한 것으로서, 여러 실험조건을 통해 양모를 포함하는 다종 섬유간에 손상 또는 침해가 없으면서 색상의 균염성을 확보하고, 우수한 항균성, 발수성, 방오성을 발현할 수 있는 양모 복합섬유가공에 관한 연구이다.

• Composites Research
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• v.36 no.1
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• pp.32-36
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• 2023

Recently, as global environmental issues for sustainable development, such as carbon neutrality, have emerged, disposal methods of glass fiber composites, a material of existing wind turbines, have become a problem. To solve this problem, in this study, 30kW wind turbine blades were manufactured using flax fiber-based composites, which are eco-friendly natural fiber composites that can replace existing glass fiber composites, and their suitability was evaluated. First, mechanical strength tests were conducted to verify the feasibility of using eco-friendly natural flax fiber composites as a wind turbine blade material, and as a result, better strength were confirmed compared to previous studies on the properties of flax fiber composites. In addition, the suitability was confirmed through a static strength performance evaluation test to measure the static strength of the flax fiber composite blade using the manufactured 30kW class flax fiber composite blade.

• Composites Research
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• v.12 no.2
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• pp.10-25
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• 1999

A new evaluation method for the interfacial properties of fibrous composites based on a fragmentation technique is proposed by using the gradual multi-fiber composite, in which the inter-fiber spacing is gradually changed. The results showed that as the inter-fiber distance increased, the aspect ratio of broken fibers decreased while the interfacial shear strength between the fiber and matrix increased. When the reciprocal of the inter-fiber destance was taken for the above relations, both the aspect ratio and interfacial shear strength showed a saturated value. This means that the gradual multi-fiber composite indicates an upper bound in aspect ratio and an upper bound in interfacial shear strength. It was concluded that this fragmentation test could be a new method for composite evaluation, since reducing a difference between these two bounds is effective for composite strengthening. In addition an elastoplastic finite element analysis was carried out to relate the above results with fiber stress a distribution around fiber breaks. It was proved that the bound obtained in the gradual multi-fiber composite test is closely related to stress concentrations caused by a group of multi-fiber breaks.

• Composites Research
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• v.22 no.4
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• pp.41-49
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• 2009

Natural fiber reinforced composites are emerging as low-cost, lightweight, recyclable, and eco-friendly materials. These are biodegradable and non-abrasive. Due to eco-friendly and biodegradable characteristics of natural fibers, they are being considered as potential candidates to replace the conventional fibers. The chemical, mechanical, and physical properties of natural fibers have distinct features depending upon the cellulose content of the fibers which varies from fiber to fiber. The mechanical properties of composites are influenced mainly by the adhesion between matrix and fibers. Several chemical and physical modification methods of fiber surface were incorporated to improve the tiber-matrix adhesion resulting in the enhancement of mechanical properties of the composites. This paper outlines the works reported on natural tiber reinforced composites with special reference to the type of fibers, polymer matrix, processing techniques, treatment of fibers, and fiber-matrix interface.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.422-425
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• 1998

섬유강화 복합재료는 고성능 섬유와 고분자 수지를 조합하여 재료의 물성 향상 및 고기능화를 목적으로 만들어지는 재료이며, 사용되는 고분자 매트릭스의 종류에 따라 열가소성 복합재료와 열경화성 복합재료로 나뉘어진다. 이 중 열경화성 복합재료에 관한 연구 및 그의 실용화는 오래 전부터 활발히 진행되어 산업재료 및 군사, 우주용 재료로 각광을 받아 왔으나 최근 지구 환경문제가 심각해지면서 사용 후 분해 및 재활용이 가능한 열가소성 복합재료에 관한 연구에 관심을 가지게 되었다. (중략)

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.461-469
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• 2011

In this study, the effect of polyvinyl alcohol (PVA) fiber volume fraction on the pullout behavior of structural synthetic fiber in hybrid structural synthetic fiber and PVA fiber cement composites are presented. Pullout behavior of the hybrid fiber cement composites and structural synthetic fiber were determined by dog-bone bond tests. Test results found that the addition of PVA fiber can effectively enhance the structural synthetic fiber cement based composites pullout behavior, especially in fiber interface toughness. Pullout test results of the structural synthetic fiber showed the interface toughness between structural synthetic fiber and PVA fiber reinforced cement composites increases with the volume fraction of PVA fiber. The microstructural observation confirms the incorporation of PVA fiber can effectively enhance the interface toughness mechanism of structural synthetic fiber and PVA fiber reinforced cement composites.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1989.06b
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• pp.29-34
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• 1989

고분자 복합재료들은 오늘날 광범위하게 마찰 부위들에 응용되고 있다. 다양한 첨가제와 보강재들이 고분자 물질들에 넣어져 강도와 마모 특성들을 향상 시키고 있다. 예를 들어, 다양한 복합재료들로서 현재 입수 가능한 것에 베어링 재료들이 있으며 이에 포함되는 것이 자체 윤활 보강 플라스틱 들이며 이들에는 고체 윤활제, 즉, 테플톤, $MoS_2$, 혹은 흑연가루들이 첨가된다. 실험적 그리고 이론적인 연구들이 여러 조건들에서의 섬유 보강 복합 재료들의 마모 거동에 대하여 보고되었다(예를 들어, 미끄럼 마모, 연마 마모, 입자 충격 마모, 비빔 마모). Tsukizoe와 Ohmae의 보고에 의하면 탄성계수 탄소섬유 복합재료는 가장 적은 마모가 횡단 방향(Transverse)에서 있고, 고 강도 탄소 섬유 복합재료는 길이 방향(Longitudinal)에서 있다. 가장 많은 마모는, 고 탄성계수 복합재료는 길이 방향에서, 고 강도 섬유 복합재료는 횡단 방향에서 잇다. 그들이 또한 발표한 것은 양쪽의 고 탄성계수와 고 강도 섬유 복합재료들의 수직방향(Norma)에서 눌러 불음(Seizure)가 일어났다고 한다.

• Proceedings of the Korean Fiber Society Conference
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• 1996.10a
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• pp.205-208
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• 1996

• Composites Research
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• v.16 no.6
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• pp.1-9
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• 2003

In this paper, probabilistic failure analysis based on Weibull distribution function is proposed to predict the fiber strength of composite pressure vessel. And, experimental tests were performed using fiber strand specimens, unidirectional laminate specimens and composite pressure vessels to confirm the volumetric size effect on the fiber strength. As an analytical method, the Weibull weakest link model and the sequential multi-step failure model are considered and mutually compared. The volumetric size effect shows the clearly observed tendency towards fiber strength degradation with increasing stressed volume. Good agreement of fiber strength distribution was shown between test data and predicted results for unidirectional laminate and hoop ply in pressure vessel. The site effect on fiber strength depends on material and processing factors, the reduction of fiber strength due to the stressed volume shows different values according to the variation of material and processing conditions.