Person: YÜCE, CELALETTİN
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YÜCE
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CELALETTİN
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Publication Effects of drive side pressure angle on gear fatigue crack propagation life for spur gears with symmetric and asymmetric teeth(Amer Soc Mechanical Engineers, 2020-01-01) KARPAT, FATİH; DOĞAN, OĞUZ; Yılmaz, Tufan; YILMAZ, TUFAN GÜRKAN; Yüce, Celalettin; YÜCE, CELALETTİN; KARPAT, ESİN; KOPMAZ, OSMAN; Kalay, Onur Can; Mühendislik Fakültesi; Mekatronik Mühendisliği BölümüToday gears are one of the most crucial machine elements in the industry. They are used in every area of the industry. Due to the high performances of the gears, they are also used in aerospace and wind applications. In these areas due to the high torques, unstable conditions, high impact forces, etc. cracks can be seen on the gear surface. During the service life, these cracks can be propagated and gear damages can be seen due to the initial cracks. The aim of this study is to increase the fatigue crack propagation life of the spur gears by using asymmetric tooth profile.Nowadays asymmetric gears have a very important and huge usage area in the industry. In this study, the effects of drive side pressure angle on the fatigue crack propagation life are studied by using the finite element method. The initial starting points of the cracks are defined by static stress analysis. The starting angles of the cracks are defined constant at 45 degrees. The crack propagation analyses are performed in ANSYS SMART Crack-Growth module by using Paris Law. Four different drive side pressure angles (20 degrees-20 degrees, 20 degrees-25 degrees, 20 degrees-30 degrees and 20 degrees-35 degrees) are investigated in this study. As a result of the study the fatigue crack propagation life of the gears is increased dramatically when the drive side pressure angle increase. This results show that the asymmetric tooth profile not only decrease the bending stress but also increase the fatigue crack propagation life strongly.Publication Multi-response optimization for laser transmission welding of pmma to abs using taguchi-based topsis method(Sage Publications Ltd, 2023-08-01) Küçükoğlu, Ayça; Yüce, Celalettin; Sözer, İbrahim Emrah; Karpat, Fatih; Küçükoğlu, Ayça; YÜCE, CELALETTİN; KARPAT, FATİH; Mühendislik Fakültesi; 0000-0003-1387-907X; 0000-0001-8474-7328; R-3733-2017; A-5259-2018; FJI-7166-2022Recently, the usage of laser transmission welding (LTW) technology in the automotive industry has been rising for joining thermoplastic parts regarding its superior properties in comparison to other welding technologies. However, specifying the process parameters is a crucial step to obtain satisfactory welding quality for the vehicle parts. In this context, this paper addresses the LTW process of Polimetil metakrilat (PMMA) to Akrilonitril butadien stiren (ABS) materials for the production of taillights in an automotive company and proposes a new multi-response Taguchi-Based TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method to optimize machining parameters in the laser welding process. In the proposed solution methodology, the main effects of the parameters on different outputs are identified by using the L-16 orthogonal array of the Taguchi method. Regarding the best parameter set for each output, the best parameter set for multi-response is identified by using the TOPSIS method, in which alternatives are evaluated through the interrelated quality measures. To optimize welding process in taillight production, PMMA and ABS samples with the dimensions of 40 mm in width, 85 mm in length, and 2 . 7 mm in thickness are used in the experiments. The samples are welded by using LPKF Twinweld 3D 6000 (R) laser welding machine. For the welding process, laser power, welding speed, and pressure force are taken into account as the input parameters to optimize three responses: weld strength, breaking strain, and weld width. To identify the best process parameter values, the Taguchi Method is initially employed to calculate the main effects of LTW parameters for each output. Then, the TOPSIS method is carried out to evaluate a number of alternative parameter sets generated through the Taguchi results. As a consequence of the TOPSIS ranking scores, the best parameter set that jointly optimizes three outputs of the LTW process is identified for the taillight production as 60 W power, 100 mm / s speed, and 150 N pressure force. Based on the conducted experiments, this parameter setting achieves the highest weld strength, breaking strain level, and above-average weld width. The results of the experiments show that the proposed methodology is capable of optimizing LTW parameters for a multi-response with fewer experiments in the joining of plastic vehicle parts.Publication Mechanical characterization and microstructure of fiber laser welded twip980 steel depending on welding speed and focal distance(Elsevier Gmbh, 2023-01-12) Çavuşoğlu, Oktay; Yüce, Celalettin; Aydın, Hakan; Çavuşoğlu, Oktay; YÜCE, CELALETTİN; AYDIN, HAKAN; Mühendislik