국내 기후변화와 급격한 도시화가 진행함으로써 도심지 불투수 면적 증가로 인하여 자연적인 물순환이 원활히 이루어 지지 않고 있다. 이로 인해 국지성 폭우로 인한 지표수의 증가로 도심지 홍수 피해가 빈번하게 발생하고 있는 실정이다. 이에 본연구에서는 주차장 매립 빗물저류조를 통하여 지표 유출량을 감소시켜 원활한 물순환에 기여하고 그에 따른 해 당 구조물의 상부 하중과 배열 방식에 따른 거동 특성을 분석하고자 한다. 해당 구조물의 분석은 유한요소 해석을 이용 하였으며, 분석 결과 매립 깊이 3m 이상 시 상부 하중이 저류조에 적용되는 하중이 급격하게 저감되는 결과를 나타냈다.

AR (alkali resistant)-glass fibers were developed to provide better alkali resistance, but there is currently no research on AR-glass fiber manufacturing. In this study, we fabricated glass fiber from AR-glass using a continuous spinning process with 40 wt% refused coal ore. To confirm the melting properties of the marble glass, raw material was put into a (platinum) Pt crucible and melted at temperatures up to 1,650 °C for 2 h and then annealed. To confirm the transparent clear marble glass, visible transmittance was measured and the fiber spinning condition was investigated by high temperature viscosity measurement. A change in diameter was observed according to winding speed in the range of 100 to 700 rpm. We also checked the change in diameter as a function of fiberizing temperature in the range of 1,240 to 1,340 °C. As winding speed increased at constant temperature, fiber diameter tended to decrease. However, at fiberizing temperature at constant winding speed, fiber diameter tended to increase. The properties of the prepared spinning fibers were confirmed by optical microscope, tensile strength, modulus and alkali-resistance tests.

이 연구는 코르크보드를 보강하여 건축부재 및 놀이기구의 안전부재 등으로 폭넓게 활용할 것을 목적으로 코르크보드의 중층에 금속, 유리섬유, 탄소섬유를 삽입하여 보강한 3종의 코르크복합보드를 제조하였고, 코르크복합보드의 수분흡수에 따른 치수안정성 및 접착층 박리성능을 조사하였다. 코르크복합보드의 흡수율은 0.37% - 0.45%의 범위에 있었고, 코르크보드에 비해 0.61배 - 0.74배의 낮은 값을 나타내었다. 코르크복합보드의 두께팽창률은 0.92% - 1.58%의 범위에 있었고, 코르크보드 보다 1.4 - 2.4배의 높은 값을 나타내었다. 그러나 이 값들은 일반 목질보드보다 현저히 낮았고, KS규격의 12%이하를 하회하는 것이 확인되었다. 코르크복합보드의 준내수 및 내수침지박리시험후의 접착층박리율은 0%로 전혀 접착층의 박리가 일어나지 않아 우수한 내수성을 나타내었고, 흡수율과 흡수두께팽창률은 상온침지에 비해 다소 증가하였으나, 목질보드에 관한 KS규격을 하회하는 우수한 치수안정성을 나타내는 것이 확인되었다.

In recent, fiber-reinforced composites have been widely used in many fields because of their excellent performance. In order to manufacture lightweight, high-performance, and inexpensive composites various laminated structures were designed. Six types of hybrid composites were fabricated with glass/basalt/aramid fibers by VARTM process. The effect of the laminated structure on the mechanical properties of composites was investigated through impact energy, tensile and bending strength. Compared to other conditions more higher impact energy was obtained when the aramid fibers were in the center position and more higher bending strength was obtained when the fibers are laminated in the order of increasing bending performance from top to bottom. The laminate structure did not affect tensile strength which mainly depends on the property of fibers.

