Kaftanoğlu, Bilgin
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Name Variants
Bilgin, Kaftanoğlu
Kaftanoglu, Bilgin
Bilgin Kaftanoğlu
K., Bilgin
Kaftanoğlu,B.
Kaftanoğlu, Bilgin
K.,Bilgin
B.,Kaftanoglu
KAFTANOGLU B.
Kaftanoğlu B.
B.,Kaftanoğlu
Kaftanoglu,B.
Bilgin, Kaftanoglu
Kaftanoglu B.
Kaftanoglu,Bilgin
B., Kaftanoğlu
B., Kaftanoglu
Kaftanoglu, B.
Kaftanoglu, Bilgin
Bilgin Kaftanoğlu
K., Bilgin
Kaftanoğlu,B.
Kaftanoğlu, Bilgin
K.,Bilgin
B.,Kaftanoglu
KAFTANOGLU B.
Kaftanoğlu B.
B.,Kaftanoğlu
Kaftanoglu,B.
Bilgin, Kaftanoglu
Kaftanoglu B.
Kaftanoglu,Bilgin
B., Kaftanoğlu
B., Kaftanoglu
Kaftanoglu, B.
Job Title
Profesör Doktor
Email Address
bilgin.kaftanoglu@atilim.edu.tr
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
44
Articles
23
Citation Count
695
Supervised Theses
12
44 results
Scholarly Output Search Results
Now showing 1 - 10 of 44
Article Citation Count: 59A mechanistic approach to investigate drilling of UD-CFRP laminates with PCD drills(Elsevier, 2014) Karpat, Y.; Bahtiyar, O.; Deger, B.; Kaftanoglu, Bilgin; Manufacturing EngineeringCarbon fiber reinforced plastics (CFRPs) possess desirable material properties that satisfy the aerospace industry's high strength to weight ratio objective. Therefore, CFRPs are commonly used in structural parts, either alone or together with aluminum and titanium alloys. Drilling of CFRPs has been studied extensively in the literature in recent years, with special emphasis on process parameters and delamination. This study identifies mechanical properties of uni-directional CFRPs through drilling tests. Drilling of uni-directional CFRP plates with and without pilot holes has been performed, and cutting and edge force coefficients are identified. A polycrystalline diamond (PCD) drill was used in tests since this type of drill is commonly used in practice. Finally, validation tests on multi directional CFRP laminates have been performed and good results have been obtained. (C) 2014 CIRP.Article Citation Count: 0Design and Manufacturing of a Pin on Disk Tribometer(2024) Küçüköztaş, Korcan; Nassar, Mohammed; Kaftanoğlu, Bilgin; Talay, İlker; Manufacturing EngineeringThis paper presents the design and manufacturing of a pin on disk tribometer aimed at performing friction and wear testing as accurate as a professional tribometer at a lower cost. Since friction is an important part of our lives and its application varies greatly in size, environment and other factors, testing can be expensive. Tribometers are instruments where these conditions can be simulated experimentally. They are manufactured by various companies abroad and are imported to Turkey. For this reason, the cost of these instruments is very high. The design of the manufactured tribometer prioritizes portability and low cost of manufacturing. The manufacturing process of the various parts are discussed in detail. The tribometer was manufactured in the ATILIM University manufacturing laboratories within a tight budget using CNC machining. The instrument has the full capability to adjust the load, testing radius, motor speed, and the duration of the test before starting the experiments. To handle the electronics and data gathering within the instrument, Arduino boards and software are utilized. Real-time data streaming is made possible for data analysis tasks both during and after the experiments. The paper also provides the results of experiments that are obtained from the newly developed tribometer and comparisons with a mass produced, professional tribometer. The experiments are conducted with the same type of samples and with the same parameters. The manufactured tribometer provides researchers with easily accessible friction data that is within close range to what they would get from a professional tribometer.Article Citation Count: 12Coating of titanium implants with boron nitride by RF-magnetron sputtering(indian Acad Sciences, 2016) Gokmenoglu, Ceren; Ozmeric, Nurdan; Cakal, Gaye; Dokmetas, Nihan; Ergene, Cansu; Kaftanoglu, Bilgin; Manufacturing EngineeringSurface modification is necessary for titanium implants since it is unable to induce bone apposition. The beneficial effects of boron on bone formation, composition and physical properties make it suitable as a coating material. In the present study, surface properties of boron nitride (BN) coating on titanium implants were evaluated. Twenty-four implants and 12 abutments were coated with BN by RF-magnetron sputtering system. ATR-FTIR measurements were conducted to assess surface chemistry and morphology of BN-coated implants. Adhesion tests were performed by CSM nanoscratch test device to determine adhesion of BN to titanium surface. Surface