• Title/Summary/Keyword: carbon fiber reinforced composite

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Detection of Delamination Crack for Polymer Matrix Composites with Carbon Fiber by Electric Potential Method

  • Shin, Soon-Gi
    • Korean Journal of Materials Research
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    • v.23 no.2
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    • pp.149-153
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    • 2013
  • Delamination crack detection is very important for improving the structural reliability of laminated composite structures. This requires real-time delamination detection technologies. For composite laminates that are reinforced with carbon fiber, an electrical potential method uses carbon fiber for reinforcements and sensors at the same time. The use of carbon fiber for sensors does not need to consider the strength reduction of smart structures induced by imbedding sensors into the structures. With carbon fiber reinforced (CF/) epoxy matrix composites, it had been proved that the delamination crack was detected experimentally. In the present study, therefore, similar experiments were conducted to prove the applicability of the method for delamination crack detection of CF/polyetherethereketone matrix composite laminates. Mode I and mode II delamination tests with artificial cracks were conducted, and three point bending tests without artificial cracks were conducted. This study experimentally proves the applicability of the method for detection of delamination cracks. CF/polyetherethereketone material has strong electric resistance anisotropy. For CF/polyetherethereketone matrix composites, a carbon fiber network is constructed, and the network is broken by propagation of delamination cracks. This causes a change in the electric resistance of CF/polyetherethereketone matrix composites. Using three point bending specimens, delamination cracks generated without artificial initial cracks is proved to be detectable using the electric potential method: This method successfully detected delamination cracks.

Effect of fiber-matrix adhesion on the fracture behavior of a carbon fiber reinforced thermoplastic-modified epoxy matrix

  • Carrillo-Escalante, H.J.;Alvarez-Castillo, A.;Valadez-Gonzalez, A.;Herrera-Franco, P. J.
    • Carbon letters
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    • v.19
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    • pp.47-56
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    • 2016
  • In this study, the fracture behavior of a thermoplastic-modified epoxy resin reinforced with continuous carbon fibers for two levels of fiber-matrix adhesion was performed. A carbon fiber with commercial sizing was used and also treated with a known silane, (3-glycidoxy propyl trimethoxysilane) coupling agent. Toughness was determined using the double cantilever test, together with surface analysis after failure using scanning electron microscope. The presence of polysulfone particles improved the fracture behavior of the composite, but fiber-matrix adhesion seemed to play a very important role in the performance of the composite material. There appeared to be a synergy between the matrix modifier and the fiber-matrix adhesion coupling agent.

Fabrication and Characterization of the Carbon Fiber Composite Sheets (탄소섬유를 이용한 열가소성 복합재료 시트 제조 및 특성)

  • Lee, Yun-Seon;Song, Seung-A;Kim, Wan Jin;Kim, Seong-Su;Jung, Yong-Sik
    • Composites Research
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    • v.28 no.4
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    • pp.168-175
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    • 2015
  • Recently, the applications of carbon fiber reinforced plastics (CFRPs) have become broader than ever when it comes to such industries as automotive, ships, aerospace and military because of their lightweight-ness and high mechanical properties. Thermosetting plastics like epoxy are frequently used as the binding matrix in CFRPs due to their high hardness, wetting characteristics and low viscosity. However, they cannot melted and remolded. For this reason, thermosetting plastic wastes have caused serious environmental problems with the production of fiber reinforced plastics. Thus, many studies have focused on the carbon fiber reinforced thermoplastics (CFRTPs) and recycling carbon fiber. In this study, recycled carbon fiber (RCF) was prepared from CFRPs using a pyrolysis method, which was employed to separate resin and carbon fiber. The degree of decomposition for epoxy resin was confirmed from thermal gravimetric analysis (TGA) and scanning electron microscope (SEM). The RCF was cut and ground to prepare a carbon fiber composite sheet (CFCS). CFCS was manufactured by applying recycled carbon fibers and various thermoplastic fibers. Various characterizations were performed, including morphological analyses of surface and cross-section, mechanical properties, and crystallization enthalpy of CFCS at different cooling conditions.

