• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1439-1441
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• 2003

전기절연재의 구조재로 많이 사용되고 있는 FRP(fiber reinforced plastics)는 열경화성 수지를 접착성 결합제(binder)로 하고 고강도 섬유를 보강재로 한 복합재료로서 기계적, 화학적, 전기적 특성이 매우 우수하다. FRP의 기계적 강도는 유리섬유에 의존 하고 있으므로 유리섬유의 방향과 힘을 가하는 방향에 따라서 그 강도의 차이는 매우 크게 나타난다. 본 연구에서는 섬유의 배향에 따른 강도의 변화를 이해하기 위하여 시편을 제작하여 압축강도를 측정하고 압축강도와 응력의 분포를 유한요소법으로 시뮬레이션하였다. FRP rod에 압축응력이 가해졌을 때 섬유의 배향에 따른 파괴강도와 응력의 분포를 유한요소법을 이용하여 시뮬레이션하였고 모델링에는 3-D Shell과 3-D Brick 요소를 사용하였다. 제작된 시편의 강도특성과 시뮬레이션을 통한 응력의 분포를 서로 비교하여 시편의 파괴에 미치는 응력을 고찰하였다.

• 한국해양환경ㆍ에너지학회지
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• 제18권3호
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• pp.207-215
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• 2015

환경문제를 야기시켰던 해상용 FRP재활용에 대해 지난 10여 년간 다양한 국가적 지원이 이루어져서 폐FRP로부터 콘크리트 강화용 섬유 제작이 진행되어 왔다. 이렇게 제작된 강화 콘크리트에 대해 구조적 능력까지 시험한 바 있다. 시험 테스트 결과 재활용 FRP 가루를 사용한 콘크리트는 고강도 콘크리트의 압축강도를 감소시키지 않았을 뿐 만 아니라, 고강도 콘크리트의 내폭 특성을 상당히 증대시켰다. 그러나 폐FRP로부터 매트층의 분리 방법이 안정화되지 않았기 때문에 폐FRP 섬유 가루의 특성에 대한 연구는 종결되지 않았다. 본 연구는 폐FRP로부터 매트층을 분리하는 효과적이며 친환경적인 새로운 방법에 관한 것이며, 이것은 내폭성이 강한 제품이나 구조물에 적합한 FRP섬유가루 생산 공정에 유용한 재활용 공정이라 생각한다.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 2000년도 추계 학술논문발표회 논문집
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• pp.39-45
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• 2000

In recent years, composite materials such as fiber reinforced plastics (FRP) have gained considerable attention in the aircraft and automobile industries due to their light weight, high modulus and specific strength. In practice, control of chip formation appears to be the most serious problem since chip formation mechanism in composite machining has significant effects on the finished surface ［1,2,3,4,5］. Current study will discuss frequency analysis based on autoregressive (AR) time series model and process characterization in orthogonal cutting of a fiber-matrix composite materials. A sparsely distributed idealized model composite material, namely a glass reinforced polyester (GFRP) was used as workpiece. Analysis method employs a force sensor and the signals from the sensor are processed using AR time series model. The experimental correlation between the different chip formation mechanisms and model coefficients are established.(omitted)

• 복합신소재구조학회 논문집
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• 제5권4호
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• pp.52-57
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• 2014

Due to the advantageous mechanical properties of the fiber reinforced polymeric plastics(FRP), their application in the construction industries is ever increasing trend, as a substitute of structural steel which is highly vulnerable under hazardous environmental conditions (i.e., corrosion, humidity, etc.). In this study, hybrid FRP-concrete composite pile (HCFFT) connection is suggested. The HCFFT is consisted of pultruded FRP unit module, filament wound FRP which is in the outside of mandrel composed of circular shaped assembly of pultruded FRP unit modules, and concrete which is casted inside of the circular tube shaped hybrid FRP pile. Therefore, pultruded FRP can increase the flexural load carrying capacity, filament wound FRP and concrete filled inside can increase axial load carrying capacity. In the study, connection capacity of HCFFT(small and mid size) is investigated throughout experiments and finite element method. From the results of experiments, we suggested the connection methods about HCFFT pile connection.

• 한국해양공학회지
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• 제27권4호
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• pp.45-54
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• 2013

In this study, various types of composite materials and adhesives that are actually used in the shipbuilding field for small ships, leisure boats, and fishing boats were applied in the hand lay-up method and vacuum infusion method to manufacture specimens. Then the tensile strength, tensile modulus, flexural strength, and flexural modulus values of these specimens were obtained. In addition, the barcol hardness and fiber content were obtained from the specimens. The results showed that the strengths of the specimens manufactured using the vacuum infusion method were higher than those manufactured using the hand lay-up method. Moreover, the barcol hardness and fiber content were also higher in those manufactured using the vacuum infusion method. The specimens manufactured using the vacuum infusion method were thinner despite their large fiber content.

