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Solution of Coupled Thermoelasticity Problem in Rotating Disks with Constant and Variable Thickness

Entezari, Ayoob | 2017

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 49958 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Kouchakzadeh, Mohammad Ali
  7. Abstract:
  8. The main purpose of this dissertation is to study thermoelastic behaviors in rotating disks subjected to thermal shock loads based on the generalized and classic theories of coupled thermoelasticity. To this end, this research has been carried out in two stages. In the first stage, thermoelasticity problems in an axisymmetric rotating disk with constant thickness made of a homogeneous isotropic material are analytically solved. In this stage, based on the classical and generalized coupled theories, and dynamic and quasi-static uncoupled theories, an analytical method based on the Fourier-Bessel transform is employed to obtain the thermoelastic solutions. Then, closed-form formulations are presented for temperature and displacement fields. Since, the analytical solution is not always feasible, the finite element (FE) method can be employed for more sophisticated coupled thermoelasticity problems. Accordingly, in the second stage of the research, a novel refined 1D Galerkin finite element approach with 3D-like accuracies are developed for theories of coupled thermoelasticity. Then, the developed FE models are applied for a 3D solution of the dynamic generalized coupled thermoelasticity problem in variable thickness disks made of a functionally graded material (FGM). Use of the reduced models with low computational costs may be of interest in a laborious time history analysis of the dynamic problems. The obtained analytical and numerical solutions are in good agreement with the results available in the literature. It is further shown that the proposed analytical and FE methods are quite efficient with very high rate of convergence. Time histories of temperature, displacements and stresses, propagation of the thermoelastic waves, the wave reflection from the boundaries are shown and discussed. Likewise, using the FE models, the solutions have been represented as contour plots to highlight 3D capabilities of the models. In addition, effects of coupling parameter, relaxation time, angular velocity and material composition profile in FGM on temperature, displacement and stress fields are investigated
  9. Keywords:
  10. Rotating Disks ; Analytical Method ; Finite Element Method ; Functionally Graded Materials (FGM) ; Thermoelastic Coupling

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