• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.48-53
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• 2002

Fiber-reinforced composites are extensively used in electronic, ship and aerospace applications due to their high strength and high toughess. In these applications, they are often subjected to localized heat damage due to various sources. In order to ensure their reliability, it is important to predict their residual properties using nondestructive evaluation thchniques. Fabric fiber composite specimens were manufactured with six layers of the glass-fiber prepreg and the carbon-fiber prepreg, respectively. The specimens were subjected to a localized heat damage using a heated copper tip with a diameter of 10mm at 35$0^{\circ}C$(CFRP) and 30$0^{\circ}C$(GFRP), respectively. The specimens were then subjected to tension tests while acoustic emission (AE) activities of specimens were collected. The AE activity of all specimens showed three types of distinct frequency regions. Those are matrix cracking, failure of the fiber/matrix interface and fiber breakage.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.10a
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• pp.39-42
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• 2003

최근에 널리 쓰이고 있는 섬유강화 복합재료는 플라스틱 재료가 갖고 있는 가공성의 장점을 충분히 발휘한 재료로서 모재인 수지와 강화재인 강화섬유로 구성되며 사용된 섬유의 종류에 따라 유리섬유강화플라스틱(GFRP : glass fiber reinforced plastic)과 탄소섬유강화플라스틱(CFRP : carbon fiber reinforced plastic)으로 구분된다. 이 두 복합재료가 건설, 선박, 자동차 그리고 우주항공분야에 이르기까지 거의 모든 산업에서 다양하게 이용되고 있다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.809-810
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• 2012

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.11
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• pp.447-455
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• 2017

At the modern industry, the composite material has been widely used. Particularly, the material of carbon fiber reinforced plastic hardened with resin on the basis of fiber is excellent. As the specific strength and rigidity are also superior, it receives attention as the light material. Among these materials, the carbon fiber reinforced plastic using carbon fiber has the superior mechanical property different from another fiber. So, it is utilized in vehicle and airplane at which high strength and light weight are needed at the same time. In this paper, the tensile property due to the fiber design is investigated through the analysis study with CT specimen composed of carbon plastic reinforced plastic. At the stress analysis of CFRP composite material with hole, the fracture trend at the tensile environment is examined. Also, it is shown that the lowest stress value happens and the deformation energy of the pre-crack becomes lowest at the analysis model composed of the stacking angle of 60° through the result due to the stacking angle. On the basis of this study result, it is thought to apply the foundation data to anticipate the fracture configuration at the structure applied with the practical experiment.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.51-58
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• 2010

Recently, aerospace structures have lightweight trend in order to reduce the cost of fuel and system, Carbon Fiber Reinforced Plastic (CFRP) can give the ability to reduce weight at 20~50% as the substitution of metal alloy, and there are advantages such as high Non-rigid, specific strength and anti-corrosion, but it is difficult to prove its destruction properties due to heterogeneous structure and anisotropy. In this study we designed specimen, inducing distinguishing destructions of material (for example, matrix crack, fiber breakage, and delamination) by using the Carbon Fiber Reinforced Plastic (CFRP) which is used in a real aircraft, to apply acoustic emission technique to aerospace structures. And we gained data via tensile testing and acoustic emission technique, from which each fault signal was classified respectively by using AE parameters and waveform.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.206-206
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• 2017

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.42-47
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• 2009

Recently, the wide range of the composite materials is used for the making airplanes, trains and automobiles body for the lightweight. Despite having complex structures, composite materials usually have well defined mechanical characteristics. However, composite materials are difficult to understand the fracture mechanism clearly by simple mechanical test. Nondestructive evaluation (NDE) combined with mechanical testing can play a more important role and especially Acoustic Emission Testing (AET) would become known to be a useful tool to assess damage and fracture behavior of composites. In this study The experiment was performed to acquire the acoustic emission signal during tensile test using unidirectional CFRP specimen and the data was analyzed the acoustic emission parameters with the waveform.

• Prospectives of Industrial Chemistry
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• v.24 no.2
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• pp.31-37
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• 2021

일반적으로 cross-link된 열경화성 에폭시수지는 유기용매에 용해되지 않고 열에 용융되지 않는 특성이 있다. 따라서 에폭시수지가 사용된 물질, 특히 탄소섬유강화플라스틱(carbon fiber reinforced plastic, CFRP)은 재활용이 어렵고, 사용 후 폐기물 처리에 막대한 비용이 소비되고 있다. 본 원고는 열경화성 에폭시수지 응용물 중 CFRP의 재활용을 중심으로 한 친환경적 재활용 기술에 관하여 정리하였다. 특히, CFRP의 구성요소인 탄소섬유(CF)와 기지재인 에폭시수지를 모두 재활용 할 수 있는 화학적 방법에 관하여 보고한다. 더 나아가 열경화성 에폭시수지의 화학적 분해물의 재이용기술에 관한 예를 소개한다.

• Composites Research
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• v.34 no.5
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• pp.290-295
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• 2021

The application of lightweight structural composites to automobiles as a solution in line with global fuel economy regulations to curb global warming is recognized as a megatrend. This study was conducted to provide a technical approach that can respond to the issue of replacing parts that require conductive properties to maximize the application of thermoplastic carbon fiber reinforced plastics (CFRPs), which are advantageous in terms of repair, disposal and recycling. By utilizing the properties of the low-viscosity polymerizable oligomer matrix, it was possible to prepare a thermoplastic CFRP exhibiting excellent impregnation properties while uniformly mixing the conductive filler. Various carbon-based conductive fillers such as carbon black, carbon nanotubes, graphene nanoplatelets, graphite, and pitch-based carbon fibers were filled up to the maximum content, and electrical and thermal conductive properties of the fabricated composites were compared and studied. It was confirmed that the maximum incorporation of filler was the most important factor to control the conductive properties of the composites rather than the type or shape of the conductive carbon filler. Experimental results were observed in which it might be advantageous to apply a one-dimensional conductive carbon filler to improve electrical conductivity, whereas it might be advantageous to apply a two-dimensional conductive carbon filler to improve thermal conductivity. The results of this study can provide potential insight into the optimization of structural design for controlling the conductive properties of thermoplastic CFRPs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.218-218
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• 2003