profilometry and atomic force microscopy (AFM) was used to evaluate surface roughness. Mean roughness values were calculated. Contact angle measurements were done for evaluation of wettability. Surface characterization of coated implants was repeated after RF power of the system was increased and voltage values were changed to evaluate if these settings have an impact on coating quality. Three different voltage values were used for this purpose. Hexagonal-BN was determined in FTIR spectra. RF-coating technique provided adequate adherence of BN coatings to the titanium surface. A uniform BN coating layer was formed on the titanium implants with no deformation on the titanium surface. Similar roughness values were maintained after BN coating procedure. Before coating, the contact angles of the implants were in between 63(ay) and 79(ay), whereas BN coated implants' contact angles ranged between 46(ay) and 67(ay). BN-coated implant surfaces still have hydrophilic characteristics. The change in voltage values seemed to affect the surface coating characteristics. Especially, the phase of the BN coating was different when different voltages were used. According to our results, BN coating can be sufficiently performed on pretreated implant surfaces and the characteristics of BN coated surfaces can be changed with the change in parameters of RF-magnetron sputtering system.Conference Object Citation Count: 3On the fracture prediction of 304L stainless steel sheets utilizing different hardening models(Iop Publishing Ltd, 2016) Dizaji, S. A.; Darendeliler, H.; Kaftanoglu, B.; Manufacturing EngineeringFracture prediction is one of the challenging problems in sheet metals. Forming limit curves at fracture (FLCF), as a tool to determine fracture in sheet metal processes, are obtained through the use of numerical analyses. As one of the approaches, the ductile fracture criteria (DFCs) represent the fracture initiation of the sheets formed by different loading histories. In this study, the effects of three different hardening models on different DFCs to predict the fracture for stainless steel 304L have been investigated. The results show that most of DFCs work better in the region. epsilon(2)< 0 especially with the kinematic hardening model. However, for the region. epsilon(2)> 0 where the stretching conditions are dominant, none of them could precisely estimate the fracture initiation.Article Citation Count: 13Intramedullary implants coated with cubic boron nitride enhance bone fracture healing in a rat model(Elsevier Gmbh, 2020) Ozmeric, Ahmet; Tanoglu, Oguzhan; Ocak, Mert; Celik, Hakan Hamdi; Firat, Aysegul; Kaymaz, Fevziye Figen; Kaftanoglu, Bilgin; Manufacturing EngineeringBackground: Boron nitride is a biocompatible and an osteo-inductive material for orthopedic applications. The aim of this study was to evaluate the effects of two different allotrope boron nitride coated implants, cubic boron nitride and hexagonal boron nitride, on fracture healing. Methods: In this experimental study, a total of 24 rats were divided into three groups. Group A was the control group with Kirschner wire without coating, while the wires were coated dominantly by cubic boron nitride in Group B and hexagonal boron nitride in Group C. Then a mid-third femoral fracture was created. The fracture healing was examined in terms of new bone formation with micro-CT analysis and histopathological examination, quantitative measurement of bone turnover metabolites and scintigraphic examination of osteoblastic activity on 28th day post fracture. Results: Micro-CT measurement results revealed a statistically significant increase in bone volume/tissue volume ratio and bone surface values in group B compared to group A. Cortex diameter and osteoblast counts were statistically higher in group B compared to group A. Inflammatory response was increased in group C compared to groups A and B. Biochemical test results showed significantly increased alkaline phosphatase levels and decreased osteocalcin levels in group B compared to group A. The increase in serum phosphorus and decrease in serum calcium levels was statistically significant in group C compared to Group A. Conclusion: Both types of boron nitride coating had superior fracture healing features compared to control group. Therefore, c-BN coating can accelerate the fracture healing and could lead to shorten of union time.Article Citation Count: 41Numerical investigation of coupled heat and mass transfer inside the adsorbent bed of an adsorption cooling unit(Elsevier Sci Ltd, 2012) Solmus, Ismail; Rees, D. Andrew S.; Yamali, Cemil; Baker, Derek; Kaftanoglu, Bilgin; Manufacturing EngineeringIn this