• Title, Summary, Keyword: carbon fiber reinforced plastic

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Bonding Performance of Glulam Reinforced with Textile Type of Glass- and Aramid-Fiber, GFRP and CFRP

  • Kim, Keon-Ho;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.39 no.2
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    • pp.156-162
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    • 2011
  • To evaluate the bonding performance of reinforced glulam, the textile type of glass fiber and aramid fiber, and the sheet type of glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) were used as reinforcements. The reinforced glulam was manufactured by inserting reinforcement between the outmost and middle lamination of 5ply glulam. The types of adhesives used in this study were polyvinyl acetate resins (MPU500H, and MPU600H), polyurethane resin and resorcinol resin. The block shear strengths of the textile type in glass fiber reinforced glulam using MPU500H and resorcinol resin were higher than 7.1 N/$mm^2$, and these glulams passed the wood failure requirement of Korean standards (KS). In case of the sheet types, GFRP reinforced glulams using MPU500H, polyurethane resin and resorcinol resin, and CFRP reinforced glulams using MPU500H and polyurethane resin passed the requirement of KS. The textile type of glass fiber reinforced glulam using resorcinol resin after water and boiling water soaking passed the delamination requirement of KS. The only GFRP reinforced glulam using MPU500H after water soaking passed the delamination requirement of KS. We conclude that the bonding properties of adhesive according to reinforcements are one of the prime factors to determine the bonding performance of the reinforced glulam.

Flexural Strengthening Effect on R.C Beam with Structural Damage (구조적 손상을 입은 R.C보의 휨보강 효과)

  • Kim, Sung-Yong;Han, Duck-Jeon;Shin, Chang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.1
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    • pp.147-156
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    • 2004
  • The Rehabilitation and repair of structurally deteriorated, reinforced concrete structures will be highly demanded in the near future. The purpose of this study is to investigate whether damaged beams that crack and deflection are developed by bending moment are restored to the former state. In conclusion, when specimens strengthened with Steel Plate, CFS(Carbon Fiber Sheet) and CFRP-Grid(Carbon Fiber Reinforced Plastic-Grid) are compared with standard specimen, flexural capacity is increased and ductility and energy absorbtion capacity are similar with undamaged specimen. Therefore Steel Plate, CFS(Carbon Fiber Sheet) and CFRP-Grid (Carbon Fiber Reinforced Plastic-Grid) have highly efficiency as material of flexural strengthening.

Characteristics of Elastics Waves of Fiber-Reinforced Plastic with Localized Heat Damage (국부 열손상을 받은 복합재료의 탄성파특성)

  • 남기우;김영운
    • 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.

A Comparative Study on the Shear-Strengthening Effect of RC Beams Strengthened by FRP (FRP로 보강된 RC보의 전단보강효과 비교연구)

  • 심종성;김규선
    • Magazine of the Korea Concrete Institute
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    • v.10 no.4
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    • pp.101-111
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    • 1998
  • This study presents test results of RC beams strengthened by carbon fiber sheet(CFS), carbon fiber reinforced plastics(CFRP) or glass fiber reinforced plastics(GFRP) for increasing shear resistance. Nineteen specimens were tested, and the test was performed with different parameters including the type of strengthening materials(CFS, GFRP, CFRP), shear-strengthening methods(wing type, jacket type, strip type), strip-spacing, strengthening direction of FRP. The test results show that shear-damaged RC beams strengthened by FRP(CFS, GFRP, CFRP) have more improved the shear capacity. The mathematical model based on plastic theory was also developed to predict shear strength of shear-damaged RC beams strengthened by FRP. The predictions using the mathematical model. are agreed with the observations from the observed shear strengths for 19 test beams.

Application of AE for Fracture Behavior Evaluation of Carbon-fiber/SiC Reinforced Plastic Composites

  • Ryu, Yeong Rok;Kwon, Oh Heon
    • Composites Research
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    • v.30 no.5
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    • pp.267-272
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    • 2017
  • In this study, SiC powder was added to twill woven carbon fiber reinforced plastic (CFRP) composites to improve its mechanical properties. An acoustic emission (AE) frequency analysis method was suggested for the prediction of failure behaviors. Tensile tests were conducted and the fracture characteristics of each component of the SiC reinforced composite were evaluated using AE. The results showed that SiC powder improved the strength of twill woven CFRP composites and the fracture behavior of the SiC reinforced CFRP composite and its crack extension could be effectively evaluated on the basis of the specific AE frequency bands which are 100 to 228 kHz and 428 to 536 kHz upon the resin failure and 232 to 424 kHz due to addition of SiC powder and 576 to 864 kHz at the fiber breakage.

