• 대한기계학회논문집A
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• 제26권3호
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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.

• 콘크리트학회논문집
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• 제19권6호
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• pp.735-744
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• 2007

본 연구는 CFRP 긴장재를 이용하여 외부 프리스트레싱으로 보강된 프리스트레스트 콘크리트 보에 관한 문헌 연구와 프리스트레싱 CFRP의 극한응력 예측식의 개발, 극한응력에 영향을 미치는 변수들에 대한 실험 등이다. 새로운 통합 예측식 개발을 위하여 비부착 프리스트레싱 CFRP의 극한응력에 대한 ACI 시방서 설계식을 확장하고 분석하였다. 본 논문에서는 외부 CFRP 긴장재의 극한응력에 대한 새로운 합리적 예측식을 제안하고 있는데, 프리스트레싱 긴장재와 중립축의 깊이비의 함수로서 표현하여 내부 PS 강재의 영향을 고려하고 있다. 실험 연구에서는 프리스트레싱 CFRP의 극한응력에 가장 큰 영향을 미치는 실험 변수를 가지고 외부 프리스트레싱으로 보강된 PSC 보를 제작하여 실험하였다. 실험 연구에서 채택한 영향인자들은 내부 PS 강재비, 외부 PS 긴장재비, 지간과 PS 강재 깊이비 등이다. 실험 결과는 분석되어 외부 프리스트레싱 CFRP의 극한응력에 대한 제안된 예측식의 합리성과 적용성을 확인하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제15권4호
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• pp.185-192
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• 2011

CFRP 보강공법은 구조물에 내하력을 증가시키기 위해 사용되고 있는데 실제 교량에 적합하고 연구 활용성이 좋다. 하지만, CFRP로 보강된 콘크리트 보에서 휨파괴와 전단파괴 뿐만 아니라 부착파괴 또한 추가적으로 발생하게 된다. 이러한 CFRP 부착파괴는 취성파괴를 유발하게 된다. 따라서 이러한 CFRP로 보강된 콘크리트보 박리에 대한 모니터링은 매우 중요한 의미를 갖는다. 본 논문에서는 국부적인 손상 파악에 유리한 PZT센서를 이용한 임피던스 기반 손상검색 방법을 사용하여 CFRP로 보강된 콘크리트보에서 박리 모니터링에 대한 적용가능성을 검증해 보았다.

• International Journal of Automotive Technology
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• 제6권5호
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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.

• 한국구조물진단유지관리공학회 논문집
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• 제14권5호
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• pp.72-78
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• 2010

CFRP보강공법은 구조물에 내하력을 증가시키기 위해 사용되고 있으며 실제 교량에 적용빈도가 높고 연구 활용성에 대한 기대가 큰 공법이다. CFRP로 보강된 콘크리트 구조물은 외부에 에폭시 등으로 접착된 CFRP로 인하여 휨파괴 및 전단파괴 외에 부착파괴가 추가적으로 발생하게 되며 이러한 부착파괴가 전체거동을 지배하게 되는 경우가 대부분이며, 취성파괴를 유발하게 된다. 따라서 이러한 CFRP 부착파괴에 대한 모니터링은 매우 중요한 의미를 갖는다. 본 논문에서는 국부적인 손상 파악에 유리한 PZT센서를 이용한 임피던스 기반 손상검색 방법을 사용하여 콘크리트 균열과 CFRP 부착파괴 모니터링에 대한 적용가능성을 검증해 보았다.

• 한국건축시공학회지
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• 제23권5호
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• pp.509-517
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• 2023

철근 부식을 해결하기 위해 FRP에 관한 연구가 증가하고 있다. CFRP는 경량화로 시공성이 용이하며, 내식성 및 내화학성이 뛰어나 이형철근 대체제로 지목되고 있다. 하지만 CFRP는 섬유와 레진을 압착하여 만들어져 열에 취약한 단점이 존재한다. 이러한 CFRP에 관한 연구는 미비한 실정이며, 본 연구에서는 고온 가열 이후 CFRP와 GFRP의 부착강도에 관한 연구를 실시하였다. 그 결과 규사코팅 CFRP와 리브형 CFRP, GFRP 모두 비슷한 부착강도 발현을 보였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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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.

• 대한기계학회논문집A
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• 제27권4호
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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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.

• 한국정밀공학회지
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• 제20권8호
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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.