study, the influence of several design parameters on the transient distributions of temperature, pressure and amount adsorbed in the radial direction of a cylindrical adsorbent bed of an adsorption cooling unit using silica gel/water have been investigated numerically. For this purpose, a transient one-dimensional local thermal non-equilibrium model that accounts for both internal and external mass transfer resistances has been developed using the local volume averaging method. For the conditions investigated, the validity of the local thermal equilibrium and spatially isobaric bed assumptions have been confirmed. To improve the performance of the bed considered, efforts should be focused on reducing heat transfer resistances and intra-particle (interior) mass transfer resistances but not inter-particle (exterior) mass transfer resistances. (C) 2011 Elsevier Ltd and IIR. All rights reserved.Conference Object Citation Count: 1Finite element analysis of non-isothermal warm deep drawing of dual phase steel(E D P Sciences, 2016) Pepelnjak, T.; Kaftanoglu, B.; Manufacturing EngineeringImproving the formability of the material is an important issue in the deep drawing process. Heating the material above its recrystallization temperature drastically increases formability but in the case of dual phase (DP) steels it results in the loss of their mechanical properties. To improve the drawing ratio, only the heating of the flange region in the warm temperature range up to 300 degrees C was studied on DP600 sheet steel by numerical simulation. Thermo-elastic-plastic FEM analysis of deep drawing at several drawing ratios was performed and compared with experimental results.Article Citation Count: 73Adsorption properties of a natural zeolite-water pair for use in adsorption cooling cycles(Elsevier Sci Ltd, 2010) Solmus, Ismail; Yamali, Cemil; Kaftanoglu, Bilgin; Baker, Derek; Caglar, Ahmet; Manufacturing EngineeringThe equilibrium adsorption capacity of water on a natural zeolite has been experimentally determined at different zeolite temperatures and water vapor pressures for use in an adsorption cooling system. The Dubinin-Astakhov adsorption equilibrium model is fitted to experimental data with an acceptable error limit. Separate correlations are obtained for adsorption and desorption processes as well as a single correlation to model both processes. The isosteric heat of adsorption of water on zeolite has been calculated using the Clausius-Clapeyron equation as a function of adsorption capacity. The cyclic adsorption capacity swing for different condenser, evaporator and adsorbent temperatures is compared with that for the following adsorbent-refrigerant pairs: activated carbon-methanol; silica gel-water; and, zeolite 13X-water. Experimental results show that the maximum adsorption capacity of natural zeolite is nearly 0.12 kg(w)/kg(ad) for zeolite temperatures and water vapor pressures in the range 40-150 degrees C and 0.87-738 kPa. (C) 2009 Elsevier Ltd. All rights reserved.Letter Citation Count: 0Theoretical modelling of magnetron sputtering of boron nitride coating(Springer Heidelberg, 2023) Rake, Nakka; Kaftanoglu, Bilgin; Hacaloglu, Tugce; Aydogan, Asude; Manufacturing EngineeringThe fundamentals of the magnetron sputtering (MS) technique are simple. However, the complex interplay of various physical and chemical sub-processes lies in its simplicity. The direct simulation Monte Carlo (DSMC) method is used to model the MS of the Boron Nitride (BN) coating. The Lorentz force, which is created by an electric field, magnetic field and particle collision, is utilised to model the BN coating. Three distinct bias voltages are used to generate three different BN-coating models under the same conditions. The modelling of BN coatings reveals that the deposition rate decreases as the substrate voltage increases.Article Citation Count: 7Experimental investigation of friction in deep drawing(Springer London Ltd, 2017) Kalkan, Hakan; Hacaloglu, Tugce; Kaftanoglu, Bilgin; Manufacturing EngineeringInvestigation of friction is carried out in the radial drawing region between the die and blank holder and also in the stretching zone over the punch in deep drawing. Two methods are developed to calculate the coefficient of friction in each zone using the experimentally determined data such as punch force diagrams and strain distributions obtained by an optical scanning system. The current methods differ from the existing techniques which are obtained in simulative tests. The proposed methods can be applied in room temperature and at elevated temperatures. Comparisons of friction coefficients are made with those obtained by other techniques.