유리섬유강화 모르타르 관을 구성하는 보강섬유는 직교이방성 부재로 간주되며 재료의 성질은 서로 직각을 이루는 두 개의 축을 기준으로 정의된다. 유리섬유 모르타르 관의 구조적 거동 해석을 수행하기 위해서 길이방향과 원주방향의 재료의 역학적 성질, 즉 탄성계수, 전단탄성계수, 포아송비 등이 필요하며 각각의 성질들은 실험을 통해 결정하였다. 이 실험으로부터 구한 각각의 역학적 성질을 적용하여 간소화된 유한요소해석방법을 제안하기 위해 적층판 이론으로부터 유리섬유강화 모르타르 관의 탄성계수를 계산하고, 계산된 탄성계수를 적용하여 유한요소 해석을 수행하였다. 또한, 유한요소해석과 편평시험을 통해 구한 하중-변위 관계를 비교하였으며 ASTM D2412에서 제시하고 하고 있는 관의 강성 값을 유한요소해석과 실험을 통해 예측하여 비교하였다.

GRP관은 연성관으로 분류되며, 지중에서 지반과 함께 외부하중에 저항하는 상호거동을 한다. 또한 국내 설계기준에서는 GRP관의 설계에 대한 명확한 규정을 제시하지 못하고 있으나, AWWA M 45 및 ASTM D 2412에서는 지중매설 GRP관의 관변형에 대한 주요설계변수를 관강성, 지반반력계수, 기초각 등으로 규정하고 있다. 이 연구에서는 지중매설된 연성관의 구조적 거동을 파악하기 위하여 기존 연구에서 수행한 연구결과와 AWWA M 45에서 제시하고 있는 설계식을 이용하여, 관강성, 지 반반력계수, 기초각계수를 변수로 지반-관 상호작용 특성을 검토하였다. 검토결과 지중매설 GRP관의 구조적 거동에 가장 큰 영향을 미치는 설계변수는 지반반력계수이고, 기초각은 180°로 시공하여야 하며, 특히 대구경관에서는 지반의 영향이 더욱 중요한 것으로 나타났다. 따라서 GRP의 안전성을 확보하기 위해서는 시공과정에서 되메움토에 대한 다짐도, 상대밀도, 흙의 종류에 대한 세부적인 규정과 관리가 필요하며, 특히, 헌치부에 대한 시공관리가 이루어져야 할 것으로 판단된다.

전 세계적으로 건설폐기물에 의한 환경문제에 대한 관심이 증가하고 있다. 이에 따라 건설재료들에 대한 재활용방안 에 대한 연구가 많이 진행되고 있다. GFRP는 최근 구조물의 보강에 많이 사용되는 건설 재료이다. 본 연구에는 GFRP를 분쇄하 여 만든 재활용 GFRP파우더(RGP)의 잔골재 대체 가능성을 검토하고자 하였다. RGP는 GFRP의 제작 시 발생되는 GFRP 잉여물을 분쇄하여 사용하였다. RGP의 잔골재 치환율을 20%, 40% 60% 80%로 설정하였다. RGP가 혼합된 시멘트 모르타르의 재료 성능을 검토하기 위하여 압축강도, 쪼갬인장강도 및 휨 강도를 측정하였다. 실험결과, RGP의 혼입으로 시멘트 모르타르의 기초물성이 증가하는 경향이 나타났다. 본 연구결과는 장기적으로 GFRP의 건설재료로의 재활용을 위한 기초자료로 활용이 가능할 것으로 판단된다.

Cured-in-place-pipe(CIPP) is the most adopted trenchless application for sewer rehabilitation to extend the life of the existing sewer without compromising both direct construction and indirect social costs especially applied in the congested urban area. This technology is globally and domestically known to be the most suitable for partial and full deteriorated pipe structure rehabilitation in a sewer system. The typical design of CIPP requires a significant thickness of lining to support loading causing sewage flow interruption and increasing material cost. This paper presents development of a high strength glass fiber composite lining material for the CIPP application and structural test results. The test results exhibit that the new glass fiber composite lining material has 12 times of flexural strength, 6.2 times of flexural modulus, and 0.5 Creep Retention Factor. These test results can reduce lining design thickness 35% at minimum. Even though taking into consideration extra materials such as outer and inner films for actual field applications, the structural capacity of the composite material significantly increases and it reduces 20 percent or more line thickness as compared to the conventional CIPP. We expect that the newly developed CIPP lining material lowers material costs and minimizes flow capacity reduction, and fully replaceable to the conventional CIPP lining materials.

