• Title/Summary/Keyword: 경사기능 재료

Search Result 133, Processing Time 0.032 seconds

Evaluation of Response Variability of Functionally Graded Material Beam with Varying Sectional Area due to Spatial Randomness in Elastic Modulus along Axial Direction (기능경사재료 변단면 보에서 축방향 탄성계수의 공간적 불확실성에 의한 응답변화도 평가)

  • Noh, Hyuk Chun
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.27 no.3
    • /
    • pp.199-206
    • /
    • 2014

  • In this paper, a scheme to evaluate the response variability for functionally graded material (FGM) beam with varying sectional area is presented. The randomness is assumed to appear in a spatial domain along the beam axis in the elastic modulus. The functionally graded material categorized as composite materials, however without the drawbacks of delamination and occurrence of cracks due to abrupt change in material properties between layers in the conventional composite materials. The functionally graded material is produced by the gradual solidification through thickness direction, which endows continuous variation of material properties, which makes this material performs in a smooth way. However, due to difficulties in tailoring the gradients, to have uncertainty in material properties is unavoidable. The elastic modulus at the center section is assumed to be random in the spatial domain along the beam axis. Introducing random variables, defined in terms of stochastic integration, the first and second moments of responses are evaluated. The proposed scheme is verified by using the Monte Carlo simulation based on the random samples generated employing the spectral representation scheme. The response variability as a function of correlation distance, the effects of material and geometrical parameters on the response variability are investigated in detail. The efficiency of the proposed scheme is also addressed by comparing the analysis time of the proposed scheme and MCS.

  • https://doi.org/10.7734/COSEIK.2014.27.3.199 인용 PDF KSCI

Temperature-Dependent Stress Analysis of Rotating Functionally Graded Material Gas Turbine Blade Considering Operating Temperature and Ceramic Particle Size (운전온도와 세라믹 입자크기를 고려한 회전하는 경사기능성 가스터빈 블레이드의 응력해석)

  • Lee, Ki Bok;Yoo, Hong Hee
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.38 no.2
    • /
    • pp.193-203
    • /
    • 2014

  • Temperature-dependent stress analysis and heat transfer analysis of a rotating gas turbine blade made of functionally graded materials (FGMs) are presented considering turbine operating temperature and ceramic particle size. The material properties of functionally graded materials are assumed to vary continuously and smoothly across the thickness of the thin-walled blade. For obtaining system stiffness reflecting these characteristics, the one-dimensional heat transfer equation is applied along the thickness of the thin-walled blade for determining the temperature distribution. Using the results of the temperature analysis, the equations of motion of a rotating blade are derived with hybrid deformation variable modeling method along with the Rayleigh-Ritz assumed mode methods. The validity of the derived rotating blade model is evaluated by comparing its transient responses and temperature distribution with the results obtained using a commercial finite element code. The maximum tensile stress with operating speed and gradient index are obtained. Furthermore, the gradient index that minimizes blade temperature was investigated.

  • https://doi.org/10.3795/KSME-A.2014.38.2.193 인용 PDF KSCI

A Study on Design of Functionally graded Materials (경사기능재료의 설계에 관한 연구)

  • 최덕기;경사기
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.6 no.2
    • /
    • pp.144-154
    • /
    • 1998

  • A functionally graded material is a nonhomogeneous material, which is composed of several different materials to maintain structural rigidity and endure high temperature loads. An analytical method is presenter to solve the unsteady heat conduction equation for nonhomogeneous materials. A one-dimensional infinite plate made of functionally graded material is considered. The approximate Green's function solution is derived and to be used to obtain the temperature distribution them the stress distributions may be obtained. The volume fraction, the porosity, the stress difference, and the stress ratio are the design parameters and are to be used to set up a systematic design procedure.

  • PDF