• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.63.2-63
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• 2003

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.17-18
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• 2006

• Proceedings of the Korean Fiber Society Conference
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• 2000.04a
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• pp.109-112
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• 2000

• Proceedings of the Korean Fiber Society Conference
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• 2000.04a
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• pp.343-346
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• 2000

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.2
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• pp.20-28
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• 2010

In this paper, new type CFFT (Concrete Filled FRP Tube) was suggested in order to improve the flexural stiffness. Since the existing CFFT was produced by filament winding process, re-bar for concrete may be necessary in order to ensure structural safety under flexure re-bar. In comparison with existing type CFFT, new type CFFT was reinforced by circular shaped pultrusion FRP without re-bar. Filament winding FRP was attached to the outer layer of pultrusion FRP. Structural behavior of new type CFFT filled with concrete (HCFFT) was investigated by the mechanical property test for the component element and the FE analysis. Furthermore, compressive strength of the HCFFT member based on the equation suggested in previous studies.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.94-101
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• 2017

Tow Prepreg is the intermediate material for filament winding process that has been "pre-impregnated fiber tow" with resin system. As "dry filament winding" process emerges as a reliable alternative to conventional filament winding (called "wet filament winding") process, interest in tow prepreg as a material for dry filament winding is rising as well. In this article, we have reviewed the recent research trends in carbon fiber tow prepreg for high-performance rocket motor cases, fuel tanks for hydrogen vehicles and other high-quality commercial pressure vessels.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.283.2-283.2
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• 2014

열필라멘트 화학증착공정(Hot Wire Chemical Vapor Deposition)에서 기상 에서 생성되는 하전된 실리콘 나노입자와 저온결정성 실리콘박막 증착의 연관성을 압력의 변화에 따른 상호비교를 통해 조사하였다. 필라멘트 온도는 $1800^{\circ}C$로 고정시키고 0.3~2 torr의 범위에서 공정 압력을 변화시키면서 증착하였다. 압력이 증가함에 따라 증착된 실리콘 박막의 결정화도는 증가하였으며, 증착속도는 감소하였다. 반응기 압력에 따른 기상에서 생성되는 나노입자의 크기분포의 변화를 조사하기 위하여 탄소막이 코팅된 투과전자현미경(Transmission Electron Microscopy) 그리드 위에 실리콘 나노입자를 포획하고 관찰하였다. 포획된 실리콘 나노입자의 크기분포와 개수농도는 압력이 증가함에 따라 감소하였다. 투과전자현미경을 이용하여 분석한 결과, 나노입자는 결정성 구조를 보였다. 압력이 증가함에 따라 나노입자의 크기가 감소하고 개수농도가 감소하는 것은 증착속도의 감소와 관련됨을 알 수 있다. 한편, 공정압력 증가에 따른 나노입자의 크기분포 및 개수농도 감소와 증착속도의 감소는 일반적으로 알려진 기상에서 석출하는 고상의 평형석출량(equilibrium amount of precipitation)이 압력의 증가함에 따라 증가한다는 사실과 일치하지 않는다. 이러한 압력경향성은 Si-H 시스템이 0.3~2 torr의 압력 영역에서 retrograde solubility를 갖는 것을 의미한다. 나노입자의 하전여부, 크기분포 및 개수농도를 측정하기 위하여 입자빔질량분석장비(Particle Beam Mass Spectroscopy)를 이용하였다. 그 결과, 실리콘 나노입자는 양 또는 음의 극성을 가진 하전된 상태임을 확인하였고, 투과전자현미경(TEM) grid에 포획한 실리콘 나노입자의 크기와 경향성이 일치하였다. 이는 나노입자가 저온의 기판에서 핵생성되어 성장하여 생성된 것이 아니라 열필라멘트 주위의 고온영역에서 생성된 것을 의미한다.

• Composites Research
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• v.14 no.2
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• pp.8-12
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• 2001

Filament Winding Process is a comparatively simple operation in which continuous reinforcements in the form of roving are wound over a rotating mandrel. It is well established and versatile method for storage tanks and pipes for the chemical and other industries. In this study, tensile strength of a filament wound ring specimens were evaluated by a split disk test fixture and a dress disk test fixture. The results obtained from experiments were compared with the theoretical values from the rule of mixtures. The purpose of this paper is the suggestion of an appropriate test method for the evaluation of tensile properties of filament wound structures. The tensile strength of a ring specimen tested by the dress disk test showed better agreement with the theoretical values than those tested by the split disk test because of higher stress concentration in edges of a split disk test fixture. The results showed that the tensile strength of a ring specimen was influenced by the geometry of test fixture, the continuity of fibers, fiber-tension, fiber-end and stress concentration in specimen.

• Composites Research
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• v.17 no.5
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• pp.1-6
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• 2004

Composite pressure vessels with HDPE (high density polyethlyne) liner with metal boss at each end were developed by Filament Winding Process. The vessel is composed of a dome-shaped part at each end and a cylinder-shaped part at the middle of the vessel. The environmental tests carried out for possible vessel materials such as High Density Polyethlyn (HDPE), resins and reinforcing fibers up to a year showed no significant damages. The boss was designed to minimize the gas leak which was verified by FEM analysis. Most ideal fiber tension was obtained by experimental method and the fiber volume fraction, $\textrm{V}_{f}$, obtained by image analyzer were 55.4 % in cylinder and 55.6 % in dome parts, respectively. Winding pattern is programmed to control the composite thickness in the dome areas such that the failure of the vessel may occur in the cylinder. During the cure, the vessel was rotated and a constant internal pressure of 0.62 bar was applied. From this, the vessel's burst pressure is improved by 28 %. The burst and fatigue tests for under-wound and fully wound vessel showed satisfactory results.

• Composites Research
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• v.23 no.6
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• pp.61-66
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• 2010

In this paper, the variation of mechanical properties of T800 carbon/epoxy composites according to the forming pressure, which was referred to previous studies on a filament winding process, were investigated. The specimens of all the tests were fabricated by an autoclave de-gassing molding process controlling forming pressure (absolute pressures of 0.1MPa, 0.3MPa, 0.7MPa including vacuum) and water jet cutting after fabricating composite laminates. Various tensile tests were performed for in-plane properties and interlaminar properties were also measured by using Iosipescu test jig. Fiber volume fraction was measured to correlate the property variation and the forming pressure. This properties are expected to be utilized in the design of Type III pressure vessel for hydrogen vehicles which uses the same carbon fiber (T800 carbon fiber) for the filament winding process.