The fatigue characteristics of glass fiber reinforced plastic (GFRP) composites were studied under repeated loads using the finite element method (FEM). To realize the material characteristics of GFRP composites, Digimat, a mean-field homogenization tool, was employed. Additionally, the micro-structures and material models of GFRP composites were defined with it to predict the fatigue behavior of composites more realistically. Specifically, the fatigue characteristics of polybutylene terephthalate with short fiber fractions of 30wt% were investigated with respect to fiber orientation, stress ratio, and thickness. The injection analysis was conducted using Moldflow software to obtain the information on fiber orientations. It was mapped over FEM concerned with fatigue specimens. LS-DYNA, a typical finite element commercial software, was used in the coupled analysis of Digimat to calculate the stress amplitude of composites. FEMFAT software consisting of various numerical material models was used to predict the fatigue life. The results of coupled analysis of linear and nonlinear material models of Digimat were analyzed to identify the fatigue characteristics of GFRP composites using FEMFAT. Neuber’s rule was applied to the linear material model to analyze the fatigue behavior in LCF regimen. Additionally, to evaluate the morphological and mechanical structure of GFRP composites, the coupled and fatigue analysis were conducted in terms of thickness.

Since electric energy is used in industry, mass production and various conveniences are provided. To provide convenience for the construction and operation of such electric energy transmission and distribution facilities, it is increasing that the demand for special purpose vehicles, that is, telescopic aerial work platform vehicles. When working active electric work using the telescopic aerial work platform vehicles, due to active electric work is inevitable, it is essential to ensure insulation performance for the safety of the operator. In this paper, we study the design and development of mechanical properties for filament winding process of glassfiber/epoxy composite, it is required to boom of telescopic aerial work platform vehicles. The glass fiber/epoxy composite filament winding process and its mechanical properties were evaluated to replace the existing ATOS80 boom. By filament winding process it was obtained the mechanical properties required for the design analysis of the glass fiber/epoxy composite boom. Using this, the insulated boom for the 30m class aerial work vehicle was designed and was manufactured by applying the filament winding process. The fabricated composite boom was evaluated by the static strength test to meet the required strength. The maximum displacement was 84mm and the crack occurred at the maximum load of 8981N. It satisfied the maximum lifting load of 4900N and 210mm the maximum displacement required for the boom.

Due to rapid industrialization and urbanization, maintenance of high voltage transmission lines in narrow alleys, complex roads, or old factory areas is required. Since the existing aerial lift vehicle is made of steel, there is a risk of electric shock. Therefore, there is a need for the development of an insulated aerial lift vehicle that can prevent electric shock accidents during electrical work. In particular, the development of an insulated aerial lift vehicle is required in a recent work environment where live line work is inevitable. The development of composite insulation boom for the vertical swing type aerial lift vehicle is studied. The insulated boom was developed by applying glass fiber-epoxy composite and filament winding process. The developed insulated boom was verified by measuring dielectric breakdown strength, surface resistance and volume resistance according to ASTM D149 and ASTM D257.

유한요소법(finite element method)은 다양한 분야에서 재료의 역학적 거동을 더욱더 현실적으로 해석하고 예측하는 방법으로 다양한 분야의 제품 개발에 적용되고 있다. 하지만 섬유배향과 변형률 속도가 역학적 특성에 영향을 미치는 유리섬유 강화 플라스틱 복합재료에 관한 수치해석을 이용한 접근 방법은 현재까지 다소 어려움이 있다. 본 연구의 목적은 고분자, 고무, 금속 등과 같은 다양한 복합재료를 위한 선형, 비선형 다중스케일 재료 모델링 프로그램인 Digimat의 수치해석 재료 모델을 활용하여 유리섬유 강화 플라스틱 복합재료의 역학적 특성을 정의하고 검증하는 것에 있다. 또한 이를 통해 좀더 현실 적으로 고분자 복합재료의 거동을 예측하고자 한다. 이를 위해 다양한 고분자 중 30wt%의 단섬유 질량 비율을 갖는 폴리부 틸렌 텔레프탈레이트(polybutylene terephthalate, PBT)의 섬유배향과 변형률 속도에 따른 인장 특성을 참고문헌을 통해 조사하였다. 또한 Moldflow 프로그램을 사용한 사출해석을 통해 유리섬유 배향 정보를 계산하였으며 이를 매핑(mapping) 과 정을 통해 유한요소 인장 시편 모델에 전달하였다. 대표적인 유한요소 상용 프로그램 중 하나인 LS-DYNA는 유리섬유 배향과 변형률 속도에 따른 복합재료의 인장 특성을 연구하기 위해 Digimat과의 연성해석(coupled analysis)에 활용되었다. 그리고 유리섬유 강화 플라스틱 복합재료를 해석하기 위한 LS-DYNA의 다양한 비등방성(anisotropic) 재료 모델들의 장단점을 서로 비교하고 평가하였다.

