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Permanent URI for this collectionhttps://acikarsiv.thk.edu.tr/handle/123456789/2552
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Publication Parametric and non-parametric tests for the evaluation of interlaminar fracture toughness of polymer composites(SAGE PUBLICATIONS LTD, 2021) Yavuz, Hande; Utku, Durdu Hakan; Utku, Durdu Hakan; Turkish Aeronautical Association; Turk Hava Kurumu University; Turk Hava Kurumu University; Turkish Aeronautical AssociationThis study is based on the statistical analysis of interlaminar fracture toughness of various laminated polymer composites used in aerospace applications through parametric and non-parametric tests. Tukey's, Dunkan's, two-sample t-test, and Kolmogorov-Smirnov tests are used to analyze tensile mode interlaminar fracture toughness of various fiber-reinforced polymer composites obtained by beam theory, modified beam theory, and modified compliance calibration method. Among the studied composite samples, modified compliance calibration method provided the highest average interlaminar fracture toughness, whereas the modified beam theory showed the lowest one. Room temperature cured carbon fiber-reinforced composite samples exhibited higher interlaminar fracture toughness than the autoclave cured samples. Two-sample t-test show that all methods are found coherent with each other in terms of being significantly different. On the contrary, Kolmogorov-Smirnov test revealed no significant difference. Besides, Tukey's and Duncan's tests exhibited almost the same results in regard to significant differences except those obtained by the modified compliance calibration method. Two-sample t-test method should have to be performed in order to observe significant relations rather than Kolmogorov-Smirnov test, since the results of Tukey's and Duncan's tests are only consistent with each other for the beam theory and modified beam theory method.Publication The hazardous waste location and routing problem: an application in Marmara Region in Turkey(Springer Science and Business Media LLC, 2020-01-30) Durdu Hakan Utku; Serpil Erol; Utku, Durdu HakanPublication A mathematical model on liquefied natural gas supply chain with uncertain demand(Springer Science and Business Media LLC, 2020-08-11) Durdu Hakan Utku; Betül Soyöz; Utku, Durdu HakanPublication Analyzing the Vulnerabilities in a Transshipment Network: A Bilevel Programming Approach(Institute of Electrical and Electronics Engineers (IEEE), 2023) Bayeğ, Selami; Utku, Durdu Hakan; Kasimoğlu, FatihPublication The Evaluation and Improvement of the Production Processes of an Automotive Industry Company via Simulation and Optimization(MDPI AG, 2023-01-27) Durdu Hakan Utku; Utku, Durdu HakanProduction delays are significant problems for the loss of goodwill of the customers and the loss of profits associated with them. The delays may accrue as a result of insufficient resource planning and poorly designed unsatisfactory procedures. In this study, a new mathematical model is proposed to optimize the production processes by minimizing production delays, and a simulation model is developed to test the alternative facility designs. The purpose is to increase customer satisfaction by ensuring that the products are delivered timely and preventing lost sales in an automotive company that manufactures garbage collectors by using real data. The mixed-integer programming problem related to the minimization of production delays is solved by the GAMS CPLEX 24.1.3 software. In this way, the total delay in the production area is minimized by the mathematical model to prevent labor and time loss. Accordingly, the alternative designs are investigated for the improvement of the production processes by using discrete system simulation. A system analysis is performed to determine the bottlenecks in the production processes by developing a simulation model via the ARENA simulation software. With the proposed facility layout alternatives, the delays are eliminated, the total production time is reduced, and an increase in production efficiency is observed.Publication A trapezoidal intuitionistic fuzzy optimization approach for crashing a budget constrained project(Elsevier BV, 2024-04) Fatih Kasimoglu; Selami Bayeg; Adem Pinar; Durdu Hakan Utku; Utku, Durdu Hakan; Utku, Durdu Hakan