• 한국기계가공학회지
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• 제17권2호
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• pp.137-144
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• 2018

This study describes the 3D design and analysis of a composite insulation boom of an aerial work platform for electric work. Structural analysis of the composite insulation boom was performed using ANSYS and the total deformation, equivalent stress, and normal elasticity were investigated at 150 mm, 500 mm, 1,000 mm, and 1,500 mm using a mounted strain gauge. The results of the analysis and test were similar in a linearly increasing slope and the difference in the strain value was about 10%. This difference depends on the compressive force in the manufacturing process.

• 한국항해항만학회지
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• 제32권9호
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• pp.699-703
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• 2008

Fiber reinforced plastics (FRP) have been widely used because of their high specific strength, high specific stiffness and etc. Although these kinds of FRP have various merits in applications, it has been had one of the complicated problems to manufacture their wooden mold. For these reasons, the simple methods to manufacture the mold required in the FRP industries. To improve these kinds of problems, the molding system using composite materials was developed. By this new manufacturing techniques and high functional FRP composite mold was built. Comparing with wooden mold, the process efficiencies of frame manufacturing process and inner mold manufacturing process were improved approximately 40% and 70%, respectively.

• 대한기계학회논문집A
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• 제30권7호
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• pp.794-799
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• 2006

In recent years, the use of natural fiber as reinforcement in polymer composites to replace synthetic fiber such as glass fiber is receiving increasing attention. Because of increasing usage according to the high demand, the cost of thermoplastic has increased rapidly over the past decades. We used a thermoplastic polymer(polypropylene) as the matrix and a lignocellulosic material(rice-husk flour) as the reinforcement filler to prepare a particle-reinforced composite to examine the possibility of using lignocellulosic material as reinforcement filler and to determine data of test results for physical, mechanical and morphological properties of the composite according to the reinforcement filler content in respect to thermoplastic polymer, In this study, PLA/PP rice-husk fiber-reinforced thermoplastic composites that made by the hot press molding method according to appropriate manufacturing process was evaluated as mechanical properties.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.304-312
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• 1996

Concepts, methods and tools for interactive CAD-based concurrent engineering design optimization of mechanical/structural systems and components which are critical in terms of cost development time, functionality and quality, are presented. The emphasis is on implementation of methods and capabilities for the optimization of composite structural system, and the integration of design process and manufacturing process of composite structures into standard CAD-based concurrent engineering environment The optimization of composite fuselage structures are performed under concurrent engineering environment for the example.

• Composites Research
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• 제22권2호
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• pp.30-36
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• 2009

본 논문에서는 헬리콥터 착륙장치를 위한 복합재료 토크링크를 개발하기 위한 설계 기법을 제시하였다. 복합재 토크링크는 헬리콥터 착륙장치의 충격흡수부의 정렬을 위해 장착되는 장치로서 가벼우면서도 강성이 커서 외부하중에 대해 최소의 변형량을 가져야 한다. 또 가격적인 측면을 고려한 복합재 구조물 제조 공정(RTM: 수지충전공정)이 반영되어 대량생산이 가능한 구조 및 형태를 가져야 한다. 본 논문에서는 복합재 구조물 제조 공정과 동일한 공정으로 시편을 제작하여 설계에 필요한 기계적 특성을 얻었으며, 유한요소해석을 통하여 복합재 토크링크에 대한 최적 형상설계를 수행하였다. Lug 형태를 가지는 두꺼운 복합재료 구조물인 복합재료 토크링크의 설계를 위해서는 ABAQUS의 3D Layered Solid 요소로 구성된 유한요소모델을 활용하여 복합재료의 두께방향을 포함한 강도해석을 수행하였으며, Rigid-Deform 구속조건의 접촉문제를 고려한 비선형 정적 해석을 반복적으로 수행하여 주어진 정강도 요구조건을 만족시키는 복합재 토크링크를 설계하였다.