In this study, glass fibers are fabricated via a continuous spinning process using manganese slag, steel slag, and silica stone. To fabricate the glass fibers, raw materials are put into an alumina crucible, melted at 1550℃ for 2 hrs, and then annealed at 600℃ for 2 hrs. We obtain a black colored glass. We identify the non-crystalline nature of the glass using an XRD(x-ray diffractometer) graph. An adaptable temperature for spinning of the bulk marble glass is characterized using a high temperature viscometer. Spinning is carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of 1109℃ to 1166℃ , while the winder speed is in the range of 100rpm to 250rpm. We investigate the various properties of glass fibers. The average diameters of the glass fibers are measured by optical microscope and FE-SEM. The average diameter of the glass fibers is 73 μm at 100rpm, 65 μm at 150rpm, 55 μm at 200rpm, and 45 μm at 250rpm. The mechanical properties of the fibers are confirmed using a UTM(Universal materials testing machine). The average tensile strength of the glass fibers is 21MPa at 100rpm, 31MPa at 150rpm, 34MPa at 200rpm, and 45MPa at 250rpm.

PURPOSES: The objective of this study is to evaluate the physical properties of recycled asphalt mixtures reinforced with glass fiber. METHODS: Firstly, mixing design was conducted on recycled asphalt mixture for use of 50% recycled aggregate. Various laboratory tests were performed on four types of recycled asphalt mixtures with different glass fiber content to evaluate the physical properties. The laboratory tests include indirect tensile strength test, dynamic modulus test, Hamburg wheel tracking test and tensile-strength ratio to evaluate cracks, rutting and moisture resistance of mixtures. RESULTS: The indirect tensile strength of fiber reinforced glass increased about 139.4%. As a result of comparing the master curves obtained by the dynamic modulus test, the elasticity was low in the low temperature region and high in the high temperature region when the glass fiber was reinforced. The glass fiber contents of PEGS 0.3%, Micro PPGF 0.1% and Macro PPGF 0.3% showed the highest moisture resistance and rutting resistance. CONCLUSIONS : The test results show that use of glass fiber reinforcement can increase the resistance to cracking, rutting, and moisture damage of asphalt mixtures. It is also necessary to validate the long-term performance of recycled asphalt mixtures with glass fiber using full scale pavement testing and field trial construction.

Recently, there is an increasing the pavement distresses such as rutting with an increase in heavy vehicles on the road in Mongolia. Rutting is the longitudinal depression in the wheel path in asphalt pavements and it causes a hydroplaning and severe safety concern for users. This study aims to develop paving material that can prevent rutting on the road pavement by improving the durability of the asphalt mixture in Mongolia. Therefore, this study was carried out using the technique of reinforcing the material by adding fibers to conventional asphalt mixture. Fibers have been used to reinforce various materials for many decades in various parts of the world. It is generally understood that asphalt is strong in compression and weak in tension. Adding fibers with high tensile strength can help increase the strength of a mixture[1]. A mixture of glass fibers was used in this study to evaluate the performance characteristics. In coordination with the City of Ulaanbaatar, The test section selected in this study was Peace Avenue in Ulaanbaatar. The test section was a bus lane with severe rutting by heavy vehicles. The designated road test section performed cutting and overlay using five asphalt mixtures: Glass Fiber-reinforced Asphalt, Hot Mix Asphalt(10mm, 19mm), Polymer Modify Asphalt(2 types). The performance survey was conducted after the summer. As a result, No noticeable cracks were observed in glass-reinforced mixture section and the rut-depth of the glass-reinforced mixture is lower than other mixtures[2].