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Öğe Investigation of mechanical properties of composites obtained from textile wastes(Batman Üniversitesi, 2022-07-02) Adin, Mehmet ŞükrüThe textile industry is one of the manufacturing sectors that pollutes the world the most. Since textile wastes are destroyed by burning traditionally, they cause great damage to the environment. Therefore, recycling of these wastes is of great importance. One of these recycling methods is their use in the production of composite materials, the application areas of which have increased in recent years. In this study, the mechanical properties of composite materials produced using cotton and polyester fabrics from waste textiles were investigated. It has been observed that 22% of the composite materials produced with reinforcement elements at different angles (0°, 45°, 90°) are reinforcement elements and 78% are resins. As a result of the tensile tests, the highest tensile strength value was obtained with the polyester fabric with 0° reinforcement angle as 55.72 MPa. It has been found that the increase in the reinforcement angles positively affects the tensile strength in cotton fabric reinforced composites, whereas this situation occurs in the opposite way in polyester fabric reinforced composites. When the highest tensile strength values of polyester fabric and cotton fabric reinforced composite samples were compared, it was seen that the sample using polyester fabric (55.72 MPa) had 69% higher tensile strength than the sample using cotton fabric (33.05 MPa). In addition, the elongation values of polyester fabric reinforced composites were higher than cotton fabric reinforced composites.Öğe Effect of welding parameters on microstructure and mechanical properties of AA7075/AA5182 alloys joined by TIG and MIG welding methods(SpringerLink, 2020) Çelik, Yahya Hışman; Temiz, Şemsettin; Çetkin, EdipIn this study, V and X welding grooves were opened to the forehead positions of the AA5182 and AA7075 aluminum alloy pairs and these alloy pairs were joined with tungsten inert gas (TIG) and metal inert gas (MIG) methods. Three diferent welding currents were used in joints. Gas fow rates of 12 and 17 l/min at the TIG welding and wire feed rates of 38 and 45 cm/min at MIG welding were selected. The efect of the welding grooves, welding current, gas fow rate and wire feed rate on microstructure and mechanical properties were investigated. Microstructures of welding zones were analyzed by an optical microscope and a scanning electron microscope (SEM). Vickers hardness of these zones was also measured. In addition, tensile and fatigue tests were carried out. Fracture mechanisms of failed specimens were conducted after the tensile tests were examined by using SEM. The highest hardness, tensile and fatigue strengths were obtained from the alloy pairs joined by opening X welding groove with TIG welding method. These values were 89 HV, 262.87 MPa, and 131.5 MPa, respectively. Similarly, the lowest tensile and fatigue strengths were obtained from the alloy pairs joined by opening V welding groove in the TIG welding method. These values were, respectively, 94.48 MPa and 19.1 MPa. However, the minimum hardness value was measured as 58 HV from the alloy pairs joined by opening V welding groove with MIG welding methods. In addition, it was observed on the fracture surfaces that the grain distributions and mechanisms difered depending on the welding methods, welding groove, and welding parameters.Öğe Investigation of optimal MIG welding parameters and energy consumption for Invar alloys(Batman Üniversitesi, 2022-07-02) Adin, Mehmet ŞükrüInvar alloys are materials used in aviation and aerospace industries to make precision components and test equipment due to their excellent coefficient of thermal expansion. Therefore, the diversity of the joining methods of these materials and their joint strength have gained importance. In the presented study, the optimum welding parameters required for the minimum use of energy consumed during MIG welding of Invar alloy materials and for the joints to have the highest tensile strength were investigated. The lowest tensile strength was found to be 375 MPa at 15 mm/s welding speed and 6 mm/s wire feeding speed, and the highest tensile strength was 405 MPa at 20 mm/s welding speed and 18 mm/s wire feed. It has been understood that the power consumed for joining Invar alloy bars generally increases in direct proportion to the parameter increases up to 20 mm/s welding speed. It was observed that the lowest consumed power value was 1.61 kW with 15 mm/s welding speed and 6 mm/s wire feeding speed, while the highest consumed power value was 3.93 kW with 25mm/s welding speed and 18 mm/s wire feeding speed. It has been understood that an average of 38% energy savings can be achieved thanks to the optimum parameters obtained.