A Study on Mixed Mode I/II Interlaminar Fracture Toughness of Carbon Fiber Reinforced Plastic Composites (CFRP 복합재료의 혼합모드 I/II 층간파괴인성치에 관한 연구)

  • Kim, H.J.;Park, M.I.;Kim, J.D.;Koh, S.W.
    • Journal of Power System Engineering
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    • v.4 no.3
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    • pp.48-54
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    • 2000
  • This paper describes the effect of molding pressure, specimen geometries for Mixed Mode I/II interlaminar fracture toughness of carbon fiber reinforced plastic composites by using asymmetrical double cantilever beam(ADCB) specimen. The value of $G_{I/IIC}$ as a function of various molding pressure is almost same at 307, 431, 585 kPa. However it shows the highest value under 307 kPa molding pressure. The effect of $G_{I/IIC}$ due to the change of initial crack length of ADCB specimen was almost negligible in this study. It turns out that the condition for mix mode quasi-static crack growth in ADCB specimen is the ratio of the crack length to that of the specimen, i.e., ${\alpha}/L<0.4$.

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충격속도에 따른 GFRP 및 AFRP의 충격흡수에너지 거동

  • 김철웅;송삼홍;오동준
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.74-74
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    • 2004
  • 탄소섬유강화 적층재(Carbon Fiber Reinforced Plastic, 이하 CFRP)는 강성도는 뛰어나지만 충격특성에는 취약한 단점이 있다. 따라서 충격저항과 충격에너지 흡수율이 상대적으로 우수한 유리섬유강화 적층재(Glass Fiber Reinforced Plastic, GFRP) 및 아라미드섬유강화 적층재(Aramid Fbier Reinforced Plastic, 이하 AFRP)를 CFRP 적용분야에 대체하고 점차적으로 피로특성을 개선시켜 나간다면 특성이 더욱 개선된 제품을 사용할 수 있을 것으로 판단된다.(중략)

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Tribological Characteristics of Carbon Fiber Reinforced Plastics by Surface modification (탄소섬유복합재의 표면개질에 따른 트라이볼로지 특성에 관한 연구)

  • 전승흥;양준호;오성모;이봉구
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.29-36
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    • 2000
  • This investigation has been studied about friction and wear properties which were important problem, when carbon fiber reinforced plastic(CFRP) was used practically. Unidirection carbon fiber reinforced composites was fabricated with epoxy resin matrix and carbon fiber as a reinforced, and its surface was modified by the ion-assisted reaction. And then we tested the their friction and wear properties according to the ion-irradiation. when the amount of ion-irradiation was 1${\times}$10l6$\^$16/ ions/$\textrm{cm}^2$, the friction coefficient values were about 0.1, where as, the friction coefficient values of non-treatment composites were about 0.16. The former was the stablest in wear mode. We know that ion-irradiation was not proportioned to the friction coefficient, so we found the optimal conditions of the friction and wear according to the ion-irradiation.

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The Recovery of Carbon Fiber from Carbon Fiber Reinforced Epoxy Composites for Train Body (철도차량용 폐 복합소재에서의 탄소섬유 회수)

  • Lee, Suk-Ho;Lee, Cheul-Kyu;Kim, Yong-Ki;Kim, Jung-Seok;Ju, Chang-Sik
    • Proceedings of the KSR Conference
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    • pp.406-415
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    • 2008
  • Recently, the amount of thermosetting plastic wastes have increased with the production of reinforced plastic composites and causes serious environmental problems. The epoxy composites, one of the versatile thermosetting plastics with excellent properties, cannot be melted down and remolded as what is done in the thermoplastic industry. In this research, a series of experiments that recovers carbon fibers from carbon fiber reinforced epoxy composites for train body was performed. We experimentally examined various decomposition processes and compared their decomposition efficiencies and mechanical property of recovered carbon fibers. For the prevention of tangle of recovered carbon fibers, each composites specimen was fixed with a Teflon supporter and no mechanical mixing was applied. Decomposition products were analyzed by scanning electron microscope (SEM), gas chromatography mass spectrometer (GC-MS), and universal testing machine (UTM). Carbon fibers could be completely recovered from decomposition process using nitric acid aqueous solution, liquid-phase thermal cracking and pyrolysis. The tensile strength losses of the recovered carbon fibers were less than 4%.

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Influence of laminated orientation on the mechanical and thermal characteristics of carbon-fiber reinforced plastics

  • Shin, Hee-Jae;Kwac, Lee-Ku;Lee, Min-Sang;Kim, Hong-Gun
    • Carbon letters
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    • v.16 no.4
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    • pp.241-246
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    • 2015
  • Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, −15°/+15°, −30°/+30°, −45°/+45°, and −90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.