• Title, Summary, Keyword: Composite

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Analysis of seismic behavior of composite frame structures

  • Zhao, Huiling
    • Steel and Composite Structures
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    • v.20 no.3
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    • pp.719-729
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    • 2016
  • There are great needs of simple but reliable mechanical nonlinear behavior analysis and performance evaluation method for frames constructed by steel and concrete composite beams or columns when the structures subjected extreme loads, such as earthquake loads. This paper describes an approach of simplified macro-modelling for composite frames consisting of steel-concrete composite beams and CFST columns, and presents the performance evaluation procedure based on the pushover nonlinear analysis results. A four-story two-bay composite frame underground is selected as a study case. The establishment of the macro-model of the composite frame is guided by the characterization of nonlinear behaviors of composite structural members. Pushover analysis is conducted to obtain the lateral force versus top displacement curve of the overall structure. The identification method of damage degree of composite frames has been proposed. The damage evolution and development of this composite frame in case study has been analyzed. The failure mode of this composite frame is estimated as that the bottom CFST columns damage substantially resulting in the failure of the bottom story. Finally, the seismic performance of the composite frame with high strength steel is analyzed and compared with the frame with ordinary strength steel, and the result shows that the employment of high strength steel in the steel tube of CFST columns and steel beam of composite beams benefits the lateral resistance and elasticity resuming performance of composite frames.

Selection Methodology of Tool for Co-cured Composite Materials (동시경화용 복합재료의 특성에 따른 금형의 선택방법)

  • 홍중표;이종옥;이원곤;홍정수;지우석;조한준
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.183-188
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    • 2002
  • Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

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Effect of molding condition on tensile properties of hemp fiber reinforced composite

  • Takemura, K.;Minekage, Y.
    • Advanced Composite Materials
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    • v.16 no.4
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    • pp.385-394
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    • 2007
  • In this study, the effect of molding condition on the tensile properties for plain woven hemp fiber reinforced green composite was examined. The tensile properties of the composite were compared with those of the plain woven jute fiber composite fabricated by the same process. Emulsion type biodegradable resin or polypropylene sheet was used as matrix. The composites were processed by the compression molding where the molding temperature and its heating time were changed from 160 to $190^{\circ}C$ and from 15 to 25 min, respectively. The following results were obtained from the experiment. The tensile property of hemp fiber reinforced polypropylene is improved in comparison with polypropylene bulk. The strength of composite is about 2.6 times that of the resin bulk specimen. Hemp fiber is more effective than jute fiber as reinforcement for green composite from the viewpoint of strength. The molding temperature and time are suitable below $180^{\circ}C$ and 20 min for hemp fiber reinforced green composite. Hemp fiber green composite has a tendency to decrease its tensile strength when fiber content is over 50 wt%.

Structural Design and Analysis of Composite Parts for Small-scaled Hingeless Hub System of Helicopter (헬리콥터용 힌지없는 축소 복합재료 허브부품 구조 설계 및 해석)

  • Kim, Deog-Kwan;Joo, Gene
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.173-176
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    • 2002
  • This paper describes the design procedure of composite parts for hingeless hub system of helicopter. These composite parts are composed of flexure and sleeve. The design of this composite flexure is an important technique in hingeless hub system since the rotor system stability and dynamic characteristics depends on this flexure characteristics. The objective of this research is to replace the existing metal hub parts with composite to improve the performance and stability. First, the coupon test of candidate composite material for hub parts was conducted. The hub parts was designed based on test results and the manufacturing possibility by using Fiber Placement System(FPS) was checked. Also the dynamic analysis and stress analysis of composite hub parts was conducted. Through this research, we will find out the possibility of replacing existing metal hub parts with composite.

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Application of silk composite to decorative laminate

  • Kimura, Teruo;Aoki, Shinpei
    • Advanced Composite Materials
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    • v.16 no.4
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    • pp.349-360
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    • 2007
  • Recently, natural fiber reinforced composite is attracting attention and considered as an environmentally friendly material. Usually cellulosic fibers are used to reinforce the composites, but some protein fibers such as silk and wool serve the same purpose. In this paper, we proposed a method of producing artistic composite from artistic fabric by using silk fiber reinforced biodegradable plastic, which is designated as 'silk composite', for reinforcement. In order to expand applications of the silk composite, we performed the compression molding of decorative laminates with woody material, which was selected as a core material, and examined the properties of molded decorative laminates with various content of the silk composite. Since plywood and medium-density fiberboard (MDF) are widely used for decorative laminates, we selected them as core materials. As a result, flexible decorative laminates with high flexural strength were obtained by compounding the silk composite with wood materials.