Fabrication and Mechanical Characterization of Braided Carbon Fiber Reinforced Al Matrix Composites (Braided 탄소섬유강화 알루미늄 기지 금속복합재료의 제조 및 기계적 특성평가)

  • 김경태;이상관;홍순형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2002.10a
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    • pp.131-134
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    • 2002
  • Braided carbon fiber reinforced Al matrix composites were developed and characterized. Braided carbon fiber preforms with braiding angles of $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$ were manufactured by using a braiding machine. The manufactured braided carbon fibers were used as reinforcement to fabricate Al matrix composites by employing a pressure infiltration casting method. In the processing of pressure infiltration casting, important processing parameters such as melting temperature, preheating temperature of preform and applied pressure were optimized. Prediction of elastic constants on composites was performed by using the volume averaging method, which utilizes the coordinate transformation and the averaging of stiffeness and compliance constants based upon the volume of each reinforcement and matrix material. The elastic moduli of composites were evaluated by using Resonant Ultrasound Spectroscopy(RUS) method and compared with the elastic moduli obtained from static tensile test method.

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Toughness Enhancement of Carbon Fiber Reinforced Composites for Automobile using Silica Fume (실리카 퓸을 이용한 자동차용 탄소섬유강화복합재의 인성 강화)

  • Lim, Sungmook;Yu, Jaesang;Lee, Wonoh
    • Journal of Institute of Convergence Technology
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    • v.8 no.1
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    • pp.27-31
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    • 2018
  • The age of electric vehicle is coming. One of the most important problems to be solved for popularization of electric vehicle is fuel economy. To increase fuel economy of electric vehicles, it is necessary to improve the performance of the battery or the car body should be lighter than now. To solve the problem of the car body, change the car body's material to carbon fiber reinforced composites can be an excellent answer. However, the part made from carbon fiber reinforced composites is vulnerable to accidents due to their high brittleness. In this study, ductile silica fume was added into the carbon fiber composites to enhance toughness. To examine this, various amounts and sizes of silica fume were considered and the toughness enhancement was examined by performing tensile tests.

Drop-weight impact damage evaluation for carbon fiber/epoxy composite laminates (탄소 섬유강화 복합재료의 중력 낙하 충격으로 인한 손상 평가)

  • Sohn, Min-Seok;Hu, Xiao-Xhi;Ki, Jang-Kyo;Hong, Soon-Hyung
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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    • pp.89-92
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    • 2001
  • Drop weight impact tests were performed to investigate the impact behavior of carbon fiber/epoxy composite laminates reinforced by short fibers and other interleaving materials. Characterization techniques, such as cross-sectional fractography and scanning acoustic microscopy, were employed quantitatively to assess the internal damage of some composite laminates. Scanning electron microscopy was used to observe impact damage and fracture modes on specimen fracture surfaces. The results show that composite laminates experience various types of fracture; delamination, intra-ply cracking, matrix cracking and fiber breakage depending on the interlayer materials. Among the composite laminates tested in this study, the composites reinforced by Zylon fibers showed very good impact damage resistance with medium level of damage, while the composites interleaved by poly(ethylene-co-acrylic acid) (PEEA) film is expected to deteriorate the bulk strength due to the reduction of fiber volume fraction, even though the damaged area is significantly reduced.

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Thermal Conductivity and Thermal Expansion Behavior of Pseudo-Unidirectional and 2-Directional Quasi-Carbon Fiber/Phenolic Composites