• 대한기계학회논문집A
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• 제27권3호
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• pp.440-449
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• 2003

Residual strength of fiber metal laminates after impact was studied. 3/4 lay up FML was fabricated using 4 ply prepreg, 2 ply aluminum sheets, and 1 ply steel sheet. Quasi isotropic ([0/45/90/-45]s) and orthotropic ([0/90/0/90]s) FRP were also fabricated to compare with FML. Impact test were conducted by using instrumented drop weight impact machine (Dynatup, Model 8250). Penetration load and absorbed energy of FML were superior to those of FRPs. Tensile tests were conducted to evaluate the residual strength after impact. Strength degradation of FML was less than that of FRP. This means that the damage tolerance of FML is excellent than that of FRP. Residual strength of each specimen was predicted by using Whitney and Nuismer(WN) Model. Impact damage area is assumed as a circular notch in WN model. Damage width is defined as the average of back face and top face damage width of each specimen. Average stress and point stress criterions were used to calculate the characteristic length. It is supposing that a characteristic length is a constant. The distribution of characteristic length shows that the assumption is reasonable. Prediction was well matched with experiment under both stress criterions.

• 한국CDE학회논문집
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• 제19권1호
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• pp.19-28
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• 2014

The filament winding method is widely used to manufacture products of fiber reinforced plastics (FRP), such as high pressure vessels, launch tubes and pipes. For reducing winding time, the method of winding by filament band which consists of several filament fibers is used. NC winding machine is used for precise winding and NC path is needed. Before filament winding, users should verify that winding path which presented by a line is appropriate by filament winding simulation. Also, the used length of each filament is different. So, if the peak filament exhausted, it causes to stop manufacturing. In this research, we developed software which visualizes 3D graphic of filament band winding path and simulates winding process on real time. And we proposed algorithm about calculation of each filament usage. We use geodesic equation for generating filament band surface and calculating the usage length of each filament.

• 한국해양공학회지
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• 제23권2호
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• pp.98-103
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• 2009

The resin infusion method is the latest technology of FRP laminating and cleaning to improve FRP hull quality. This method is focused on how to arrange infusion channels for the laminiating strategy. The laminating strategy using the resin infusion method has been utilized to complete the infusion work and remove the cavities on the FRP surface within the curing time. It is resulting from the arrangement of infusion and vacuum channels, the resin property, and the combination of FRP. This strategy has been depended on the field experience for manufacturing FRP without the resin infusion simulation. This study can help to improve the efficiency of FRP fabrication with the laminating strategy including the resin infusion simulation instead of the field experience.

• 한국해양공학회지
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• 제11권3호
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• pp.69-75
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• 1997

A A12024-T3 plate has been reinforced with AFRP to be a Hybrid-Composite, APAL. The fatigue life of the APAL has been investigated. The effects of bonding surface, numbers of AFRP bonded and AFRP orientation on fatigue life have been compared with A12024-T3 plate. Fatigue life of APAL has been remarkedly increased compared with that of A12024-T3 plate. The fatigue life has depended on bonding surface and AFRP orientation, but no relationship could be found with numbers of AFRP laminates.

• 한국해양환경ㆍ에너지학회지
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• 제11권1호
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• pp.50-54
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• 2008

지난 30여 년 동안 세계 각국에서는 FRP(fiber reinforced plastics)선박의 폐처리 또는 재활용(재자원화)을 위하여 실용성과 안정성을 지니는 많은 기계적 방법에 대한 연구 개발을 진행하여 왔다. 기술적, 사회경제적 관점에서 가장 선호되는 방법인 소위 '기계적 방법'에는 크게 파쇄와 분쇄를 거친 후 결과물을 재활용하는 방법과 단순 파쇄과정 대신 유리면포(roving cloth)의 박리파쇄와 분류과정을 통한 수지와 유리섬유의 개별적 재활용 방법이 있다. 그러나 추출되는 유리면포의 크기가 제한적이어서 결과물의 활용도는 크지 않았다. 기계적 재활용방법의 편리성에도 불구하고 또 다른 재활용방법연구는 열분해(가스화)와 소각연료화(고형에너지) 방안이다. 이는 재생에너지화를 목표로 하는 연구다. 많은 열분해연구가 진행되어 왔음에도 폐FRP의 재생에너지화의 가장 큰 걸림돌은 폐FRP내의 유리섬유분리의 어려움에 있다. 따라서 기계적 처리 방법으로 유리섬유를 효과적으로 추출 할 수 있다면 폐FRP 친환경적 재 자원화와 재생에너지화 연구는 크게 활성화 될 것이다. 본 논문에서는 기계적 방법에 있어 유리섬유의 효과적 분리추출과 열분해 방법에서 필요한 전처리 문제(수지함유량 증대)에 대한 적극적 해결 방안으로서 FRP의 복합재료특성을 응용한 친환경적 유리면포(로빙층) 분류 처리 방안을 개발하였다. 또한 본 유리면포에서 세단된 유리섬유는 기존 콘크리트의 물성강화용으로 직접 사용할 수 있을 것으로 사료된다.