Person: BİLİCİ, MUSTAFA KEMAL
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BİLİCİ
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MUSTAFA KEMAL
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Publication Metadata only İş sağlığı ve güvenli̇ği çalişmalarının çalışanların performans ve veri̇mli̇li̇kleri̇ne etki̇ eden faktörleri̇n araştırılması(Gazi Kitabevi, 2022-01-01) BİLİCİ, MUSTAFA KEMAL; BİLİCİ M. K.Publication Metadata only Investigation of friction stir spot welding of high density polyethylene and polypropylene sheets(SAGE PUBLICATIONS LTD, 2021) BİLİCİ, MUSTAFA KEMAL; Bilici, Mustafa KemalIn this study, two different polymer materials were used. In the joints made with friction stir spot welding, firstly (PP/PP and HDPE/HDPE) and then different materials (PP/HDPE, HDPE/PP) joining processes were carried. The influence of the tool rotational speed and the stirring time on joint formation and weld strength were determined. The temperature of the liquid welding materials varies according to the materials to be combined. High weld strengths were obtained at the friction stir spot welding of similar plastic sheets. The highest weld strengths were obtained in PP-PP welds. Low weld strengths were obtained at the friction stir spot welding of dissimilar plastic sheets because of immiscible and incompatible blends formed during the welding operation. The lowest weld strengths were obtained in PP-HDPE welds. The chemical composition and the phase morphology of the blends, the mechanical scission occurrence and the welding residual stresses determine the strength of the welds.Publication Metadata only Application of Taguchi approach to optimize friction stir spot welding parameters of polypropylene(ELSEVIER SCI LTD, 2012) BİLİCİ, MUSTAFA KEMAL; Bilici, Mustafa KemalThis paper shows experimental and numerical results of friction stir spot welding of high density polypropylene. The determination of the welding parameters plays an important role for the weld strength. The experimental tests, conducted according to combinations of process factors such as tool rotation speed, plunge depth and dwell time at beginning welding, were carried out according the Taguchi orthogonal table L9 in randomized way. The Taguchi approach was used as a statistical design of experiment technique to set the optimal welding parameters. The results show coherence between the numerical predictions and experimental observations in different cases of weld strength. The signal-to-noise ratio and the analysis of variance were utilized to obtain the influence of the friction stir spot welding parameters on the weld strength. Finally, the improvement in the weld strength from the initial welding parameters to the optimal welding parameters was about 47.7%. (C) 2011 Elsevier Ltd. All rights reserved.Publication Metadata only The optimization of welding parameters for friction stir spot welding of high density polyethylene sheets(ELSEVIER SCI LTD, 2011) KURTULMUŞ, MEMDUH; Bilici, Mustafa Kernal; Yukler, Ahmet Irfan; Kurtulmus, MemduhFriction stir spot welding parameters affect the weld strength of thermoplastics, such as high density polyethylene (HDPE) sheets. The strength of a friction stir spot weld is usually determined by a lap-shear test. For maximizing the weld strength, the selection of welding parameters is very important. This paper presents an application of Taguchi method to friction stir spot welding strength of HOPE sheets. An orthogonal array, the signal to noise ratio (S/N), and the analysis of variance (ANOVA) are employed to /investigate friction stir welding parameter effects on the weld strength. From the ANOVA and the S/N ratio response graphs, the significant parameters and the optimal combination level of welding parameters were obtained. Experimental results confirmed the effectiveness of the method. (C) 2011 Elsevier Ltd. All rights reserved.Publication Metadata only Investigation of the effects of welding variables on the welding defects of the friction stir welded high density polyethylene sheets(SAGE PUBLICATIONS LTD) BİLİCİ, MUSTAFA KEMAL; Bilici, Mustafa KemalModern thermoplastic materials are used in an expanding range of engineering applications, such as in the automotive industry, due to their enhanced stress-to-weight ratios, toughness, a very short time of solidification, and a low thermal conductivity. Recently, friction stir welding has started to be used in joining processes in these areas. There are many factors that affect weld performance and weld quality in friction stir welding (FSW). These factors must be compatible with each other. Due to the large number of welding variables in friction stir welding processes, it is very difficult to achieve high strength FSW joints, high welding performance, and control the welding process. Welding variables that form the basis of friction stir welding; machine parameters, tool variables, and material properties are divided into three main groups. Each welding variable has different effects on the weld joint. In this study, friction stir welds were made on high density polyethylene (HDPE) sheets with factors selected from machine parameters and welding tool variables. Although the welding performance, quality, and strength gave good results in some conditions, successful joints could not be realized in some conditions. In particular, welding defects occurring in the combination of HDPE material with FSW were investigated. Welding quality, defects, and performances were examined with macrostructure. In addition, the tensile strength values of some the joints were determined. The main purpose of this study is to determine the welding defects that occur at the joints. The causes of welding defects, prevention methods, and which weld variables caused were investigated. Welding parameters and welding defects caused by welding tools were examined in detail. In addition, the factors causing welding defects were changed in a wide range and the changes in the defects were observed.Publication Open Access Effect of tool geometry on friction stir spot welding of polypropylene sheets(BUDAPEST UNIV TECHNOL & ECON, 2012) BİLİCİ, MUSTAFA KEMAL; Bilici, M. K.The effects of tool geometry and properties on friction stir spot welding properties of polypropylene sheets were studied. Four different tool pin geometries, with varying pin angles, pin lengths, shoulder diameters and shoulder angles were used for friction stir spot welding. All the welding operations were