Fakültesi; Makine Mühendisliği Bölümü; 0000-0003-1387-907X; 0000-0001-7364-6281; JIA-6918-2023; R-3733-2017; JQB-9181-2023The TWIP steels are preferred in the automotive industry due to excellent strength and ductility. In this study, the effect of fiber laser welding parameters has been investigated on the mechanical properties and microstructural points of view twinning-induced plasticity (TWIP) steel. The variation of the mechanical properties depending on fiber laser welding parameters has been determined. The samples were laser-welded with different speeds and focal distances the laser power constant at 4 kW. The stress and elongation decreased when the welding speed increased. The highest stress was obtained at + 1 focal distance. The best energy absorption was seen in b-3 combination (laser power 4 kW, welding speed 130 mm/s, focal distance +1 mm).Publication Design and analysis of internal gears with different rim thickness and shapes(Amer Soc Mechanical Engineers, 2016-01-01) Karpat, F.; Ekwaro-Osire, S.; Yılmaz, T. G.; Doğan, O.; Yüce, C.; KARPAT, FATİH; YILMAZ, TUFAN GÜRKAN; DOĞAN, OĞUZ; YÜCE, CELALETTİN; Mühendislik Fakültesi; Makina Mühendisliği Bölümü; 0000-0001-8474-7328; 0000-0003-4203-8237; 0000-0003-1387-907X; GXH-1702-2022; AAV-7897-2020; V-6153-2017; R-3733-2017; A-5259-2018In recent years, thanks to their significant advantages such as compactness, large torque-to-weight ratio, large transmission ratios, reduced noise and vibrations, internal gears have been used in automotive and aerospace applications especially in planetary gear drives. Although internal gears have a number of advantages, they have not been studied sufficiently. Internal gears are manufactured by pinion type cutters which are nearly identical with pinion gear except the addendum factor which is 1.25 instead of 1. The tip geometry of a pinion type cutter which determines the fillet of internal gear tooth can be sharp or rounded. In this study, the design of internal gears were investigated by using a traditional approach. Mathematical equations of pinion type cutter were obtained by using differential geometry, then the equations of internal gear tooth were derived accurately by using coordinate transformations and relative motion between the pinion type cutter and internal gear blank. A computer program was generated to attain points of internal gear teeth and three dimensional design of complete gear. 20-20 were used as pressure angle. To find optimum internal gear geometry, different rim thicknesses and shapes are tried out for finite element analyses. There were several parameters that were shown to effect the performance of the internal gears, with tooth stiffness being the most significant parameter. Tooth stiffness was also vitally influence the dynamic analysis. In order to compute gear tooth stiffness of the internal gear with various rim thicknesses and shapes, finite element analysis was used. A static analysis was performed to assess the gear bending stress and tooth displacement. Tetrahedral element type was selected for meshing. The internal gear outer ring was fixed and the force of 2500 N was applied on the tooth. According to the displacement values from the analysis internal gear tooth stiffness were calculated individually. Additionally, the effect of root bending stress with varying rim thickness, shapes, and root radius were investigated. The bending stresses were calculated according to ISO 6336 and using finite element analysis were shown to be in good agreement. It was shown that when the rim thickness and fillet radius were increased, the maximum bending stresses decreased considerably. As rim thickness was increased, the maximum bending stress decreased nearly 23%. It was also shown that as the fillet radius decreased, the maximum bending stress increased, whereas the rim stresses slightly changed. As the fillet radius was decreased, the maximum bending stress increased nearly 10%. It was also observed that when rim thickness was increased, the stress on the rim was decreased, whereas tooth stiffness was increased. However, fillet radius had no visible effect both on rim stress and tooth stiffness. Furthermore, it was shown that the rim shape had significant effect on rim stress.Publication A comparative 3d finite element computational study of stress distribution and stress transfer in small-diameter conical dental implants(Univ Osijek, Tech Fac, 2021-12-01) Doğan, Oğuz; Dhanasekaran, Lokesh; Khandaker, Morshed; Kalay, Onur Can; Karaman, Hasan; Karpat, Fatih; KARPAT, FATİH; Doğan, Oguz; DOĞAN, OĞUZ; Yuce, Celalettin; YÜCE, CELALETTİN; Karpat, Esin; KARPAT, ESİN; Dhanasekaran, Lokesh; Khandaker, Morshed; Mühendislik Fakültesi; Elektrik Elektronik Mühendisliği; 0000-0001-8643-6910; 0000-0001-8474-7328; 0000-0003-1387-907X; 0000-0001-5985-7402; A-5259-2018; GXH-1702-2022; AAV-7897-2020; R-3733-2017The implant design is one of the main factors in implant stability because it affects the contact area between the bone and the implant surface and the stressstrain distribution at the bone-implant interface. In this study, the effect of different groove