Tuncay Karacay

Tuncay Karacay
Gazi University · Department of Mechanical Engineering

PhD

About

38
Publications
6,605
Reads
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252
Citations
Additional affiliations
October 2017 - present
Gazi University
Position
  • Professor (Associate)
January 2009 - October 2017
Gazi University
Position
  • Professor (Assistant)

Publications

Publications (38)
Article
Full-text available
The vibrations of a shaft in rotary mechanical systems supported by angular contact ball bearings are investigated theoretically and experimentally for various preloads in this paper. In the theoretical part of the study, a dynamic bearing model is presented, a rigid shaft supported by EHL angular contact bearing has been modelled as 5 DoF. Non-lin...
Article
Aerostatic journal bearing applications mainly focus on high-speed precision machining, so predictable and smooth functioning of the system is crucial. Air is supplied to the bearing through a number of orifices and any unevenness in the size of these orifices will affect the performance of the system. The size difference could be due to manufactur...
Conference Paper
Full-text available
Aerostatik yataklar, yağlayıcı hava filmi tabakaları arasındaki sürtünme kayıplarının sıvı yağlayıcılara göre oldukça düşük olması sayesinde yüksek hızlarda dönen şaftlar için elverişlidirler. Ancak havanın sıkıştırılabilirlik özelliği sebebiyle yatağın dinamik karakteristikleri doğrusal değildir. Bundan dolayı aerostatik yataklar ile desteklenmiş...
Article
In this study, the pneumatic hammer instability phenomena in the aerostatic journal bearing–rotor system is analysed and discussed for different feeding hole configurations theoretically and experimentally. The influences of the configuration of the feeding holes on the nonlinear dynamics of the system are also investigated. The air flow between th...
Article
Full-text available
Giriş Krank kasnakları, krank millerinde düzensiz piston patlamalarından meydana gelen burulma titreşimlerini azaltan ve aynı zamanda aktarma organı olarak görev yapan bir motor elemanıdır. Krank kasnakları ayarlı kütle sönümleyici prensibiyle çalışmaktadır. Ayarlı kütle sönümleyiciler, ana kütlenin rezonans frekansına göre ayarlanan ve böylece sis...
Conference Paper
Full-text available
Dynamics and vibrations of the shafts show to varies by dynamic characteristics of the bearing. Load capacity of the bearing, in other words, stiffness of the bearing affects natural frequency of the shaft vibration known as critical speeds. In aerostatic bearings, pressurized air which is supplied between the shaft and bearing surfaces with feedin...
Article
Full-text available
Torsional vibration occurs in the crankshaft of an internal combustion engine due to the sudden burst in the firing orders. The torsional vibration dampers (TVD) are used to reduce these torsional vibrations. TVD's although it has different types, consist of a pulley, inertia ring and vulcanized rubber that connects the two parts to the hub, it wor...
Article
Full-text available
Bu çalışmada, yüzey pürüzlülüğünün, basınçlı hava yatağı ile desteklenmiş bir yatak-rotor sisteminin yük taşıma kapasitesine olan etkileri teorik olarak araştırılmıştır. Bu kapsamda yatak ve rotor yüzeyleri arasındaki havanın akışı, Reynold's denklemi ile modellenmiştir. Bu model içerisindeki, yatak ve rotor yüzeyleri arasındaki mesafeyi tanımlayan...
Conference Paper
Full-text available
zet—Bu çalışmada basınçlı hava yatakları ile desteklenmiş bir yatak-şaft sisteminde, yatak ve şaft yüzeyleri arasındaki ince hava filminin sürtünme karakteristiği teorik olarak araştırılmıştır. Bu kapsamda yatak ve şaft yüzeyleri arasındaki havanın hareketi Reynold's denklemi ile modellenmiş ve bu model sayısal olarak çözülüp yüzeyler arasındaki ba...
Article
In this study, the performance of a rotor system supported by externally pressurized air bearing was investigated. Angular misalignment was introduced to the bearing along two perpendicular direction separately, and then both at the same time (combined). The effect of angular misalignment to the pressure distribution in the air bearing was obtained...
Poster
DESIGN and ANALYSIS of AIRLESS TIRE
Article
Full-text available
In the externally pressurized air bearing-rotor system, characteristic of air flow between rotor and bearing directly effects dynamics of bearing-rotor system. Mathematical model of the air flow and numerical solution of this model are very important in externally pressurized air bearing. The air flow is modelled using Reynold's equation and pressu...
