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Vibration and Buckling Analysis of Thick FGM Conical Shells Under Variable Thermal and Pressure Distributions, Considering Initial Geometric Imperfections Using a Higher Order TheoryVibration and Buckling Analysis of Thick FGM Conical Shells Under Variable Thermal and Pressure Distributions, Considering Initial Geometric Imperfections Using a Higher Order Theory

Rahmanian, Mohammad | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42301 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Dehghani Firoozabadi, Rouhollah
  7. Abstract:
  8. The current study is dedicated to free vibration and buckling analysis of thick FGM conical shells conveying hot flows with the consideration of initial geometric imperfections. To this end, the higher order governing equations of motion and the corresponding boundary conditions are derived using Hamiltonian formulations. Due to the solution procedure of Frobenius series expansion, the differential form of equations is obtained by applying by part integration to the integral form of equations of motion. Radial and longitudinal temperature distributions are considered while pressure distribution and geometric imperfection variations are found to be in longitudinal direction, only. The final solution is divided into two major sections, say static and dynamic. In the first portion, pre-stresses due to thermal and mechanical loadings are obtained, to be used in the stability analysis. Having derived the pre-stresses, the critical thermal/mechanical distribution coefficients are obtained. Various geometrical parameters’ effect on the natural frequencies and buckling loads are investigated. Functionally graded materials of ceramic-metal combinations are investigated with different power law indexes. Uniform and linear Temperature distributions across thickness are also employed in thermal buckling analysis. Any linear temperature distribution is obtained by solving the conduction heat transfer equation across the thickness. Some other studies on the effect of boundary conditions on the dynamic behaviors of the conical shells are also conducted. Assuming isentropic flows in the conical shell and using the related relations, the temperature and pressure distributions for later usages can be obtained. The last but not the least is that the dominant advantage of the proposed method besides its swiftness is the analytical and exact solution to the problem
  9. Keywords:
  10. Vibration ; Conical Shell ; Functionally Graded Materials (FGM) ; Thermal Instability ; High Order Shear Theory

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