geometries on stress-strain distributions in small-diameter conical implants is investigated using the finite element method (FEM). Four different thread models (rectangular, buttressed, reverse buttressed, and symmetrical profile) are created by changing the groove geometry on the one-piece implants, and the obtained results are compared. The stress shielding effect is investigated through the dimensionless numbers that characterize the load-sharing between the bone-implant. It is determined that the lowest stress distribution is observed with rectangular profiled groove geometry. Besides, it is obtained that the buttressed groove geometry minimizes the stress effects transmitted to the periphery of the implant. The symmetrical profiles had better performance than rectangular profiles in stress transfer.Publication The investigation of stress distribution on the tractor clutch finger mechanism by using finite element method(Amer Soc Mechanical Engineers, 2015-01-01) Karpat, Fatih; Doğan, Oğuz; Yüce, Cellaletin; Kaya, Necmettin; Cengiz, G.; ASME; KARPAT, FATİH; DOĞAN, OĞUZ; YÜCE, CELALETTİN; KAYA, NECMETTİN; Mühendislik Fakültesi; Makine Mühendisliği Bölümü; 0000-0001-8474-7328; 0000-0003-4203-8237; 0000-0003-1387-907X; 0000-0002-8297-0777; AAV-7897-2020; R-3733-2017; GXH-1702-2022; A-5259-2018; R-4929-2018In recent years, there has been an increasing demand for tractor usage for agricultural activities in the world. Tractors are an integral part of mechanization and have a crucial role to play to enhance agricultural productivity. They are used for many kinds of farm work, under various soil and field conditions. It provides agricultural activities in challenging conditions by using several farming equipment. During the operations, tractors have to efficiently transfer power from the engine to the drive wheels and PTO through a transmission. Tractor clutch is the essential element in this system. During the torque transmission, loads which occur on the clutch components cause damages. In many cases, especially PTO clutch finger mechanism is fractured under the torque transmission.In this study, finger mechanism, which used in tractor clutch PTO disc, is investigated. Finite element analyses were performed for two different thicknesses (3.5 and 4 mm) of the finger mechanism. Stress and deformation values which occur during the transfer of power in a safe manner are investigated for these thicknesses. The finger mechanism CAD models were created using CATIA V5 and then imported into ANSYS for static finite element analyses. As a result of the analyses, approximately 13% stress decreasing was observed with the increment of the 0.5 mm for the finger thicknesses. Results from the analyses provide an accurate prediction of the material yielding and load path distribution on the PTO clutch fmaer. To verify the analyses results prototype PTO finger mechanism was manufactured and was conducted bench tests. Consequently, a good correlation was achieved between fmite element model and test results.Publication Effects of rim thickness on tooth root stress and mesh stiffness of internal gears(Amer Soc Mechanical Engineers, 2015-01-01) Yilmaz, Tufan; YILMAZ, TUFAN GÜRKAN; Yüce, Celalettin; YÜCE, CELALETTİN; Karpat, Fatih; KARPAT, FATİH; Engin, B.; Doğan, O.; DOĞAN, OĞUZ; Mühendislik Fakültesi; Makine Mühendisliği Bölümü; 0000-0001-8474-7328; 0000-0003-4203-8237; 0000-0003-1387-907X; 0000-0003-3772-7871; A-5259-2018; GXH-1702-2022; R-3733-2017; AAV-7897-2020; V-6153-2017In recent years, internal gears are used commonly in a number of automotive and aerospace applications especially in planetary gear drives. Planetary gears have many advantages such as compactness, large torque-to-weight ratio, large transmission ratios, reduced noise and vibrations. Although internal gears have many advantages, there are not enough studies on it. Designing an internal gear mechanism includes two important parameters. The gear mesh stiffness which is the main excitation source of the system. In this paper, 2D gear models are developed in order to compute gear mesh stiffness for various rim thicknesses and different rim shapes of the internal gear design. Effects of root stress with varying rim thickness and some tooth parameters are investigated by using 2D gear models. The stress calculated according to ISO 6336 and the stresses calculated against FEM are compared. These results are well-matched. It is observed that when the rim thicknesses are increased, both the maximum bending stresses and gear mesh stiffness are decreased considerably.Publication Improvement of loading capacity of internal spur gear with using asymmetric trochoid profile(Amer Soc Mechanical Engineers, 2018-01-01) Yılmaz, Tufan Gürkan; Doğan, Oğuz; Yüce, Celalettin; Karpat, Fatih; ASME; YILMAZ, TUFAN GÜRKAN; DOĞAN, OĞUZ; YÜCE, CELALETTİN; KARPAT, FATİH; Mühendislik Fakültesi; Makine Mühendisliği Bölümü; 0000-0003-3772-7871; 0000-0003-4203-8237; 0000-0003-1387-907X; 0000-0001-8474-7328; R-3733-2017; A-5259-2018; GXH-1702-2022; V-6153-2017; AAV-7897-2020Today, with numerous advantages such as reduced sliding velocity and wear, higher