• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.521-528
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• 2003

In this study, a newly modified soil nailing technology called as the NDB(New Down and Board) soil nailing system is introduced. To improve the trafficability, workability, and economical efficiency, SMC(Sheet Molding Compound) board is adopted instead of using the concrete block facing. The SMC board has a distinct advantage of showing a fine view by directly coating with any kind of environmental photos. Composite material properties of the SMC board and cement grout are distinguished features of the NDB soil nailing system. In the present study, both laboratory tests(bending and punching failure tests) and field pull-out tests are carried out to analyze the behavior characteristics of the NDB soil nailing system, including the stress and strain distribution.

• Tribology and Lubricants
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• 제18권5호
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• pp.345-350
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• 2002

Recently, as the development of manufacturing technique on SMC(sheet molding compound), various numerical and experimental approaches to injection and compression molding have been investigated. Injection and compression molding, however, has so various cases with complicated boundary condition that it is difficult to analyze mold characteristics precisely. In addition, since a slight change in process variables can significantly change the resulting mold thickness, a proper design is important to compression molding process. Therefore, in this study, the effects of various parameters on compression molding process have been investigated using FEM(finite element method) to formulate the melt front advancement during the mold filling process. To verify the results of present analysis, they are compared with those of reference. The results show a strong effect of initial charge volume, injection time and pressure as a result of variations in the rectangular charge shape.

• 한국생산제조학회지
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• 제21권5호
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• pp.830-835
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• 2012

A research for application of LDSMC(Low Density Sheet Molding Compound) composite is in progress for lightening the weight. This paper has performed fatigue test and simulation of external panel for Korean commercial vehicle. Before the fatigue test, static test was carried out. From the test, the structural safety was investigated using Goodman diagram. After the static test performance, the fatigue test was conducted at a range of load frequency 5Hz, a stress ratio(R) of 0.05 and an endurance limit of $10^6$ to obtain the S-N curve. The S-N curve is applied to the fatigue analysis of the external panel assembly. The result of FEM analysis was in accord with the experimental result within 83% confidence. It showed that the process to set up the safety range of allowable error is required in process of the design and simulation verification.

• 접착 및 계면
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• 제22권2호
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• pp.63-68
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• 2021

Unsaturated Polyester Resin (UPR)은 유리섬유와 같은 강화제와 함께 사용되어 복합재료로 사용된다. 열경화성 수지인 UPR은 복합재료의 다양한 성형법 중 생산성이 우수하고 대량생산에 유리한 sheet molding compound (SMC) 성형법으로 산업에서 사용되고 있다. UPR을 기지재로 하는 섬유강화복합재료는 가볍고, 물성이 뛰어난 장점이 있지만 충격에 약하여 깨지기 쉽고, 경화 이후에는 부피가 감소하는 단점이 있기 때문에 강인성과 유연성을 부여할 수 있는 폴리올과 캡핑제를 달리하는 폴리우레탄 4종을 합성하여 첨가하여 그 단점을 극복하고자 하였다.

• 한국지진공학회논문집
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• 제17권4호
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• pp.151-157
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• 2013

In this study, an externally reinforced structural system for SMC(Sheet Molding Compound) panel water tank, designed according to the Japanese design code, is experimented to evaluate its seismic performance. The test tank is 3m long, 2m wide and 3m high, considering the capacity and size of the shaking table. The measured hydrodynamic pressures are found to be approximately 70% of the Japanese design code values. It may be partially due to the convex shape effect of the unit panels. The analytical results of externally reinforced system based on the measured dynamic water pressures are found in good agreement with the test results. If the design hydrodynamic pressures are estimated properly, the proposed analytical model for the externally reinforced water tank becomes a useful design tool and the Japanese design code is found to provide a safe design for the external frames of SMC panel water tank.

• 복합신소재구조학회 논문집
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• 제5권1호
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• pp.1-8
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• 2014

Pultruded glass fiber reinforced polymeric plastic (PFRP) and FRP member manufactured by sheet molding compound (SMC) have superior mechanical and physical properties compared with those of conventional structural materials. Since FRP has an excellent corrosion-resistance and high specific strength and stiffness, the FRP material may be highly appreciated for the development of floating-type photovoltaic (PV) power generation system. In this paper, advanced floating PV generation system made of PFRP and SMC is designed. In the design, it includes tracking solar altitude by tilting photovoltaic arrays and tracking solar azimuth by spinning structures. Moreover, the results of the finite element analysis (FEA) are presented to confirm stability of entire structure under the external loads. Additionally, installation procedure and mooring systems in the Hap-Cheon Dam are discussed and the measurement of strain under the actual circumstances is conducted for assuring stability of actually installed structures. Finally, by comparison with allowable stress, appropriate safety of structure is confirmed to operate the system.

