• Title/Summary/Keyword: CFRP

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A Study on the CFRP Treatment by ion Assisted Reaction Method to Improve T-peel Strength of CFRP/Aluminum Composites (CFRP/알루미늄 복합재에서 이온도움반응법을 적용한 CFRP의 표면처리가 T-peel 강도에 미치는 영향에 대한 연구)

  • Lee, Gyeong-Yeop;Yang, Jun-Ho;Yun, Chang-Seon;Choe, Nak-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.3
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    • pp.570-575
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    • 2002
  • It is well-known that the bond strength between CFRP(Carbon Fiber Reinforced Plastic) and aluminum is significantly affected by the surface treatment of the CFRP and the aluminum. This study investigates the surface treatment of CFRP to improve the T-peel strength of CFRP/aluminum composites. The surface of %CFRP([0^0]_{14})$ was treated by the ion assisted reaction method under oxygen environment. T-peel strength tests were performed based on the procedure of ASTM D1876-95. The T-peel strength of surface-treated CFRP/aluminum composites was compared with that of untreated CFRP/aluminum composites. The results showed that the T-peel strength of surface-treated CFRP/aluminum composites was about 5.5 times higher than that of untreated CFRP/aluminum composites. SEM examination showed that the improvement of T-peel strength was attributed to the uniform spread and fracture of epoxy adhesive.

Ultimate Stress of Prestressing CFRP Tendons in PSC Beams Strengthened by External CFRP Prestressing (외부 CFRP 프리스트레싱으로 보강된 PSC 보에서 CFRP 텐던의 극한응력)

  • Park, Sang-Yeol;Kim, Chang-Hoon;Hong, Seong-Yong
    • Journal of the Korea Concrete Institute
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    • v.19 no.6
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    • pp.735-744
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    • 2007
  • This study deals with literature review, developing a predicting equation for the ultimate stress of prestressing (PS) CFRP, and experimental test with the parameters affecting the ultimate stress of prestressing CFRF in prestressed concrete beams strengthened by external prestressing. The ACI (American Concrete Institute) predicting equation for the ultimate stress of unbonded prestressing CFRP is analyzed to develop a new integrated predicting equation. The proposed predicting equation takes rationally the effect of internal PS steel into consideration as a function of prestressing tendon depth to neutral depth ratio. In the experimental study, prestressed concrete beams strengthened using external prestressing CFRP are tested with the test parameters having a large effect on the ultimate stress of prestressing CFRP. The test parameters includes infernal prestressing steel and external prestressing CFRP tendon reinforcement ratios, and span to depth ratio. The test results are analyzed to confirm the rationality and applicability of the proposed equation for predicting the ultimate stress of external prestressing CFRP.

Crack and Debonding Donitoring of RC Beams Strengthened with CFRP Plates (CFRP 판 보강 RC보의 균열 및 박리 손상 모니터링)

  • Yoon, Jun Ho;Han, Jung Hun;Cho, Doo Yong;Park, Sun Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.4
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    • pp.185-192
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    • 2011
  • A CFRP (Carbon Fiber-Reinforced Plastic) strengthening method being widely used to increase the load-carrying capacity of structures is very suitable for existing bridge structures. However, not only flexure and shear failures but also debonding failure might be additionally occured in reinforced concrete(RC) beams strengthened with the CFRP plates. The CFRP debonding failure would cause a brittle fracture of the beam. Therefore, health monitoring for the CFRP bonding condition is strongly required. In this study, a feasibility of the impedance-based damage detection method using PZT sensors was investigated through a series of experimental studies for realtime structural health monitoring(SHM) for the CFRP laminated concrete structures.