• Composites Research
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• 제35권4호
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• pp.242-247
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• 2022

본 연구는 기존의 폐CFRP를 재활용하여 얻은 재생 탄소섬유를 다시 CFRP 제조에 활용하는 대신 탄소를 모재로 구성하는 탄소/탄소 (Carbon/Carbon, C/C) 복합소재를 제조하는 원료로 활용하기 위한 것이다. 먼저 일반적으로 많이 활용되는 에폭시수지 복합재료의 열분해 공정에 산화-불활성 분위기 변환 기술을 적용하여 1~2% 수준의 잔탄률을 19%까지 향상시켰으며, 이를 통해 에폭시수지 활용 C/C 복합재료 제조 가능성을 확인하였다. 다만, 산화-불활성 분위기 제어를 통한 열분해 공정으로 얻은 탄소의 경우 산소결합도가 높아 추후 개선 연구가 필요한 것으로 나타났다. 또한, 폐CFRP를 열분해 열처리 후 파쇄 및 해쇄 공정을 통해 단섬유 C/C 복합재료 시험편을 제조하였으며 이에 대한 기계적 물성 평가를 통해 최적 공정 조건을 도출하였다.

• 한국기계가공학회지
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• 제16권5호
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• pp.25-30
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• 2017

Carbon-fiber-reinforced plastic (CFRP) composite materials have been widely used in various industrial fields because the design variables can be adjusted according to the application of the required structure. Thermosetting and thermoplastic resins are used as the base materials of CFRP composites for the lightweight construction of automotive components. Thermoplastics have several advantages such as no curing and recyclability compared to thermosetting resin. In this study, CFRP composites were made using the Long-Fiber Thermoplastic-Direct (LFT-D) process. The LFT-D process includes an in-line production system that directly impregnates a thermoplastic resin, extrudes the composite material, and molds it. This process increases the strength and decreases the molding time. The tensile strength characteristics on the mechanical properties of CFRP were analyzed according to the parameters of LFT-D based on thermoplastics. To analyze the properties of CFRP, the specimens were prepared based on the tensile test standard ASTM 3039 of composite materials.

• 한국기계가공학회지
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• 제10권1호
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• pp.38-46
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• 2011

A study was performed to investigate the dynamic behaviors of fiber-reinforced composite materials subjected to transversely low-velocity impact. For this purpose, the simulation of modified beam finite element based on higher order beam theory for two(isotropic and anisotropic) materials is carried out according to the changes of material property, stacking sequence, geometric dimension and impact velocity of steel ball, etc. Main composite materials for simulation are composed of $[0^{\circ}/90^{\circ}/0^{\circ}/-90^{\circ}/0^{\circ}]_{2s}$, $[0^{\circ}/90^{\circ}/0^{\circ}/-90^{\circ}/0^{\circ}]_s$ and $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_{2s}$, $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_s$ stacking sequences. The effectiveness of this simulation for qualitative and quantitative evaluations in composite materials subjected to foreign object impact was established.

• 한국기계가공학회지
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• 제14권1호
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• pp.105-110
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• 2015

In this study, a high-speed procedure to be used in composite molding technology is developed for the production of a hybrid supercapacitor in a progressive and revolutionary current in a production system, as are the related operating conditions. Mold parts with solid modeling, the ease of programming of future mold product designs, tolerance management, and pre-explode tests by the building of a progressive die design system using Cimatron_E10 Die Design Software for the strip layout are done. The capacity of the super-hybrid composite mold design will save time and money through its verification of the manufacture of molds. We plan to apply this to future related products for production cost savings of more than 30% achieved by considering the components of the production costs, labor, and material costs of production as compared to conventional production methods.

• 한국기계가공학회지
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• 제18권12호
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• pp.28-37
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• 2019

Due to their flexible tailoring qualities, composites have become fascinating materials for structural engineers. While the research area of fiber-reinforced composite materials was previously limited to synthetic materials, natural fibers have recently become the primary research focus as the best alternative to artificial fibers. The natural fibers are eco-friendly and relatively cheaper than synthetic fibers. The main concern of current research into natural fiber-reinforced composites is the prediction and enhancement of the effective material properties. In the present work, finite element analysis is used with a numerical homogenization approach to determine the effective material properties of jute fiber-reinforced epoxy composites with various volume fractions of fiber. The finite element analysis results for the jute fiber-reinforced epoxy composite are then compared with several well-known analytical models.