• Title/Summary/Keyword: 기능경사재

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Thermo-Elastoplastic Analysis of Ni/Al$_2$O$_3$Heat-Resisting Functionally Graded Composites (Ni/Al$_2$O$_3$기능경사 내열복합재의 열-탄소성 해석)

  • 조진래;김병국;하대율
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.1
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    • pp.11-19
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    • 2001
  • 기능경사재(FGM)는 구성 물질의 체적분율(volume fraction)이 복합재 전체에 걸쳐 연속적 그리고 기능적으로 분포되어 있어, 기존의 이종물질 접합식(bi-material-type) 복합재보다 현저히 우수한 열기계적 특성을 가진다. 하지만, 기능경사 내열복합재의 열-탄소성 거동은 체적분율의 분포형태와 경사층이 차지하는 상대두께비에 따라 절대적으로 좌우된다. 본 연구는 기능경사 내열복합재의 열-탄소성 특성의 이들 두 설계인자에 대한 파라메트릭 FEM해석을 다룬 것이다. 열-탄소성 이론과 유한요소 근사화에 따라 연구용 2차원 FEM 프로그램을 개발하고, 대표적인 3층 구조의 2차원 기능경사 내열복합재의 열-탄소성 특성을 설계변수의 다양한 조합에 따라 분석하였다.

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Comparative Numerical Analysis of Homogenized and Discrete-Micromechanics Models for Functionally Graded Materials (기능경사재를 위한 균질화와 이산화-미시역학 모델에 대한 비교 수치해석)

  • Ha, Dae-Yul;Lee, Hong-Woo;Cho, Jin-Rae
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.399-404
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    • 2000
  • Functionally graded materials(FGMs) involve dual-phase graded layers in which two different constituents are mixed continuously and functionally according to a given volume fraction. For the analysis of their thermo-mechanical response, conventional homogenized methods have been widely employed in order to estimate equivalent material properties of the graded layer. However, such overall estimations are insufficient to accurately predict the local behavior. In this paper, we compare the thermo-elastic behaviors predicted by several overall material-property estimation techniques with those obtained by discrete analysis models utilizing the finite element method, for various volume fractions and loading conditions.

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Study on the Volume Fraction Optimization of Functionally Graded Heat-Resisting Composites (기능경사 내열 복합재의 체적분율 최적화에 관한 연구)

  • Jo, Jin-Rae;Ha, Dae-Yul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.6
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    • pp.988-995
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    • 2001
  • Functionally graded materials(FGMs) are highlighted to be suitable for high temperature engineering due to their continuous distribution of material properties. In this paper, an optimal design is executed for determining the optimal material volume distribution pattern that minimizes the steady-state thermal stress of FGM heat-resisting composites. The interior penalty function method and the golden section method are employed as optimization techniques while the finite element method is used for thermal stress analysis. Through numerical simulations we suggest the volume fraction distributions that considerably improve initial thermal stress distributions.