Conference Paper
In this study, vibrations of a rotor-bearing system supported by tilted air bearing are numerically investigated. Air flow between rotor and bearing surfaces is modelled using Reynold's equation with an introduced new clearance function for tilted air bearing. In order to calculate air film forces, Reynold's equation is solved using Differential Tr...
Conference Paper
Seismic signals which are generated by human footsteps could be used in intrusion. Feature extraction is the most important step of the target detection and classification. In this study, vibration signals, which are generated by human steps, are analyzed for intrusion detection. A test set-up is established for measuring seismic signals equipped w...
Conference Paper
Dynamics of the bearing-rotor system supported by aerostatic bearing directly relate to geometric parameters of the system and mass flow rate which is supplied to radial clearance. Manufacturing defects and operational failures could cause serious problem by affecting the geometric parameters and the mass flow rate. In this study, effects of sudden...
Conference Paper
Full-text available
zet Basınçlı hava yatağı ile desteklenmiş yatak-rotor sistemlerinin dinamiği, sistemin geometrik parametreleri ve radyal boşluğa iletilen hava miktarı ile doğrudan ilişkilidir. İmalat hataları ve sistemin çalışması esnasında meydana gelebilecek hatalar, sistemin geometrik parametreleri ve hava miktarını etkileyerek, ciddi problemlere sebep olabilir...
Conference Paper
Full-text available
Basınçlı hava yatakları ile desteklenmiş yatak-rotor sistemlerinde, dışarıdan basınçlandırılarak yatak ve rotor yüzeyleri arasındaki radyal boşluğa iletilen hava, rotoru destekleyerek, iki yüzeyin birbirine temas etmeden çalışmasını sağlar. Dolayısıyla, yatak-rotor sisteminin çalışması süresince, rotorun dinamik hareketleri ile yatak ve rotor yüzey...
Conference Paper
Full-text available
Özet—İnsanlar bir bölgede hareket ettikçe, hareketin gerçekleştiği zemin üzerinde periyodik darbeler oluşmaktadır. Bu darbeler zeminde düzensizliklerin oluşmasına sebep olur ve bu düzensizlikler, darbe kaynağından sismik dalgalar şeklinde yayılır. Bu çalışmada insan hedeflerin tespiti amacıyla, adım sonucu oluşan sismik sinyaller incelenmiştir. Sis...
Conference Paper
Full-text available
In this study, effects of surface roughness of the bearing surface on the dynamic of a rotor supported by aerostatic bearing are theoretically investigated. In order to analyze the dynamics of the bearing-rotor system, air flow between rotor and bearing surfaces is modelled using the Reynold's equation. In this air flow model, clearance function wh...
Conference Paper
Full-text available
In externally pressurized air lubricated bearing, air is generally supplied with constant pressure by orifices. Radial loads (rotor mass or external forces on rotor) make a relative eccentricity between bearing and rotor. And the relationship between the load and the eccentricity is nonlinear due to compressibility of air. Increase in the eccentric...
Conference Paper
Full-text available
Basınçlı hava yataklarında, yatak ve rotor yüzeylerine iletilen basınçlı hava, bu iki yüzeyin birbirine temas etmesini önler ve yağlayıcı görevi görür. Yatak-rotor sisteminin dinamiğinin incelenmesi için, yatak ve rotor yüzeyleri arasındaki bu akışın modellenmesi ve bu modelin çözülerek yağlayıcı film kuvvetlerinin, yani basınç dağılımlarının elde...
Conference Paper
Full-text available
Dynamics of a rotor supported by air bearings is strongly depends on the pressure distribution between the rotor and the bearing. In this study, internal pressure in air bearings is numerical and experimental analyzed for different radial clearances. Firstly the pressure distribution between rotor and bearing is modeled using Reynold's equation and...
Conference Paper
Full-text available
zet—Basınçlı hava yatağı ile desteklenmiş rotorların dinamiği, yatak ve rotor arasındaki ince hava filmi ile doğrudan ilişkilidir. Bu çalışmada iki ucundan radyal basınçlı hava yatakları ile desteklenmiş yatak-rotor sisteminin dinamik davranışlarının incelenebilmesi ve kurulan matematiksel modellerin doğrulanması için bir deney düzeneği tasarımı ge...
Article
Full-text available