transmission ratio, higher running efficiency etc., internal spur gears are used in several industrial applications. An internal gear is generated by pinion cutters towards inside of gear blank opposite of external gear. In this study, bending stress of internal spur gear with the asymmetric trochoid profile is investigated. Asymmetry is ensured by using pinion cutter has different tip radius value on its right and left side. This situation is allowed to use larger tip radius on one side. The limit value of tip radius is defined with taking into account cutter addendum height and interference possibility for the given pinion gear parameters. On the other side, asymmetry on the involute region is also examined. Firstly, a mathematical equation of pinion cutter is derived then points of internal gear are obtained by using coordinate transformation, differential geometry and gearing theory in MATLAB. Points of internal gear are exported to CATIA to realize the 3D design. Case studies are conducted for determining the relation between tip radius and pressure angle on bending stress separately with ANSYS program. According to preliminary results, using asymmetric trochoid profile reduces approximately 16% bending stress of internal spur gear.Publication Influence of heat input on mechanical properties and microstructure of laser welded dissimilar galvanized steel-aluminum joints(Amer Soc Mechanical Engineers, 2018-01-01) Yüce, Celalettin; Karpat, Fatih; Yavuz, Nurettin; ASME; YÜCE, CELALETTİN; KARPAT, FATİH; YAVUZ, NURETTİN; Mühendislik Fakültesi; Makina Mühendisliği Bölümü; 0000-0003-1387-907X; 0000-0001-8474-7328; A-5259-2018; R-3733-2017; GKI-9429-2022The hybrid structures of aluminum-steel have been increasingly used for body-in-white constructions in order to reduce weight and green gas emissions. Obtaining acceptable joints between steel and aluminum required a better understanding of welding metallurgy and their effects on the resultant mechanical properties as well as the microstructure of the joints. In this research, the fiber laser welding of zero-gap galvanized steel and aluminum alloy in an overlapped configuration was carried out. The influence of heat input on the weld bead dimension, microstructural and mechanical properties of the joints was studied. A detailed study was conducted on the effects of the heat input on the penetration depth, weld width and microstructure of the laser welded dissimilar joints by means of an optical microscopy. A scanning electron microscopy with energy dispersive spectroscopy was carried out to determine the atomic percent of the elements for intermetallic compounds (IMC) occurred at the interface of the aluminum and steel. Microhardness measurement and tensile shear tests were conducted to evaluate the mechanical properties of the galvanized steel to aluminum lap joints. The experimental results showed that the penetration depth and weld width increased with the increase of heat input level. However, in order to limit IMC layer thickness and hardness at the surface of the weld seam and aluminum alloy, iron to aluminum dilution should be restricted by limiting the penetration depth. At lower heat input levels, less brittle IMC formation was formed. Consequently, with limited penetration depths at low heat input levels, up to 520 N tensile shear load achieved, with failures located in the interface of the joints.Publication Experimental investigation of the impact resistance of involute spur gears(IEEE, 2018-01-01) Doğan, Oğuz; Yüce, Celalettin; Karpat, Fatih; Kalay, Onur Can; IEEE; DOĞAN, OĞUZ; YÜCE, CELALETTİN; KARPAT, FATİH; Kalay, Onur Can; Mühendislik Fakültesi; 0000-0003-4203-8237; 0000-0003-1387-907X; 0000-0001-8474-7328; 0000-0001-8643-6910; A-5259-2018; GXH-1702-2022; R-3733-2017; GDQ-4936-2022Gears are the most commonly used power transmission element in today's world. Due to their advantages, gears are widely used in many sectors such as aerospace, space, wind turbines, automotive, etc. In these sectors the moment, speed and power values that need to be transmitted are increasing day by day. Due to the increased power and moment values, gears are exposed to high dynamic, impact loads and they are subject to damage due to these loads. For this reason, the impact resistance of the gears must be determined carefully in the design phase of the gear. In this study, an experimental method for determining impact loads of the gears is developed. A special drop gear impact test setup is designed and manufactured to determine the impact loads on the gear. The test setup works by dropping the load on the gear tooth from a certain height. In this way, the teeth are broken and the impact load, acceleration and displacement values are measured by using special measurement instruments which are attached on the test setup. The effect of surface hardness on impact loads is investigated. Two different gear samples are used in the experiments. It is seen that the surface hardness has great effect on the impact loads of the gears. It has been found that surface hardened gears have much higher impact strength than unhardened gears.