Person: BİLİCİ, MUSTAFA KEMAL
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BİLİCİ
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MUSTAFA KEMAL
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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 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 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 Effects of welding parameters on friction stir spot welding of high density polyethylene sheets(ELSEVIER SCI LTD, 2012) BİLİCİ, MUSTAFA KEMAL; Bilici, Mustafa Kemal; Yukler, Ahmet IrfanFriction stir spot welding parameters affect the weld strength of thermoplastics, such as high density polyethylene (HOPE) sheets. The effects of the welding parameters on static strength of friction stir spot welds of high density polyethylene sheets were investigated. For maximizing the weld strength, the selection of welding parameters is very important. In lap-shear tests two fracture modes were observed; cross nugget failure and pull nugget failure. The tool rotational speed, tool plunge depth and dwell time were determined to be important in the joint formation and its strength. The joint which had a better strength fails with a pull nugget failure morphology. Weld cross section image analysis of the joints were done with a video spectral comparator. The plunge rate of the tool was determined to have a negligible effect on friction stir spot welding. (C) 2011 Elsevier Ltd. All rights reserved.Publication Metadata only Application of Taguchi approach to optimize of FSSW parameters on joint properties of dissimilar AA2024-T3 and AA5754-H22 aluminum alloys(ELSEVIER SCI LTD, 2013) BİLİCİ, MUSTAFA KEMAL; Bozkurt, Yahya; Bilici, Mustafa KemalIn this study, the effect of plate positioning on mechanical properties of dissimilar lap joints was investigated by friction stir spot welding (FSSW) process. The determination of the welding parameters plays an important role for the weld strength. For the effective use of the dissimilar aluminum joints, the FSSW must have an adequate strength. The quality of the joint was evaluated by examining the characteristics of the joining efficiency as a result of the lap-shear tensile test. Four process parameters were selected: the tool rotation speed, dwell time, tool plunge depth, and tilt angle. The process parameters were optimized by Taguchi technique based on Taguchi's L9 orthogonal array. The optimum welding process parameters were predicted, and their percentage of contribution was estimated by applying the signal-to-noise ratio and analysis of variance. The experimental results showed that the positioning of the plates played an important role on the strength of the joints. Finally, the results were confirmed by further experiments. Crown Copyright (c) 2013 Published by Elsevier Ltd. All rights reserved.Publication Metadata only Influence of tool geometry and process parameters on macrostructure and static strength in friction stir spot welded polyethylene sheets(2012) BİLİCİ, MUSTAFA KEMAL; Bilici M.K., Yükler A.I.The effect of important welding parameters and tool properties that are effective on static strength in friction stir spot welds of polyethylene sheets were studied. Six different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular, square and hexagonal) with different shoulder geometries, different pin length, pin angle and concavity angle were used to fabricate the joints. The tool rotational speed, tool plunge depth and dwell time were determined welding parameters. All the welding operations were done at the room temperature. Welding force and welding zone material temperature measurements were also done. Lap-shear tests were carried out to find the weld static strength. Weld cross section appearance observations were also done. From the experiments, the effect of pin profile, pin length, pin angle, dwell time and tool rotational speed on friction stir spot welding formation and weld strength was determined. © 2011 Elsevier Ltd.