People moving on a ground generate a consecutive impact which excites the ground and vibrations spread as seismic waves expanding from the source. Seismic level vibrations could be used to detect human intruders. In this study, ground vibrations are acquired and analyzed by dividing the time history into windowed segments. In order to collect vibra...
Article
Full-text available
Performance parameters such as critical speed and stability are affected by various design parameters such as supply pressure, clearance between shaft and rotor (air film thickness), bearing diameter and length etc. for externally pressurized gas lubricated bearing. Literature about effects of supply pressure is generally analyzed with clearances w...
Article
Full-text available
In this study, a new coating procedure deploying plasma spraying technique for zirconia (ZrO2) powder on aluminum substrate has been studied. Zirconia coating was applied with/without bond layer between the Ni–Al coating and the substrate. Ni–Al powders are mainly used as bond coat, which is also known as composite bonding. Thermal torch and therma...
Conference Paper
This paper studies mathematical model of a Vertical Roller Mill (VRM). VRMs are widely used in cement, chemical, coal and electricity industries to reduce particle sizes of raw materials to a desired value by using both compression and shear forces. Although there are various studies in the fields of both modeling of grinding process of raw materia...
Conference Paper
The main aim of this study is to determine vibration characteristics of a vertical roller mill for a range of variables. A vertical roller mill which is manufactured by Ersel Heavy Machinery Inc. is analyzed to investigate stable and unstable vibration characteristics. First, a mathematical model of the vertical roller mill is derived and by using...
Article
Vibration measurements and signal analysis is widely used for condition monitoring of ball bearings as their vibration signature reveals important information about the defect development within them. Time domain analysis of vibration signature such as peak-to-peak amplitude, root mean square, Crest factor and kurtosis indicates defects in ball bea...
Article
Full-text available
Condition monitoring of ball bearings by analyzing vibration signals is successfully applied both numerically and experimentally. The most critic point in vibration analysis is early and successful detection of defect formation. The characteristic vibrations due to these defects ought to be understood well enough for this reason. In this study, loc...
Article
In the current paper, the radial, axial, rocking, and yawing vibrations of a rigid grinding spindle supported by a pair of angular contact ball bearings are studied. A computer program was developed to simulate the dynamic behaviour of the spindle and results are presented in the time, frequency, and waterfall diagrams. Results from the simulations...
Article
Full-text available
In this study, the variations of machining performance outputs, namely workpiece surface roughness, surface profile power spectral density, workpiece removal rate, electrode wear rate, relative wear, workpiece surface hardness, and workpiece surface microstructure were experimentally investigated with the varying machining parameters for metal powd...
Article
Full-text available
Ride characteristics of a vehicle moving on a rough ground with changing travel velocity are analyzed in this paper. The solution is difficult due to the non-stationary characteristics of the problem. Hence a new technique has been proposed to overcome this difficulty. This new technique is employed in the analysis of ride characteristics of a vehi...
Article
Full-text available
Ride characteristic of a vehicle moving on a rough ground with changing travel velocity is analyzed in this paper. Solution is difficult due to the non-stationary characteristic of the problem, so a new technique has been developed to analyze ride characteristic of a vehicle with changing velocity in time/frequency domain. This new technique is sho...
Article
Full-text available
Parallel to the increase in the number of people preferring camp holidays, personal trailer usage have shown an increasing tendency in the last years. In this study, therefore, a relation between the load carriage capacity and loaded weight of a personal trailer is searched for a real road input data. In modeling, a half- car approach, which is use...

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Projects

Project (1)
Project
To achieve deep understanding of bearing vibrations