Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Publisher: search.filters.publisher.01. Izmir Institute of TechnologySubject: search.filters.subject.Design optimization

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  • Master Thesis
    Topology Optimization of Non-Linear Elastic Microstructures
    (01. Izmir Institute of Technology, 2023) Özdemir, İzzet; Özdemir, İzzet; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Topology optimization (TO) is used in a broad spectrum of engineering disciplines ranging from aerospace to civil engineering. A particular sub-field where topology optimization has been very instrumental is the design of microstructures that yield specific macroscopic properties, such as negative Poisson's ratio and negative magnetic permeability. In this thesis, based on a recently proposed method for nonlinear homogenization, a framework for topology optimization of nonlinear elastic microstructures is developed and implemented as a computer program using the Julia programming language. Following a plane strain formulation, a two-dimensional unit cell with periodic boundary conditions is used in combination with a neo-Hookean elastic material response. By exploiting the symmetry properties of the resulting orthotropic microstructure, it is shown that the computational domain can be reduced, and half of the original discretization is sufficient to carry out the optimization task. The obtained topologies from the developed computer program, the linear and nonlinear response comparison, and the computational gain achieved through domain reduction are presented along with the experiments on proof-of-concept type uni-axial tests.
  • Master Thesis
    Design Optimization of an Industrial Oven Heat Exchanger
    (01. Izmir Institute of Technology, 2021) Çetkin, Erdal; Çetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The coating application of metals (especially in automotive and white goods sectors) is used in various fields to protect the metal against oxidation, corrosion, scratch, or high temperature to increase product lifetime. The most efficient technique in the coating application is powder coating where the powder is Epoxy-polyester. This process has three steps; surface pretreatment (washing), powder coating, and curing the coated metal. Metals may need to be dried and cured in ovens with 90°C and 200°C, respectively, for the required quality coating process. Burners are used as the heat source in the oven's heat exchangers. Due to high temperatures, the expanding heat exchanger is exposed to various thermal stresses. The stresses cause cracking and rupture problems. The regions where thermal stresses occur intensely are the surfaces with high-temperature differences. Various mass flow rates in the heat exchanger cause non-uniformity for how the energy to be transferred, thus non-uniform surface temperature distribution. In this study, a heat exchanger design provided by "ELECTRON – Sistem Teknik Makina" company has been studied. The mass flow rates in the heat transfer pipes (where the heat is mainly transferred) show deviations up to 75% from the ideal rate. With this study, deviations have been reduced to the level of ±10%. The results show that the maximum thermal stress on the heat exchanger was reduced by 24% with this improvement. In general, the uniform mass flow rates obtained in the heat transfer pipes provided a more homogeneous distribution of the surface temperatures, thus decreased thermal stresses.