• 대한조선학회논문집
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• 제40권1호
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• pp.55-62
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• 2003

This study has investigated physical and chemical properties of FRP waste, has manufactured polymer cement mortar using a crushed waste with sand and has evaluated its capability to develop the economical waste recycling technology. The study has investigated tension strength, hardness test and impact test as physical properties and also thermogravimetric characteristics and analyzed infrared spectroscope as chemical properties. Then the study has manufactured polymer cement mortar and has analyzed how the FRP waste fine aggregate replacement ratio has an effect on compression strength. Noticing admixture can complement strength drop occurred by the FRP waste fine aggregate replacement, the study examined an optimum rate of admixture addition and its reaction through electron microscope photos.

• Corrosion Science and Technology
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• 제9권1호
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• pp.48-55
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• 2010

The many vessels are built with FRP(Fiber-Reinforced Plastic) material for small boats and medium vessels. However, FRP is impossible to be used for recyclable material owing to environmental problems and causes large proportion of collision accidents because radar reflection wave is so weak that large vessels could not detect FRP ships during the sailing. Hence, Al alloy comes into the spotlight to solve these kinds of problems as a new-material for next generation instead of FRP. Al alloy ships are getting widely introduced for fish and leisure boats to save fuel consumption due to lightweight. In this study, it was selected 6061-T6 Al alloy which are mainly used for Al-ships and carried out various electrochemical experiment such as potential, anodic/cathodic polarization, Tafel analysis, potentiostatic experiment and surface morphologies observation after potentiostatic experiment for 1200 sec by using the SEM equipment to evaluate optimum corrosion protection potential in sea water. It is concluded that the optimum corrosion protection potential range is -1.4 V ~ -0.7 V(Ag/AgCl) for 6061-T6 Al alloy, in the case of application of ICCP(Impressed current cathodic protection), which was shown the lowest current density at the electrochemical experiment and good specimen surface morphologies after potentiostatic experiment for Al-Mg-Si(6061-T6) Al alloy in seawater environment.

• Structural Engineering and Mechanics
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• 제20권6호
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• pp.727-745
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• 2005

The present study is an experimental investigation into the behaviour of high strength concrete square short columns subjected to biaxial bending moments and strengthened by GFRP laminates. The main objectives of the study are: to evaluate the improvement in the structural performance of HSC short square columns subjected to small biaxial eccentricity when strengthened by externally applied FRP laminates, and to investigate the optimum arrangement and amount of FRP laminates to achieve potential enhancement in structural performance especially ductility. The parameters considered in this study are: number of FRP layers and arrangement of wraps. The load eccentricity is kept corresponding to e/t = 0.125 in two perpendicular directions to the columns principal axes, and the wraps are applied in single or double layers (partial or full wrapping). In the present work, test results of five full scale concrete columns are presented and discussed. The study has shown that FRP wraps can be used successfully to enhance the ductility of HSC columns subjected to biaxial bending by 300%.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.1009-1014
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• 2006

Synthetic materials with excellent thermodynamic characteristics and the merit of anti-corrosion are frequently used in buildings and constructions for enforcement of bent in stead of steel plates. Among them, many practical studies have been conducted on bond strength because of increased bond strength of FRP plates. Previous investigators identified the bond strength of FRP plates through experiments with settlement of various variables to identify the bond strength. However, the experiments to identify the bond force are difficult to be conducted because they requires large expenses and long time for equipment arrangement, thus, are conducted with limitation. In this study, for bond experiment, optimum neural network model was developed with use of Back-propagation and Conjugate gradient technique of previous investigators. Learning was performed with use of the variables of previous investigators in developed neural network model so as to identify the bond strength of FRP plates. for verification of developed model, credibility and excellence was proven by comparing with the models of previous investigators.

• Computers and Concrete
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• 제27권5호
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• pp.437-445
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• 2021

Retrofitting of structures has gained importance over the recent years. Particularly, Reinforced Cement Concrete (RCC) column strengthening has become a challenge to the structural engineers, owing to the risks and complexities involved in it. There are several methods of RCC column strengthening viz. RCC jacketing, steel jacketing and Fiber Reinforced Polymer (FRP) wrapping etc., FRP wrapping is the most promising alternative when compared to the others. The large research database shows FRP wrapping, through lateral confinement, improves the axial load carrying capacity of the columns under concentric loading. However, its confining efficiency reduces under eccentric loading. Hence a relative newer technique called Near Surface Mounting (NSM), in which Carbon FRP (CFRP) strips are epoxy grouted to the precut grooves in the cover concrete of the columns, has been thrust domain of research. NSM technique strengthens the column nominally under concentric load case while significantly under eccentric case. A novel configuration of NSM in which the vertical NSM (VNSM) strips are being connected by horizontal NSM (HNSM) strips was numerically investigated under both concentric and eccentric loading. It was found that the configuration with 6 HNSM strips performed better under eccentric loading than under concentric loading, while the configuration with 3 HNSM strips performed better under concentric loading than under eccentric loading. Hence an optimum of 4 HNSM strips is recommended as strengthening measure for the given column specifications. It was also found that Aluminum alloy cannot be used instead of CFRP in NSM applications owing to its lower mechanical properties.

