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Öğe Investigation of plasma arc cutting parameters with type-2 fuzzy set and system(De Gruyter, 2013-10) Çelik, Yahya Hışman; Özek, Cebeli; Bulut Özek, MüzeyyenThe objective of the present study was it to design a type-2 fuzzy set and system in order to predict surface roughness and hardness depending on the parameters (material thickness, cutting speed, arc voltage and current) of the plasma arc cutting process of S235JR sheet materials. Therefore, some experimental studies were conducted. The experimentally determined data were used to describe the type-2 fuzzy set and system. Type-2 fuzzy set and system was found to be usefull to predict surface roughnes and hardness. According to the obtained values, the best surface roughness and the values closest to the hardness of the raw material were obtained at 1500 mm/min cutting speed, 8 mm material thickness, 115 V arc voltage and 80 A current.Öğe Effects of cutting parameters and point angle on thrust force and delamination in drilling of CFRP(De Gruyter, 2014-11-14) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetParts made of composite materials are generally produced by near-net-shape technology. However, additional machining operations such as drilling are often required to facilitate components assembling. Drilling of composite materials is also a common process in the assembly of aerospace and automotive composite structures. During drilling, unlike the conventional materials, a few damage forms may take place. Among these damage forms, the delamination is the most important one. Therefore, the experimental studies carried out on drilling of CFRP composite materials for determining optimum processing parameters are of great importance. In this particular study, delamination in CFRP composites caused by drilling was investigated. The composite material was drilled under various spindle speeds, feed rates and drill point angles. The results showed that delamination and thrust forces were affected by cutting parameters. It was demonstrated that feed rate and drill point angle make the largest contribution to the overall performance.Öğe Doğal fiber takviyeli kompozitler üzerine bir derleme çalışması(IESS Publishing, 2019-06) Çelik, Yahya Hışman; Yalçın, RojinÖğe Delphi programlama dili kullanılarak plastik enjeksiyon kalıplarında ürün maliyet hesabı ve yeni bir paket programın geliştirilmesi(e-Journal of New World Sciences Academy, 2010-07) Çelik, Yahya Hışman; Özek, Cebeli; Gürgüze, GürkanBu çalışmada, plastik enjeksiyon kalıplama tekniklerini kullanarak kalıplanan plastik ürünlerin maliyet analizini hesaplayan yeni bir program geliştirilmiştir. Geliştirilen maliyet programı için Delphi programlama dili kullanılmıştır. Program, enjeksiyon kalıplama teknikleri ile üretilen bir adet plastik ürünün maliyeti için veri bilgi girişinden seçilen değerlere göre hesaplama yapmaktadır. Elde edilen bilgilere bağlı olarak ham plastik malzeme maliyeti, kalıp maliyetine bağlı amortisman gideri, soket giderleri, işleme ve işçilik giderleri analiz edilerek plastik ürünün tahmini maliyeti hesaplanmaktadır. Programın geçerliliğini kontrol etmek için araçlardaki hava üfleme elemanı örneği seçilmiştir. Programdan elde edilen değerler gerçek değerlerle karşılaştırılarak programın geçerliliği kontrol edilmiştir. Bu verilere bağlı olarak geliştirilen paket program ile gerçek değerler arasında yaklaşık %9,7 kadar bir fark olduğu görülmüştür.Öğe Hardness and wear behaviours of al matrix composites and hybrid composites reinforced with B 4 C and SiC(Springer Nature, 2019-01-15) Çelik, Yahya Hışman; Kılıçkap, ErolThe conversion into the desired shape of the metal powders using Powder Metallurgy (PM) method enables economically mass productions. This case allows producing parts with complex and high dimensional accuracy with no machining. In this study the composites and hybrid composites with Al matrix were produced using PM method with different ratios B4C and SiC. Microhardness and wear experiments of the produced composites were investigated. Wear experiments were performed at a constant speed of 0.5 m/s, application loads of 5, 10 and 15 N and sliding distances of 250, 500, and 750 m. Then, SEM images of composites and hybrid composites were captured. The increase of the reinforcement ratio in the composites contributed to the increase of the hardness. The highest hardness value was computed as 58.7 HV from 16% B4C reinforced composite. In addition, the increase in the reinforcement ratio contributed to the increase of the wear resistance. The increase in the load and sliding distance also increased the wear. The minimum weight loss was calculated as 18 mg from 5 N load, 250 m sliding distance and 16% SiC reinforced composite.