الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Functionally graded materials (FGMs) are at the forefront of modern material science, offering unprecedented versatility in engineering applications. This thesis, titled ”Thermoelastic Analysis of Thick Cylindrical FGM Pressure Vessels with Variable Parameter” investigates the mechanical and thermal behavior of these vessels using both analytical and numerical methods. The primary objective is to comprehensively analyze stress and strain distributions, considering time-dependent internal pressure and transient temperature gradients along the cylinder’s radius.
A notable aspect of this study is the simultaneous examination of transient thermal and time-dependent mechanical effects on FGM pressure vessels, which is crucial for understanding the structural integrity of these systems under realistic operational conditions. Unlike previous studies that often focus exclusively on either thermal or mechanical conditions, this research integrates both factors. Material properties such as Young’s modulus, coefficient of thermal expansion, and thermal conductivity vary radially, while Poisson’s ratio is assumed constant.
Using Mathematica, a closed-form analytical solution is developed to derive stress and displacement formulations. This method involves identifying cylinder parameters, specifying constitutive and equilibrium equations, evaluating transient temperature distributions, and applying thermoelastic analysis under defined boundary conditions.The analytical solution for an SS304-Al2O3 FGM model are graphically presented. The investigation delves into the influence of material selection behavior of cylindrical structures where stresses and strains are analyzed in an FGM cylinder made of TZM-SiC under similar boundary conditions. The study further explores the impact of different material indices assumed for the TZM-SiC FGM cylinder, comparing their outcomes. Additionally, it assesses the predominant role of thermal boundary conditions and examines the effects of varying boundary conditions on the TZM-SiC FGM cylinder. These comparative graphical analyses provide insights into optimizing cylindrical structures under transient loading conditions.
The numerical simulations using COMSOL Multiphysics begin with a benchmark study to validate the numerical approach against a previously published study on static internal pressure analysis of FGM structures. Subsequent numerical analysis concentrates on a TZM-SiC FGM thick cylinder subjected to transient radial thermal loading and internal time-dependent pressure. This analysis serves the unique purpose of validating the outcomes reported by the analytical solution.This validation process ensures consistency with analytical outcomes, highlighting the strengths, weaknesses, and accuracies of each method. The discussion of results underscores the significance of the study’s findings in designing and modeling FGM cylinders for applications in nuclear power generation, spacecraft systems, and energy conversion technologies.
The thesis concludes with suggestions for future research, including the impact of multi-axial loading conditions, dynamic and fatigue analysis, experimental validation, thermal shock and creep behavior, environmental and long-term stability, and application-specific studies. These directions aim to enhance the understanding and application of FGMs in advanced engineering fields.