ENERGY ABSORPTION CHARACTERISTICS IN SQUARE OR CIRCULAR SHAPED ALUMINUM/CFRP COMPOUND TUBES UNDER AXIAL COMPRESSION

  • CHA C. S.;LEE K. S.;CHUNG J. O.;MIN H. K.;PYEON S. B.;YANG I. Y.
    • International Journal of Automotive Technology
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    • v.6 no.5
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    • pp.501-506
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    • 2005
  • With the respective collapse characteristics of aluminum and CFRP (Carbon Fiber Reinforced Plastics) tubes in mind, axial collapse tests were performed for aluminum/CFRP compound tubes, which are composed of square or circular shaped aluminum tubes wrapped with CFRP outside. In this study, the collapse modes and the energy absorption characteristics were analyzed for aluminum/CFRP compound tubes which have different fiber orientation angle of CFRP. Fracture modes in the aluminum/CFRP compound tubes were rather stable than those in the CFRP tubes alone, probably due to the ductile nature of the inner aluminum tubes. The absorbed energy per unit volume of the aluminum or the aluminum/CFRP compound tubes was higher than that of CFRP tubes. Meanwhile, the absorbed energy per unit mass, for the light-weight design aspect was higher in the aluminum/CFRP compound tubes than in the aluminum tubes or the CFRP tubes. The energy absorption turned out to be higher in circular tubes than in square tubes. Beside the collapse modes and the energy absorption characteristics were influenced by the orientation angle, and the compound tubes took the most effective energy absorption when the fiber orientation angle of CFRP was 90 degrees.

PZT Sensor-based Structural Health Monitoring for CFRP Laminated Concrete Structures (CFRP 보강 콘크리트 구조물의 PZT센서 기반 구조 건전성 모니터링)

  • Ryu, Sung-Chan;Kim, Ju-Won;Lee, Chang-Gil;Park, Seung-Hee;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.5
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    • pp.72-78
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    • 2010
  • A CFRP (Carbon Fiber-Reinforced Plastic) strengthening method is being very widely used to increase the load-carrying capacity of host structures, especially for bridges. However, not only flexure and shear failures but debonding failure also might occur in CFRP strengthened concrete structures. The CFRP debonding failure would cause a collapse accident of the host structure. Therefore, real-time health monitoring about the CFRP bonding condition is strongly required. In this study, a feasibility of the impedance-based damage detection method using PZT sensors is investigated through a series of experimental study monitoring both concrete cracks and CFRP debonding defects.

Post-Thermal Exposure Bond Strength Properties of CFRP and GFRP in Concrete (콘크리트 고온 가열 이후 CFRP와 GFRP의 부착강도 특성)

  • Kim, Ju-Sung;Jeong, Su-Mi;Kim, Young-Jin;Park, Sun-Gyu
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.5
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    • pp.509-517
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    • 2023
  • The surge in FRP(Fiber Reinforced Plastic) research signifies the industry's pursuit to counteract the longstanding issue of rebar corrosion. Notably, Carbon Fiber Reinforced Plastic(CFRP) emerges as a commendable alternative, given its superior resistance to both corrosion and chemical interactions, thus positing itself as a potential replacement for traditional steel rebars. However, the layered composition of fibers and resin in CFRP flags a notable susceptibility to elevated temperatures. Despite its promise, comprehensive studies elucidating the full spectrum of CFRP properties remain ongoing. In this investigative study, we meticulously assessed the bond strength of CFRP post-exposure to high thermal conditions. Our findings underscored a parity in bond strength amongst silica sand-coated CFRP, rib-type CFRP, and Glass Fiber Reinforced Plastic(GFRP).

