Filtreler

2018 - 201912020 - 20211
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Ayarlar

Bölüm: Işık University, Faculty of Engineering, Department of Mechanical Engineering × Konu: Coatings ×

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Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Yayın
    Coordination in building an observatory: A case study of Eastern Anatolian Observatory (DAG)
    (SPIE-Int Soc Optical Engineering, 2018) Şahmalı, Ali Erkan; Yeşilyaprak, Cahit; Keskin, Onur
    Eastern Anatolian Observatory (DAG) is designed to build on one of the summits of Palandoken Mountains in Erzurum, Turkey, at an altitude of 3,151 meters. The building is under construction since 2015 and expected to be completed in 2020. The building is designed as an integrated building, having operational departments, services, mechanical and electrical infrastructure for observations as well as cleaning and coating units, adjacent to the main observatory building. As one might expect this integration creates serious coordination problems between architect, engineers, telescope, enclosure, and cleaning & coating unit manufacturers. The construction progress of the investment is almost 20%. There are quite an amount of "lessons learned" in this period, and need to be developed by the parties, for their existing and future works. The building has so many challenges such as geological and geographical limitations, environmental and meteorological constraints, engineering and structural considerations, energy efficiency and sustainability, materials used and their performances at these limitations.
  • Küçük Resim
    Yayın
    Transient multi-domain thermal modeling of interrupted cutting with coated tools
    (Springer Science and Business Media Deutschland GmbH, 2021-09) Karagüzel, Umut
    Interrupted cutting operations, such as milling, produce fluctuating tool temperatures which directly affect the process outputs. Thus, prediction of cutting tool temperatures enables process planning, selection of materials for tool substrate and coating layers, and tool geometric design for improved productivity in machining operations. Theoretical analysis of temperature is a cost effective way to predict the tool temperatures. Considering the industrial needs, a theoretical model should be fast, easy to implement, and reliable. To that end, a novel hybrid model, which assembles analytical and numerical methods, is proposed in this study. This novel transient thermal model simulates the interrupted cutting with coated cutting tools. The proposed model includes an analytical heat flux calculation at the tool-chip interface considering the sticking-sliding contact behavior. The determined heat flux is, then, used to perform a numerical solution of the transient heat conduction problem in the cutting tool geometry with temperature-dependent thermal properties. The developed model is validated with experimental results found in literature under different cutting conditions. The results show that the model can predict the maximum temperatures generated in a thermal cycle with an accuracy of 2–10%. Thus, the proposed model can be further used to determine the process parameters, properties of coating layers, and tool geometric design.