Establishment of Aerospace Composite Materials Data Center for Qualification

  • Lee, Ho-Sung;Rhee, Seung Yun;Yoon, Jong-Hoon;Yoo, Joon-Tae;Min, Kyung Ju
    • Composites Research
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    • v.28 no.6
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    • pp.402-407
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    • 2015
  • It is well known that the polymer matrix composite materials have good specific strength, making them appropriate for use in transport vehicle. Since the property of composite materials can be obtained only after manufacturing parts, the property depends on greatly on the fabrication process, which is different from metallic system. Therefore, in order to use composite materials for aircraft, the certifying agency requires a robust database with extensive tests and proof of the process unlike metals. Recently developed material qualification methodology by NCAMP (National Center for Advanced Materials Performance) has been accepted by FAA and EASA and can be applied to type certificate reducing time and cost of developing a composite materials database for aircraft application. This paper summarizes a study to establish the composite materials database to apply the NCAMP methodology to composite materials characterization for composite aircraft and to provide the effective materials database through Aerospace Composite Materials Data Center to be approved by Korea Civil Aviation Certification Agency.

A simplified approach for fire-resistance design of steel-concrete composite beams

  • Li, Guo-Qiang;Wang, Wei-Yong
    • Steel and Composite Structures
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    • v.14 no.3
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    • pp.295-312
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    • 2013
  • In this paper, a simplified approach based on critical temperature for fire resistance design of steel-concrete composite beams is proposed. The method for determining the critical temperature and fire protection of the composite beams is developed on the basis of load-bearing limit state method employed in current Chinese Technical Code for Fire safety of Steel Structure in Buildings. Parameters affecting the critical temperature of the composite beams are analysed. The results show that at a definite load level, section shape of steel beams, material properties, effective width of concrete slab and concrete property model have little influence on the critical temperature of composite beams. However, the fire duration and depth of concrete slab have significant influence on the critical temperature. The critical temperatures for commonly used composite beams, at various depth of concrete and fire duration, are given to provide a reference for engineers. The validity of the practical approach for predicting the critical temperature of the composite beams is conducted by comparing the prediction of a composite beam with the results from some fire design codes and full scale fire resistance tests on the composite beam.

Continuous Curing and Residual Stresses of Thick Composite Cylinders (두꺼운 복합재료 실린더의 생산 및 열응력 해석)

  • Kim, Cheol
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.49-52
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    • 2000
  • A new composite manufacturing technique which combines winding and curing together is studied and analyzed. This method is especially suited to the manufacture of thick composite materials in which thermal spiking is a common problem. An experimental apparatus was designed and built for use with a filament winder to continuously cure a thick composite cylinder. A hoop-wound composite cylinder with 152 mm wall thickness was manufactured and embedded thermocouples and strain gages were monitored throughout the cure process. The experimental data were compared with analytical results.

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Composite Aerostatic Spindle (복합재료 공기정압 주축부)

  • 방경근;장승환;이대길
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.134-138
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    • 1999
  • For the stable operation of high speed aerostatic spindle, the low rotational inertia and high damping ratio of spindle shafts as well as high fundamental natural frequency are indispensable. Conventional steel spindles are not appropriate for very high speed operation because of their high rotational inertia and low damping ratio. In this study, the composite spindles with aerostatic bearing were designed and manufactured with carbon fiber/epoxy composite. The fundamental natural frequency of the composite spindle was evaluated through the modal testing.

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Analysis of Thick-walled Composite Channel Beam Under Flexural Loading (굽힘 하중을 받는 두꺼운 채널 빔의 해석)

  • 최용진;전흥재;변준형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.69-73
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    • 2003
  • A open section thick composite beam model is suggested in this study. In the model, the primary and secondary warping and transverse shear effects are incorporated. The rigidities associated with thick channel composite beam and thin channel composite beam are obtained and compared. The results show that the difference among rigidities of the thick and thin composite beams increase as the wall thickness increases.

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