• 한국재료학회지
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• 제8권1호
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• pp.13-18
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• 1998

SMC(Sheet molding compound)욕조 생산시 발생하는 폐 FRP를 보강재로서 재활용하기 위하여 불포화 폴리에스테르 매트릭스 수지에 보강하고 보강재와 매트릭스 수지의 계면 결합력을 증진시키기 위하여 보강재를 실란계 커플링제[3-methylacryloxyviny1 silane (MAOS)]로 전 처리하여 복합재를 제조하고 기계적 물성 및 계면현사에 대하여 관찰하였다. 보강률이 20wt%인 복합재의 굴곡강도 및 굴곡탄성률이 각 각 110MPa, 8.0GPa로 가장 우수하였으며 커플링제(MAOS)의 노동가 0.50wt%인 복합재의 굴곡강도 및 굴곡탄성률은 약 10%정도 향상되어 각 각 120MPa, 9.2GPa을 나타내었다. 또한 주사전자현미경 관찰 결과 보강재를 커플링제(MAOS)로 처리한 복합재의 보강재와 매트릭스 수지는 물리, 화학적을 잘 결합하여 보강재와 매트릭스 수지의 계면에서 pull out현상이 확인되지 않았으며 크랙도 발생하지 않았다.

• 폴리머
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• 제24권4호
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• pp.564-570
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• 2000

욕조 생산시 발생하는 폐 FRP와 냉장고 등 가전품과 폐단열재로부터 발생하는 폐우레탄폼을 흡음 및 경량판재로 재활용하기 위하여 불포화 폴리에스테르 매트릭스 수지에 보강하여 복합재를 제조하였다. 또한 충진제의 함량의 변화가 복합재의 기계적 물성에 미치는 영향과 기지와 보강재간의 계면현상을 관찰하였다. 충진제의 함량이 70 wt%인 복합재의 인장강도는 82.34 MPa로 가장 우수하였으며, 인장탄성율은 보강재의 함량이 증가함에 따라 감소하였다. 또한 굴곡강도와 굴곡탄성율은 폐FRP의 함량이 70 wt%충진된 복합재가 가장 우수하였으며, 그 값은 각각 72.5, 958.4 MPa이었다. SEM 관찰 결과 70 wt% 충진된 충진제 매트릭스 수지의 계면에서 pull out 현상이 확인되지 않았으며 균열도 발생하지 않았고, 매트릭스 수지내에 충진된 폐 FRP/우레탄폼 충진제가 잘 분산되어 있음을 확인할 수 있었다.

• 한국환경과학회지
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• 제18권12호
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• pp.1339-1347
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• 2009

This study tried to investigate and analyze the actual state such as the regional, classified, and material characteristics of the water quality in order to research the several factors by which the filtrated water of the total 250 cases can be polluted in the water tank. The 215 points (86%) clean the water tanks twice a year regularly and J-city has done the best job of cleaning the water tanks. The fifty points (20%) of the total 250 investigation points examine the water quality of the water tanks every year, however, the 175 investigation points (70%) do not execute the inspection of water quality. In the case of the regional characteristics in the water quality, the 23 points (46%) in H-county, the 17 points (34%) in S-county, and the 16 points (32%) in G-city are incongruent in the standard, and the incongruity ratio of the water quality in J-city is the lowest. The result of the classified incongruity shows that total coliforms were found at the 61 investigation points, mesophilic bacteria were found at the 27 points, and turbidity was found at the 12 points. In the case of the material incongruity, concrete was found at the 63 investigation points as the most distinguished factor, and FRP (fiberglass reinforced plastic) at the 23 points, SMC (sheet molding compound) at the 12 points, and stainless steel was found at the 2 points.

• Composites Research
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• 제27권3호
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• pp.103-108
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• 2014

섬유강화복합재는 단위중량당 강도와 강성이 뛰어나고, 단위중량이 작으며, 내부식성이 뛰어난 점 등의 다양한 재료성질의 장점이 있는 재료로서 건설분야에 적용이 점차 증가하고 있으며, 섬유강화복합재의 건설분야에 활용한 예로 수상 부유식 태양광발전 구조물이 있다. 수상 부유식 태양광발전 구조물은 최근 저탄소 녹색성장의 대표적인 사례로 각광받고 있으며, 안전성 및 경제성을 확보하기 위한 연구가 다수 진행되었다. 또한 수상 부유식 태양광발전 구조물은 최근 국내에 상용화 단지가 시공되었다. 본 논문에서는 상용화 과정에서 경제성 및 시공성을 위해 개발된 수상 부유식 태양광발전 구조물의 요소기술의 연구 개발 내용을 제시하였다.