• Title, Summary, Keyword: 적층배열

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Layup Optimization for Composite Laminates with Discrete Ply Angles (이산 섬유 배열각을 이용한 복합재료 적층 평판의 최적 설계)

  • Kim, Tae-Uk
    • Proceedings of the KSME Conference
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    • pp.734-739
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    • 2001
  • In this paper, an algorithm for stacking sequence optimization which deals with discrete ply angles is used for optimization of composite laminated plates. To handle discrete ply angles, the branch and bound method is modified. Numerical results show that the optimal stacking sequence is found with fewer evaluations of objective function than expected with the size of feasible region, which shows the algorithm can be effectively used for layup optimization of composite laminates..

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In-situ Patterning of Magnetic Particles in Microfluidic Channels by Forward/Reverse Local Magnet Arrangement (국소 자기장의 순/역 배열을 이용한 미세유체 채널 내에서의 강자성 입자 패턴 형성)

  • Park, Hyoun-Hyang;Lee, Ji Hae;Yoo, Yeong Eun;Kim, Jung-Yup;Chang, Sunghwan
    • Transactions of the KSME C: Technology and Innovation
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    • v.3 no.3
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    • pp.217-223
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    • 2015
  • The patterning of microbead in microfluidics channel is a practical technique for application in bio and medical areas. An approach is described for a direct patterning of magnetically active microbeads in microfluidic devices without inner structure. Local magnet arrangements - flat arrangement and stack arrangement - contacting same poles or opposite poles of magnet were utilized for generating trapping magnetic fields. The arrangement of magnets contacting same poles generated isolated patterns by repelling of magnetic field. The flat arrangement of vertically reverse magnet arrays shaped trapping patterns repelling magnetic field line between same poles. Spatially, the stack compositions of magnet arrangements allow diverse isolated trapped patterns of magnetic particles. Trapped magnetic particles in fluidic channels were stable on the $18m{\ell}/hr$ flow conditions and magnetic force of 1.08 mT in the all experiments. This experimental study suggests the simple and versatile methods to pattern magnetic particles, and has potential of wide application to bio and medical area.

진공단열재의 단열성능을 개선을 위한 Glass Fiber 수평 배열(다층구조) 기술 개발

  • Han, Jeong-Pil;Hwang, Seung-Seok;Jeon, Seung-Min;Min, Byeong-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.207-207
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    • 2012
  • 진공단열재는 폴리우레탄 폼 대비 10배 이상의 단열성능을 갖는 고효율 단열재로서 고차단성 필름 봉투 내부에 무기 소재를 진공감압시켜 대류에 의한 열전달을 최소화시킨 차세대 단열재이다. 특히 진공단열재에 있어 열전달의 경로는 전도에 의한 효과가 가장 크므로, 진공단열재 내부의 Glass Fiber 심재의 최적화 설계에 따라 단열 성능을 극대화 시킬 수 있다. 이에, 본 연구에서 GLass Fiber의 배열에 따른 성능 비교 평가를 통해, 전도의 특성을 최소화 시킬 수 있는 Glass Fiber의 배열 및 다층 적층 구조를 통해 성능 개선 효과를 고찰 하였다.

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Prediction of Fracture Strength of Woven CFRP Laminates According to Fiber Orientation (평직 CFRP 적층복합재료의 섬유배열각도에 따른 파괴강도 예측)

  • Kang, Min-Sung;Park, Hong-Sun;Choi, Jung-Hun;Koo, Jae-Mean;Seok, Chang-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.8
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    • pp.881-887
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    • 2012
  • CFRP composite materials have been widely used in various fields of engineering because of their excellent properties. They show high specific stiffness and specific strength compared with metallic materiasl. Woven CFRP composite materials are fabricated from carbon fibers with two orientation angles ($0^{\circ}/90^{\circ}$), which influences the mechanical properties. Therefore, woven CFRP composite materials show different types of fracture behavior according to the load direction. Therefore, the fracture behavior of these materials needs to be evaluated according to the load direction when designing structures using these materials. In this study, we evaluate the fracture strength of plain-woven CFRP composite materials according to the load direction. We performed tests for six different angles (load direction: $0^{\circ}/90^{\circ}$, $30^{\circ}/-60^{\circ}$, $+45^{\circ}/-45^{\circ}$) and estimated the fracture strength for an arbitrary fiber angle by using the modified Tan's theory and harmonic function.

Study on Fastened Properties by Applied to CFRP Laminates of Subminiature Screw (초소형나사의 CFRP 적층판 적용에 따른 체결특성에 관한 연구)

  • Choi, Byung Hui;Kim, Ho Joong;Kim, Ji Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.11
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    • pp.1239-1243
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    • 2014
  • This paper presents the application of carbon-fiber-reinforced polymer (CFRP) for the damage absorption and optimal design of portable smart devices to close in life. CFRP specimens are subjected to a tensile test to estimate their mechanical properties in terms of the stacking angles. Further, the screw reverse torque and screw torque at each stacking angle are determined using a torque tester after tapping holes on the CFRP specimens. Two experiments are performed for comparing their results in order to determine optimal conditions. In the tensile test, a woven specimen is found to have the highest strength and stiffness. In the case of the woven specimen, no difference is observed even when it is applied to prevent loosening of the coating. And average result value was excellent.