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 The effect of drilling parametrers on stregth of glass fibre-epoxy laminates by produced hand lay-up(e-Journal of New World Sciences Academy, 2017-10-22) Çelik, Yahya Hışman; Kılıçkap, Erol; Yenigün, BurakIn this study, the effects of delamination factor on strength of glass fiber reinforced plastic (GFRP) composite with +45/-45 orientation angle fabrics were investigated. GFRP composite specimens, which contain 36% fiber volume, were produced by hand lay-up. The all specimens were prepared according to ASTM D5766-2002 standards. The experiments were conducted the different drilling parameters such as cutting speeds and feed rates using tungsten carbide (WC) and Brad Spur drill tools. Delamination factors of drilled specimens were determined by optical microscope. The tensile strength values of the drilled GFRP composite specimens were determined by universal tensile testing machine. As results, it was determined that the increasing cutting speed and feed rate increased the delamination factor. The strength of GFRP composites decreased with increasing delamination factor.Öğe Investigation of mechanical characteristics of GFRP composites produced from chopped glass fber and application of taguchi methods to turning operations(SpringerLink, 2020-04-08) Çelik, Yahya Hışman; Türkan, CihatGlass fber-reinforced plastic (GFRP) composites take place in engineering materials owing to their low-weight and high-mechanical properties. In some cases, they need to be shaped by machining before using in industrial applications. However, when these composites are machined, many problems such as bad surface quality, rapid tool wear are encountered. Therefore, optimization of cutting parameters is essential to eliminate or minimize these problems. In this study, GFRP composites were produced by combining polyester matrix material with glass fbers (GF) having 6 mm, 6–12 mm, 12 mm fber length, and 20%, 25%, 30% fber ratio by weight. The tensile strengths of these composites were investigated. Turning tests were also performed with cutting speeds of 40, 80, and 120 m/min, feed rates of 0.1, 0.2 and 0.3 mm/rev, and depth of cut of 1, 2, and 3 mm, according to Taguchi L27 standard orthogonal array method. The efect of fber length and ratio, and cutting parameters on cutting forces and surface roughness were analyzed. As a result of the experiments, it was observed that the reinforced polymer matrix with GF provide to increase the tensile strength. The highest tensile strength was obtained as 55.95 MPa from the composite having a fber length of 12 mm and a fber ratio of 25%. Besides, the feed rate was determined as the most efective parameter among the all parameters on both cutting force and surface roughness. Therefore, the feed rate should be chosen low for lower cutting force and surface roughness values.Öğe Microstructure and mechanical properties of AA7075/AA5182 jointed by FSW(Journals & Books, 2019-06) Çelik, Yahya Hışman; Çetkin, Edip; Temiz, ŞemsettinIn this study, AA7075 and AA5182 aluminium alloys were joined using different rotation speeds (980, 1325 and 1800 rpm), feed rates (108 and 233 mm/min) and stirred pins having two different geometries (conical helical and triangular). Microstructures of welding joints were examined by an optical microscope and a scanning electron microscope (SEM). Vickers hardness measurements were performed in the welding zone of samples removed from each welded plate. Tensile and fatigue tests were also applied to the test specimens taken from the welded plates. After the tensile tests, the surface fractures and possible welding defects were scanned via SEM. The best mechanical properties were obtained when conical helical shape stirrer pins were used. The values were 265 MPa for tensile test and 159 MPa for fatigue test. The hardness value was very close to each other and varied depending on the rotation speed. The highest hardness value was determined as 87 HV in the weld center at 1325-rpm rotation speed.Öğe Optimization of mechanical properties of composites obtained from textile wastes using Taguchi and ANOVA methods(Batman Üniversitesi, 2022-07-02) Adin, Mehmet ŞükrüToday, one of the most polluting manufacturing sectors is the textile industry. Therefore, recycling of these wastes is of great interest. One of the solutions applied for the recycling of these wastes is their use in the manufacture of composites. In this study, optimization of manufacturing parameters was made in order to obtain plates with the highest tensile strength from composite materials to be produced from textile wastes by using Taguchi and ANOVA methods. As a result of the study, it was found that the tensile strength of the composite plates made of polyester fabric was higher than the plates made of cotton fabric, and the signal/noise (S/N) ratios of 0° angle reinforced composites were lower than 90° angle reinforced composites. It was observed that there was a nearly linear increase in the S/N ratios depending on the increase in the number of reinforcements. As a result of the ANOVA analysis, it was found that the most effective factor according to the tensile strength was the reinforcement angle with 45.06%. It was observed that the highest tensile strength of the composite plates obtained from cotton fabric was 40.058 MPa with 90° angled reinforcement elements and 14 reinforcements, and the lowest tensile strength was 23.451 MPa with 0° angled reinforcement elements and 10 reinforcements. In composite plates obtained from polyester fabric, the highest tensile strength was 42.136 MPa with 45° angled reinforcement elements and 14 reinforcements, and the lowest tensile strength was 27.112 MPa with 0° angled reinforcement elements and 10 reinforcement numbers. It has been found that the tensile strength of the composite plates obtained from polyester fabric is higher than that of the composite plates obtained from cotton fabric.