Öğe Plastik enjeksiyon kalıplarında enjeksiyon sürelerinin yapay sinir ağları ile modellenmesi(Fırat Üniversitesi, 2011) Çelik, Yahya Hışman; Özek, CebeliÖğe Investigation of turning in different cutting parameters of Al 6061 with finite elements method(Fırat Üniversitesi, 2017-10) Çelik, Yahya Hışman; Özek, Cebeli; Türkan, CihatIn this study, the effects of cutting parameters on cutting force, temperature and stress were investigated in the turning of 6061 aluminum alloy by using DEFORM-3D package program based on finite element method. Constant depth of cut (1 mm), three different cutting speeds (40, 60 and 80 m/min), and three different feed rates (0.05, 0.1 and 0.15 mm/rev) were used in research simulations. From the made analyses, the lowest cutting force was obtained as 150 N at 80 m/min cutting speed and 0.05 mm/rev feed rate, the highest cutting force was obtained as 368 N at 40 m/min cutting speed and 0.15 mm/rev feed rate. While the lowest temperature was obtained as 230 °C at 40 m/min cutting speed and 0.05 mm/rev feed rate, the highest temperature was obtained as 354 °C at 80 m/min cutting speed and 0.05 mm/rev feed rate. In addition, the lowest stress was 997 MPa at 80 m/min cutting speed and 0.05 mm/rev feed rate, the maximum stress was 1090 MPa at 40 m/min cutting speed and 0.15 mm/rev feed rate. It has been observed that the cutting force and the stress value show a similar tendency depending on the cutting parametersÖğe AA5182/AA7075 alüminyum alaşımlarının TIG kaynağında kaynak akımının mekanik özellikler üzerine etkisi(Batman Üniversitesi, 2018) Çelik, Yahya Hışman; Çetkin, Edip; Temiz, ŞemsettinÖğe Investigation of microstructure, hardness values and compressive strengths of SiC/Al composites in different reinforcing rates produced by PM method(Fırat Üniversitesi, 2017-10) Çelik, Yahya Hışman; Kılıçkap, ErolIn this study, the microstructures, hardness values and compressive strength of SiC reinforced Al metal matrix composites in different rates produced by powder metallurgy (PM) method have been examined. Al powders which has 99% purity and 1-210 µm size, and SiC powders which has 98.5% purity and 1-45 µm size were used in experiments. These powders were weighed in proportions pure Al, 4% SiC/Al, 8% SiC/Al, 12% SiC/Al, 16% SiC/Al via precision balance. A mechanical mixing device was used in order to homogeneously mix of the weighed powders. These mixtures were pressed under pressure of 475 MPa. All pressed materials were made into composite by sintering for 120 minutes at 580 ºC. Microstructures, hardness values and compressive strength of the composites were analyzed by polishing the surfaces of the composites. As a result of analysis, it was observed that the SiC reinforces were uniformly dispersed in Al matrix, the hardness values of the composite increased with increasing reinforcement rate and the compressive strength values of the composites were similar to one anotherÖğe Titanyum alaşımlarından Ti-6Al-4V’nın işlenmesinde karşılaşılan zorluklar: Derleme(Gazi Üniversitesi, 2018-01-18) Çelik, Yahya Hışman; Kılıçkap, ErolTitanyum ve alaşımları, mükemmel ısı direnci, korozyon direnci, tokluk, mukavemet, yüksek çalışma sıcaklığı ve düşük ağırlık oranına sahip oldukları için uzay-havacılık, otomotiv, kimyapetrokimya ve biyomedikal gibi çeşitli endüstrilerde yüksek mühendislik alaşımları olarak kullanılmaktadırlar. Ancak bu alaşımlar düşük işlenebilirlik derecelerine sahiptirler. Titanyum ve alaşımlarının işlenmesinde yüzey bütünlüğü ve kesici takım aşınması gibi problemlerle karşılaşılmaktadır. Bu çalışmada, titanyum ve alaşımlarının delinmesinde, frezelenmesinde ve tornalanmasında kesici takım malzemeleri, aşınma mekanizmaları, kesme kuvvetleri, yüzey pürüzlülükleri gibi konular gözden geçirilmiştir. Ayrıca, bu alaşımların işlenmesinde karşılaşılan zorluklar değerlendirilmiş olup yapılmış literatür çalışmaları ayrıntılı olarak ele alınmıştır.
