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Öğe Grafen nanopartikül takviyeli epoksi kompozitlerin aşınma davranışı(Dicle Üniversitesi, 2018-11) Çelik, Yahya Hışman; Topkaya, TolgaNanoboyutlu dolgu maddeleri, nanotakviyeli kompozitlerin mekanik, termal ve elektriksel özelliklerini iyileştirir. Mevcut çalışmada grafen (G) nanopartikül takviyeli epoksi kompozitlerin aşınma davranışı pin on disk cihazı kullanılarak araştırılmıştır. Bu doğrultuda, takviyesiz epoksi ile %0.1, %0.2, %0.3, %0.4 ve %0.5 oranında G nanopartikül içeren epoksi kompozitler üretilmiştir. Üretilen kompozitlerin adhesiv aşınma deneyleri gerçekleştirilmiştir. Adhesiv aşınma deneylerinde, yük, kayma hızı ve kayma mesafesi sırasıyla 10 N, 0.35 m/s ve 250 m seçilmiştir. Ayrıca aşındırıcı olarak 5 mm çapa sahip paslanmaz çelik bilye kullanılmıştır. Sonuçlar artan takviye oranının numunelerin aşınma mukavemetini arttırdığını göstermiştir. Nanoboyutlu dolgu maddeleri, nanotakviyeli kompozitlerin mekanik, termal ve elektriksel özelliklerini iyileştirir. Mevcut çalışmada grafen (G) nanopartikül takviyeli epoksi kompozitlerin aşınma davranışı pin on disk cihazı kullanılarak araştırılmıştır. Bu doğrultuda, takviyesiz epoksi ile %0.1, %0.2, %0.3, %0.4 ve %0.5 oranında G nanopartikül içeren epoksi kompozitler üretilmiştir. Üretilen kompozitlerin adhesiv aşınma deneyleri gerçekleştirilmiştir. Adhesiv aşınma deneylerinde, yük, kayma hızı ve kayma mesafesi sırasıyla 10 N, 0.35 m/s ve 250 m seçilmiştir. Ayrıca aşındırıcı olarak 5 mm çapa sahip paslanmaz çelik bilye kullanılmıştır. Sonuçlar artan takviye oranının numunelerin aşınma mukavemetini arttırdığını göstermiştir.Öğe Mechanical properties of fiber/graphene epoxy hybrid composites(SpringerLink, 2020-11-18) Çelik, Yahya Hışman; Topkaya, Tolga; Kılıçkap, ErolThe aim of this study is to determine the effect of graphene nanoparticle (GNP) reinforcement on the mechanical properties of glass fiber reinforced polymer (GFRP), carbon fiber reinforced polymer (CFRP) and aramid fiber reinforced polymer (AFRP) composites commonly used in the space and defense industry. Accordingly, GFRP, CFRP and AFRP composites were produced by using hot pressing method. In addition, hybrid fiber composites were produced by adding 0.1 %, 0.2 % and 0.3 % GNP to these fiber reinforced composites. The tensile strength and modulus of elasticity of the composites were determined. The tensile damage fracture regions were analyzed by scanning electron microscopy (SEM) and energy distribution spectrum (EDS). It was observed that the addition of 0.2 wt. % GNP to GFRP and CFRP composites increased tensile strength and modulus of elasticity. However, the addition of 0.2 wt. % GNP to AFRP composites had no effect on the tensile strength; on the contrary, it partially reduced the tensile strength but increased the modulus of elasticity. On the fracture damage surfaces of the GFRP and CFRP composites and the GNP/GFRP and GNP/CFRP hybrid composites, the fibers were completely separated. On the damage surfaces of AFRP composite and GNP/AFRP hybrid composites, the fibers were deformed but these fibers were not separated from each other. From the EDS analysis, it was observed that the element C increased in the composites with the addition of GNP to the fiber reinforced compositesÖğe Evaluation of drilling performances of nanocomposites reinforced with graphene and graphene oxide(Springer Nature, 2018-09-16) Çelik, Yahya Hışman; Kılıçkap, Erol; Koçyiğit, NihayetThe use of graphene (G) and graphene oxide (GO) reinforced nanocomposites have a great importance since G and GO improve the interface conditions of composite materials. However, the effects of G and GO on some mechanical properties and machinability in nanocomposites are still a research topic. In this study, G was converted to GO by Hummers’ method. G and GO nanoparticles were added to epoxy at different ratios and the tensile strengths of nanocomposites were determined. By taking into account, the reinforcement ratio of nanocomposites having the highest tensile strength, epoxy with G and GO, and unreinforced epoxy were added to carbon fiber (CF) fabric by hand lay-up. Thus, fabrication of the carbon fiber-reinforced plastic (CFRP) composite, and the G/CFRP and GO/CFRP nanocomposites was carried out. The effects of the G and GO on the fabricated nanocomposites, and the effect of different drilling parameters (cutting speed and feed rate) on the cutting force, cutting torque, temperature, and delamination factor were investigated. In the drilling of these composites, drills with the different bit point angles and the diameter of 5 mm were used. As a result, it was observed that GO was successfully synthesized, and G and GO positively affected the tensile strength, and GO exhibited a more effective feature than G on the tensile strength. It was also seen that the increase of the cutting speed, feed rate, bit point angle caused the increase in the cutting forces, cutting torque, and delaminations.Öğe Evaluation of drilling performances of nanocomposites reinforced with graphene and graphene oxide(Springer Nature, 2019-02-25) Çelik, Yahya Hışman; Kılıçkap, Erol; Koçyiğit, NihayetThe use of graphene (G) and graphene oxide (GO) reinforced nanocomposites have a great importance since G and GO improve the interface conditions of composite materials. However, the effects of G and GO on some mechanical properties and machinability in nanocomposites are still a research topic. In this study, G was converted to GO by Hummers’ method. G and GO nanoparticles were added to epoxy at different ratios and the tensile strengths of nanocomposites were determined. By taking into account, the reinforcement ratio of nanocomposites having the highest tensile strength, epoxy with G and GO, and unreinforced epoxy were added to carbon fiber (CF) fabric by hand lay-up. Thus, fabrication of the carbon fiber-reinforced plastic (CFRP) composite, and the G/CFRP and GO/CFRP nanocomposites was carried out. The effects of the G and GO on the fabricated nanocomposites, and the effect of different drilling parameters (cutting speed and feed rate) on the cutting force, cutting torque, temperature, and delamination factor were investigated. In the drilling of these composites, drills with the different bit point angles and the diameter of 5 mm were used. As a result, it was observed that GO was successfully synthesized, and G and GO positively affected the tensile strength, and GO exhibited a more effective feature than G on the tensile strength. It was also seen that the increase of the cutting speed, feed rate, bit point angle caused the increase in the cutting forces, cutting torque, and delaminations.