done at the room temperature. Lap-shear tensile tests were carried out to find the weld static strength. Weld cross section appearance observations were also done. From the experiments the effect of tool geometry on friction stir spot weld formation and weld strength were determined. The optimum tool geometry for 4 mm thick polypropylene sheets were determined. The tapered cylindrical pin gave the biggest and the straight cylindrical pin gave the lowest lap-shear fracture load.Publication Metadata only Effect of welding parameters on mechanical properties and microstructure of friction stir welded brass joints(EDP SCIENCES S A, 2019) BİLİCİ, MUSTAFA KEMAL; Gecmen, Inan; Catalgol, Zarif; Bilici, Mustafa KemalFriction stir welding is a method developed for the welding of high-alloy aluminum materials which are difficult to combine with conventional welding methods. Friction stir welding of MS 63 (brass) plates used different tools (tapered cylindrical, tapered threaded cylindrical), tool rotational speeds (1040, 1500, 2080 rpm) and traverse speeds (30,45,75,113 mm.min(-1)). Tensile, bending, radiography and microstructure tests were carried out to determine the mechanical properties of brass plates joined by friction stir welding technique. Microstructure characterization studies were based on optical microscope and SEM analysis techniques. In addition, after joining operations, radiographs were taken to see the internal structure failure. Brass sheets were successfully joined to the forehead in the macrostructure study. In the evaluation of the microstructure, it was determined that there were four regions of base metal, thermomechanically affected zone (TMEB), heat-affected zone (HAZ) and stir zone. In both welding tools, the weld strength increased with increasing tool rotation speed. The particles in the stir zone are reduced by increasing of the tool rotation speed. Given the strength and % elongation values, the highest weld strength was achieved with tapered pin tool with a tool rotation speed of 1040 rpm and a tool feed speed of 113 min(-1).Publication Open Access Investigation of Factors Affecting Friction Stir Welding of Polyethylene by ANOVA Analysis(KAUNAS UNIV TECH, 2021-08-23) BİLİCİ, MUSTAFA KEMAL; Bilici, Mustafa Kemal; Yukler, Ahmet Irfan; Kurtulmus, Memduh; Kartal, IlyasThe variables that are effective in joining high density polyethylene sheets by friction stir welding (FSW) have been investigated. In order to understand the effects of welding parameters, using Taguchi optimization, tool rotation speed, feed rate, shoulder diameter and pin diameter values were selected in a wide range. The results obtained with Taguchi optimization method were evaluated according to the highest / the best signal-noise ratio. Macro photographs taken crosssectional view taken the weld seam, SEM images and hardness measurements were used to evaluate. As a result of the evaluation, the accuracy of the optimization was found to be approximately 96 %. As a result, feed rate and shoulder diameter were determined as the most effective parameter affecting the welding quality and welding performance. These two parameters (shoulder diameter and feed rate) have found to effect of approximately 65 % on tensile strength, weld quality and hardness. Finally, it has obtained that the most effective welding parameter was the shoulder diameter with 40.81 %.Publication Open Access Investigation of wear behavior of Ti-6Al-4V/CNT composites reinforced with carbon nanotubes(GAZI UNIV, FAC ENGINEERING ARCHITECTURE, 2018-09-12) GÜLLÜOĞLU, ARİF NİHAT; Topcu, Ismail; Gulluoglu, Arif N.; Bilici, M. Kemal; Gulsoy, H. OzkanIn this study, the effects of different production conditions and different sintering conditions on microstructure, density and wear resistance of Multi-wall carbon nanotubes (CNTs) powders reinforced with Titanium (Ti-6Al-4V) powder by mechanical alloying were examined. The powders produced by mechanical alloying were compressed with a Cold Isostatic Press die under a pressure of 250 MPa in this molding machine to obtain cylindrical composite specimens. These raw specimens were extruded at 1275 degrees C for 60 minutes in a high purity argon atmosphere and high vacuum (1.2 10-5 mbar). The erosive wear behavior of the Ti-6Al-4V / CNTs metal matrix composite was studied using a pin-on-disc wear tester. The abrasion behavior of a Ti-6Al-4V / CNTs alloy after various heat treatments has been studied on abrasive wear. Under appropriate conditions it has been shown that reinforced CNTs can reduce the wear rate by more than two orders of magnitude. Various investigations have been carried out detailing the reinforcement rates of this improved wear performance. The friction and wear data show a clear surplus value added to the composite Ti-6Al-4V wear modes. As a result, in the experimental studies made, it is seen that the wear resistance increase according to the v/v % CNTs ratio which is directly supplemented to the volume. However, this properties had been decrease with the % 5 CNTs ratio.Publication Metadata only Additive manufacturing in formula one (F1) cars: A review on processes, applications(2023-12-01) BİLİCİ, MUSTAFA KEMAL; BİLİCİ M. K.t Additive manufacturing (AM) technology has been developing rapidly in recent years and its use in different sectors is increasing day by day. The working system of AM technology, unlike traditional production methods, is a layer-based production process by creating layers on top of each other. Due to its advantages such as material savings, low cost, production of parts without the need for molds and design flexibility, especially in complex shaped parts, it has found use in many fields, especially in medical, aviation and automotive. The biggest disadvantage of the AM method is that parts of a certain size can be produced due to the size of the part to be produced. To eliminate this problem in AM technology, it is possible to create large parts by combining small parts. In this research study, the role and development of additive manufacturing in the production and development of Formula One (F1) cars, which is the leading world championship in motor sports, which parts are produced with this method and why, in a system based on continuous improvement, A.M. on what advantages it provides. Examples are given on the parts produced by additive manufacturing in Formula 1 vehicles, and the advantages of being produced with additive manufacturing are explained with sample photographs.