  • Cho, Donghwan;Choi, Yusong;Park, Jong Kyoo;Lee, Jinyong;Yoon, Byung Il;Lim, Yun Soo
    • Fibers and Polymers
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    • v.5 no.1
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    • pp.31-38
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    • 2004
  • In the present paper, a variety of fiber reinforcements, for instance, stabilized OXI-PAN fibers, quasi-carbon fibers, commercial carbon fibers, and their woven fabric forms, have been utilized to fabricate pseudo-unidirectional (pseudo-UD) and 2-directional (2D) phenolic matrix composites using a compression molding method. Prior to fabricating quasi-carbon fiber/phenolic (QC/P) composites, stabilized OXI-PAN fibers and fabrics were heat-treated under low temperature carbonization processes to prepare quasi-carbon fibers and fabrics. The thermal conductivity and thermal expansion/contraction behavior of QC/P composites have been investigated and compared with those of carbon fiber/phenolic (C/P) and stabilized fiber/phenolic composites. Also, the chemical compositions of the fibers used have been characterized. The results suggest that use of proper quasi-carbonization process may control effectively not only the chemical compositions of resulting quasi-carbon fibers but also the thermal conductivity and thermal expansion behavior of quasi-carbon fibers/phenolic composites in the intermediate range between stabilized PAN fiber- and carbon fiber-reinforced phenolic composites.

Electromagnetic Interference shielding effectiveness of carbon black / Glass fiber woven roving and Carbon fiber unidirectional fabric reinforced composite (카본블랙/섬유강화 복합재료의 전자파 차폐효과)

  • Kim J.S.;Han G.Y.;Ahn D.G.;Lee S.H.;Kim M.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1322-1325
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    • 2005
  • The main objectives of this research work are to develop conductive glass fiber woven roving and carbon fiber unidirectional fabric composite materials and to determine their electromagnetic shielding effectiveness(EMSE). Epoxy is the matrix phase and glass, carbon fiber are the reinforcement phase of the composite material. Carbon black are incorporated as conductive fillers to provide the electromagnetic shielding properties of the composite material. The amount of carbon black in the composite material is varied by changing the carbon black composition, woven roving and unidirectional (fabric) structure. The EMSE of various fabric composites is measured in the frequency range from 300MHz to 800MHz. The variations of EMSE of woven roving and unidirectional composites with fabric structure, metal powder composite are described. Suitability of conductive fabric composites for electromagnetic shielding applications is also discussed.

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Thermal Properties according to Content and Alignment of Carbon Fiber in Cu Matrix Composite Reinforced with Chopped Carbon Fiber (탄소 단섬유가 첨가된 Cu기지 복합재료의 섬유 분율 및 배열에 따른 열적 특성)

  • Kim, Minkyoung;Han, Jun Hyun
    • Korean Journal of Materials Research
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    • v.31 no.11
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    • pp.626-634
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    • 2021
  • Cu matrix composites reinforced with chopped carbon fiber (CF), which is cost effective and can be well dispersed, are fabricated using electroless plating and hot pressing, and the effects of content and alignment of CF on the thermal properties of CF/Cu composites are studied. Thermal conductivity of CF/Cu composite increases with CF content in the in-plane direction, but it decreases above 10% CF; this is due to reduction of thermal diffusivity related with phonon scattering by agglomeration of CF. The coefficient of thermal expansion decreases in the in-plane direction and increases in the through-plane direction as the CF content increases. This is because the coefficient of thermal expansion of the long axis of CF is smaller than that of the Cu matrix, and the coefficient of thermal expansion of its short axis is larger than that of the Cu matrix. The thermal conductivity is greatly influenced by the agglomeration of CF in the CF/Cu composite, whereas the coefficient of thermal expansion is more influenced by the alignment of CF than the aggregation of CF.

An Experimental Study on Mortar Beam Stengthened by Composite Material (모르타르 보의 복합재료 보강 효과에 관한 실험적 연구)

  • 차승환;정일섭
    • Composites Research
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    • v.13 no.3
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    • pp.1-8
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    • 2000
  • Excellent environmental durability and handy installation procedure as well as high specific strength and stiffness have introduced fiber-reinforced polymeric composite materials into the civil and architectural engineering field. This study presents the considerably enhanced strength characteristics of the mortal beams by being reinforced with epoxy-bonded carbon fiber sheets(CFS). Three point bending and Charpy impact tests were performed on both of bare and reinforced mortar specimens. The influences of length, and the number of reinforcing plies were investigated. Strength reduction due to pre-existent notch was lessened dramatically. The acoustic emission(AE) measurement revealed the progressive damage process in reinforced specimens.

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