• 한국구조물진단유지관리공학회 논문집
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• 제17권5호
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• pp.136-145
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• 2013

최근 발생한 대규모 지진으로 구조물의 내진보강에 대한 사회적 관심도가 높아지고 있다. 특히 내진 설계가 반영되지 않은 기둥은 취성적인 파괴로 구조물 전체붕괴를 유발하기 때문에 내진보강이 적용 되어야한다. 과거에는 단면증설법, 강판보강법등이 주로 적용되었고 최근에는 복합재료의 장점을 이용한 섬유보강법이 선호되고 있다. 그러나 이러한 보강법들은 구조물의 물리적 손상을 유발하며, 작업공간과 시간소비가 크다는 단점이 있다. 본 연구에서는 기존 보강법의 단점을 보강하여 복합재료 (Fiber reinforced polymer)와 Aluminum 체결부 이용한 FRP 내진보강재를 개발하였다. 비선형 유한요소 해석프로그램을 통해 개발된 FRP 내진보강재의 최적 보강량을 결정하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1181-1186
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• 2008

Insulators which are used in the domestic electrical industries are mostly depended on importation from some advance countries. Even though insulators which are made of ceramic material have been mostly used domestically, the ratio of usage on composite insulators is recently being increased because of difficulties in manufacturing and high cost regarding ceramic stuffs. In this research, we are trying to develop the composite insulators which are very efficient in insulation regardless of the matter of weight. Even though the technique of manufacturing composite insulator are quite generalized worldwide at the moment, one of the most important issue is to keep security on the know-how that an ingredient of insulated material named 'SF6 gas' is included. Therefore, The aim of this paper is to improve the bonding force and air tight property between two components of composite insulator, Flange and FRP Tube.

• 한국안전학회지
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• 제23권6호
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• pp.108-114
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• 2008

Although FRP is relatively new material for constructional use, there are several commercial GFRP bridge decks available today. In this paper we first set variables which decide the design of a GFRP deck based on commercial products. Under the assumption of linear elastic behavior under DB24 load, all the conditions of stability and serviceability are considered. We seek the best solution which minimizes the cross section area using genetic algorithm. The optimal solution shows that the shape is close to the ASSET deck with larger angle of the web and smaller area.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 춘계학술대회
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• pp.388-389
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• 2012

현재 해상풍력 발전 타워는 강구조로 제작되고 있으며, 발전용량의 증가에 따라 타워 구조체 또한 장대화 되는 추세이다. 강조조물의 특성상 좌굴에 취약하며, 장대화 됨에 따라 세장비가 증가하여, 좌굴 및 진동에 취약한 특성을 보이게 된다. 본 연구에서는 신형식 구조체인 이중관-콘크리트 합성 구조(DSCT; Double Skinned Composite Tubular)를 적용한 해상풍력 타워를 제시하고 요구 성능을 만족하는 최적 단면 설계를 제시하였다. 관은 섬유보강 합성수지 (FRP; Fiber Reinforce Polymer)와 강재를 적용한 경우를 고려하였으며, 모두 요구 성능을 만족하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.232-233
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• 2005

Stainless steel has been stably used closed by passivity oxidation films($Cr_2O_3$) is made by neutral atmospheric environment. However, passivity oxidation films of the surface of stainless steel occasionally comes to be destroyed in seawater which is influenced by an environment having halogen ion like $Cl^-$, then, localization corrosion comes to occur. Stainless steel 304 for shaft system material of the small-size FRP fishing boat on seawater environments made an experiment on simulation of sacrifical anode(Al, Zn). Through these experiment and study, following results have been obtained ; According to the field inspection and corrosion simulation, the corrosion on the 2nd class stainless steel shaft(STS 304) in FRP fishing boat has been verified to occur by crevice corrosion and galvanic corrosion etc.. According to the comparison and analysis of Stainless steel 304 shaft materials after simulation leaving unprotected and applying cathodic protection, unprotected shaft specimen of stainless steel 304 was severely corroded, but, protected shaft specimen was not totally corroded. This result is assumed to be made by the facts that anodic reaction, $Fe{\rightarrow}Fe^{2+}$ + $2e^-$, has been restricted by the cathodic protection current of sacrificial anode material.