• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.723-736
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• 2014

Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties.

• 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.

• 한국해양공학회지
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• 제24권1호
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• pp.146-152
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• 2010

Recently, the applied frequency of composite materials was increased from the viewpoint of lightweight, high strength and low cost when a leisure boat and a fishing boatwere built. However, studies on the mechanical properties of composite material with ship are rare. Specially, a leisure boat and fishing boat with FRP had been built by hand lay-up method. However, the vacuum infusion method is rising recently for ship building. The manufactured these FRP plates were combined by using the adhesive. Therefore, in this study Cleavage peel strength, Shear strength and fatigue limit of adhesive bonds by tensileloading were estimated. From test results, the strengths of FRP specimens made by the vacuum infusion method are higher than that of the hand lay-up method.

• 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.

• 전기전자학회논문지
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• 제22권2호
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• pp.274-280
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• 2018

본 논문에서는 보트 안정성 및 품질 향상을 위해 배큠인퓨전(vacuum infusion) 자동화 기술을 개발한 다. 보트 생산시 매우 짧은 시간에 정확한 혼합비율로 수지와 경화제가 혼합되어 진공으로 선체와 데크 내부에 흡착되기 때문에 강도 변형 및 후(後) 변형성 등은 매우 중요하다. 배큠인퓨전 시스템을 이용하면 수지와 경화제의 혼합 비율 등의 조건을 정확하게 제어하고, 보트의 건조 및 강성 확보를 위한 최적 조건을 찾는 것이 가능하게 된다. 시간대별 수지 유동율 및 수지 흐름도 등은 작업 조건에 대한 모델별 정보 분석 및 최적화 정보를 DB화하여 내구성 등의 품질을 향상시킨다. 또한 다수 작업장에서 소수 작업 인원으로 효율적인 생산 공정 관리가 가능하여 생산비를 절감 한다.

• 한국해양공학회지
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• 제24권5호
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• pp.75-80
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• 2010

Fiberglass-Reinforced Plastic (FRP) composites have been used for small fishing boats and leisure boats for many years. These composites have different physical characteristics, depending on the constitution of lay-up and manufacturing method. Recently, new manufacturing methods, such as vacuum infusion, have been used to make the composites lighter and stronger. In this research, the mechanical properties of fiberglass reinforcements with constitution of lay-up, manufacturing method, and two different resins were investigated experimentally. It was found that the mechanical properties of FRP composites increased with increasing thickness, with the use of vacuum infusion method, and with the use of vinyl ester resin. The mechanical properties of diverse FRP composites can be used as a practical guide for selecting appropriate materials for specific applications.

• Carbon letters
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• 제25권
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• pp.43-49
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• 2018

This study suggests the novel thermoplastic toughening agent, which can be applied in the monomer forms without increasing the viscosity of the epoxy resin and polymerized during the resin curing. The diazide (p-BAB) and dialkyne (SPB) compounds are synthesized and mixed with the epoxy resin and the carbon fiber reinforced epoxy composites are prepared using vacuum infusion process (VIP). Then, flexural and drop weight tests are performed to evaluate the improvement in the toughness of the prepared composites to investigate the potential of the novel toughening agent. When 10 phr of p-BAB and SPB is added, the flexural properties are improved, maintaining the modulus as well as the toughness is improved. Even with a small amount of polytriazolesulfone polymerized, due to the filtering effect of the solid SPB by the layered carbon fabrics during the VIP, the toughening and strengthening effect were observed from the novel toughening agent, which could be added in monomer forms, p-BAB and SPB. This suggests that the novel toughening agent has a potential to be used for the composites prepared from viscosity sensitive process, such as resin transfer molding and VIP.

• 한국식품과학회지
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• 제28권2호
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• pp.393-395
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• 1996

배추조직의 연화방지를 위해 0.05 M $CaCI_2$ 용액중에서 배추의 예비열처리와 pectinesterase 주입전처리 및 효소의 침투를 용이하게 하기 위한 감압처리의 효과를 조사하였다. $CaCI_2$ 용액중 예비열처리에 의해 줄기는 약 50% 이상 경도가 증가하였고, 잎사귀의 경우는 약 4-5배 증가하였으며, PE 효소를 첨가한 경우 줄기 및 잎사귀 모두에서 경도가 더욱 증가하여 상승효과를 나타내었다. 배추를 감압처리한 후 효소를 주입 처리한 경우. 잎사귀 부분에서는 별다른 변화가 없었으나 줄기 부분의 경우 감압처리후 효소주입처리한 시료들은 모두 경도가 증가하였으며, 저장시험에 따르면 김치제조 4일째까시 경도유지 효과가 있었으나 그 후 점차 감하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권1호
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• pp.45-56
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• 2010

Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet) in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP) composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL), vacuum infusion (VI), and hybrid (HL+VI) processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented dining composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

• Composites Research
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• 제34권4호
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• pp.233-240
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• 2021

VaRI(Vacuum assisted Resin Infusion) 공정은 공정비용이 저렴하며, 크기가 큰 복합재 제작에 적합한 OoA(Out of Autoclave) 공정이다. VaRI 공정에서는 원할한 수지 주입을 위해 섬유 상단에 유로망을 적층한다. 수지는 이 유로망을 따라 섬유의 면 방향으로 빠르게 공급되고, 공급된 수지는 다시 섬유의 두께방향으로 함침된다. 면방향의 유동과 두께방향의 유동이 동시에 일어나기 때문에 수지의 유동을 예측하기 힘들며, 수지 주입과정을 예측하기 위해 3D 수치해석 프로그램이 사용되고 있다. 하지만, 3D로 해석하기 위해서 섬유와 유로망의 두께방향에 많은 Element가 필요하고, 이로 인해 제품의 크기가 클수록 해석시간이 오래 걸린다. 따라서 본 연구에서는 3D 유동해석을 2D 해석으로 간소화하여 유동해석에 소요되는 시간을 줄이는 방법을 제시하였다. 3D 유동해석과 간소화된 2D 유동해석을 동일조건에서 비교하여 효용성을 검증하였고, 충진시간 오차율은 약 7%, 유동해석시간 감소율은 약 95%로 나타났다. 또한 3D 해석에서 섬유 상, 중, 하단 간의 유동 전진 거리의 차이가 일정하다는 것을 활용하여 간소화된 2D 유동해석에서도 상, 중, 하단의 유동 전진 거리를 예측할 수 있었다.