Energy Absorption Characteristics of Al/CFRP Compound Tubes Under Axial Compression (축 하중을 받는 AI/CFRP 혼성튜브의 에너지흡수 특성)

  • 이길성;차천석;문지현;양인영
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.108-113
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    • 2004
  • The compressive axial collapse tests were performed to investigate energy absorption characteristics of Al/CFRP compound tubes which are aluminum tubes wrapped with CFRP (Carbon Fiber Reinforced Plastics) outside the aluminum circular and square tubes. Based on collapse characteristics of aluminum tubes and CFRP tubes respectively, the axial collapse tests were performed for Al/CFRP compound tubes which have different fiber orientation angles. Test results showed that Al/CFRP compound tubes supplemented the unstable brittle failure of CFRP tubes due to ductile nature of inner aluminum tubes. In the light-weight aspect, specific energy absorption were the highest for Al/CFRP, CFRP in the middle, and aluminum the lowest. Also, specific energy absorption of circular tubes was higher than square tubes'. It turned out that fiber orientation angle of Al/CFRP compound tubes influence specific energy absorption together with the collapse modes of the tubes.

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A Study on the Fracture Toughness Improvement of Surface-treated CFRP and Aluminum Composites (표면처리된 CFRP와 알루미늄 복합재료의 파괴인성 향상에 대한 연구)

  • Rhee, Kyong-Yop;Kim, Man-Tae;Choi, Nak-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.4
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    • pp.632-637
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    • 2003
  • In this study, the effect of surface treatment of CFRP and aluminum on the fracture toughness of CFRP/aluminum composites was investigated. CFRP was surface-treated by Ar$^{+}$ ion beam under oxygen environment, and the aluminum was surface-treated by DC plasma. CFRP was adhesively bonded to aluminum using the secondary bonding procedure. Cracked lap shear specimens were used to determine fracture toughness. Three cases of cracked lap shear specimens were made depending on the surface treatment. The values of fracture toughness of three cases were compared to each other It was found that the fracture toughness of ion beam-treated CFRP/aluminum composites was almost 72 % higher than that of unrented CFRP/aluminum composites. The fracture toughness of CFRP/plasma-treated aluminum composites was 50 % higher than that of untreated CFRP/aluminum composites.s.

Flexural Behavior of RC Beams Strengthened with CFRP Strips (탄소섬유판으로 보강된 RC보의 휨 거동)

  • Choi, Ki-Sun;You, Young-Chan;Park, Young-Hwan;Park, Jong-Sup;Kim, Keung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.287-290
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    • 2005
  • CFRP strips manufactured in factory are produced normally with smaller width and larger thickness than CFRP sheets. By this reason, bonding force between CFRP strips and concrete substrate is not sufficient to sustain tensile force in CFRP strips. Therefore premature debonding failure cannot be avoided when strengthening is done by simply bonding the CFRP strips. The flexural strength of RC beam strengthened with CFRP strips must be calculated based on the effective strain considering debonding failure. This paper presents test results of an experimental study conducted to evaluate the flexural strength on RC beams strengthened with CFRP strips. 7 specimens were tested with respect to bond length and amount of CFRP strips. From the test results, it was indicated that the strain of the CFRP strips achieved at debonding failure can be decreased less than 6,000$\mu$ depending on the amount of CFRP strips.

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Effect of Plasma Treatment of Aluminum on the Fracture Toughness of Aluminum/CFRP Composites (알루미늄의 플라즈마 표면처리가 알루미늄/CFRP 복합재의 파괴인성에 미치는 영향)

  • 신명근;이경엽
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.8
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    • pp.153-157
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    • 2003
  • In the present work, the effect of plasma treatment of aluminum on the fracture toughness of CFRP/aluminum composites was investigated. The surface of the aluminum was treated by a DC plasma. The plasma treatment was carried out at volume ratio of acetylene gas to nitrogen gas of 5:5 and the treatment time used was 30 sec. Cracked lap shear specimens of aluminum/CFRP composites were made using secondary bonding procedure. Fracture toughness of aluminum/CFRP composites was determined using the work factor approach. Then, the fracture toughness of plasma-treated aluminum/CFRP composites was compared with that of untreated aluminum/CFRP composites. The results showed that the fracture toughness of plasma-treated aluminum/CFRP composites was about 50 % higher than that of untreated aluminum/CFRP composites.