Optimal Ply Design of Laminated Composite Cantilever plate Considering Vibration (진동을 고려한 복합적층 외팔평판의 최적적층설계)

  • Gu, K.M.;Noh, Y.H.;Kim, D.Y.;Hong, D.K.;Ahn, C.W.;Han, G.J.;Park, H.S.
    • Proceedings of the KSME Conference
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    • pp.1660-1665
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    • 2003
  • On this study, we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite cantilever plate by each aspect ratio. A finite element analysis on the CFRP laminated composite cantilever plate using orthogonal array is carried out, and the results are compared with those obtained by modal testing.

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A Study on the Drilling of Composites laminates with respect to Stacking sequences (적층구성이 다른 복합재의 드릴 가공에 관한 연구)

  • 정성택;박종남;조규재;심재기
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.180-185
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    • 2002
  • In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods, etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 6 stacking sequences, and the specimens are drilled with 4 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

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Bending Creep Performances of Hybrid Laminated Woods Composed of Wood-Wood Based Boards (목재와 목질보드 복합적층재의 휨 크리프 성능)

  • Park, Han-Min;Kang, Dong-Hyun;Choi, Yoon-Eun;Ahn, Sang-Yeol;Ryu, Hyun-Su;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.1
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    • pp.1-10
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    • 2010
  • In this study, to study an effective use and improve strength performances of woods and wood-based materials, three-ply hybrid laminated woods which are composed of spruce in the face and three kinds of wood-based boards (MDF, PB, OSB) in the core were manufactured, and the effect of constitution elements used for the core laminae on bending creep performances was investigated. The shape of creep curves showed exponential function plots which the upper right side was increased, and differed among the kinds of wood-based boards used for the core laminae of hybrid laminated wood. The creep deformation perpendicular to the grain of faces of hybrid laminated woods was in order $C_{\perp}$(P) > $C_{\perp}$(M) > $C_{\perp}$(O) with PB, MDF and OSB in the core, respectively. It was found that the creep deformation arranged with OSB in the core had 2 times smaller than those arranged with MDF and PB in the core. By hybrid laminating, the creep deformation of spruce perpendicular to the grain was markedly decreased. On the other hand, the creep deformation parallel to the grain of the faces ($C_{\parallel}$ type) of hybrid laminated woods was in order $C_{\parallel}$(P) > $C_{\parallel}$(O) > $C_{\parallel}$(M) with PB, OSB and MDF in the core. The ratios among three hybrid laminated woods were considerably decreased, especially the difference between $C_{\parallel}$(P) and $C_{\parallel}$(O) hybrid laminated woods arranged with PB and OSB in the core was very small. These values showed 0.108~0.464 times smaller than creep deformation of three wood-based boards and it was found that creep deformation of three wood-based boards was considerably decreased by hybrid laminating. Creep anisotropy of hybrid laminated woods was greater in creep deformation than in initial deformation, whereas it was found that the values was much smaller than that of spruce parallel laminated woods.

Prediction of Effective Properties of Laminated Plain Weave Textile Composites (적층각을 가지는 평직복합재료 적층판의 등가물성치 예측)

  • U,Gyeong-Sik;Seo,Yeong-Uk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.10
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    • pp.10-20
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    • 2003
  • In this study, the effective properties were numerically calculated for laminated plain weave textile composites with arbitrary s tacking orientation angles. A single-field macroelement with modified sub-domain integration was used in the analysis to reduce computer resource requirement while efficiently accounting for the internal microstructure. A sample calculation procedure based on the Monte Carlo method was employed to consider the random shift between the layers. Results showed that a significant deviation occurred when the orientation angles were near 0 deg for extensional modulus and Poisson's ratio and 45 deg for the shear modulus. It was also found that the average properties calculated by the 2-layer numerical specimen had large differences compared to the CLT results, which indicated that a caution must be needed when designig of thin plain weave composite structures.

Mesoporous Carbon Electrodes for Capacitive Deionization (축전식 탈염 공정을 위한 메조포러스 탄소 전극)

  • Lee, Dong-Ju;Park, Jin-Soo
    • Journal of the Korean Electrochemical Society
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    • v.17 no.1
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    • pp.57-64
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    • 2014
  • Carbon electrodes for capacitive deionization were fabricated through mixing two different carbon powders (activated carbon powder, carbon black) with different particle sizes to investigate physical or electrochemical properties and finally desalination performances of the electrodes with various compositions of two carbon powders in weight and were compared with the electrode consisting of activated carbon. As a result, the electrode structure became more packed as increasing the amount of carbon black and resulted in 10% increase in mesopore fraction. The specific capacitance obtained from cyclic voltammograms of various electrodes showed that the electrode containing carbon black only had 107.4 F/g, while the specific capacitance of the electrode having more amount of carbon black increased and was higher than the one having no carbon black. The results of desalination runs in a capacitive deionization cell exhibited that the electrode having the highest amount of carbon black (1 wt%) in this study had the highest desalting efficiency, and no significant pH variation was observed during the runs. It was analyzed using accumulated charge that the fraction of non-Faraday current increased as the amount of carbon black increased in the electrodes. It can be concluded that the addition of carbon black changed the electrode structure resulting in an increase in the fraction of mesopore and finally enhanced the desalting efficiency by decreasing Faraday current.