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Start Over Author "Živković, Aleksandar" Topic finite element method
5 results on '"Živković, Aleksandar"'

1. MODELING OF STATIC BEHAVIOR OF FOUR POINT CONTACT BALL BEARING.

Author

ŠEJAT, Mirjana Bojanić, ŽIVKOVIĆ, Aleksandar, KNEŽEVIĆ, Ivan, RACKOV, Milan, and MLAĐENOVIĆ, Cvijetin

Subjects
*BALL bearings, *FINITE element method, *BEHAVIORAL assessment
Abstract

Within this paper is described an analytical model for the analysis of quasistatic load distribution in four contact ball bearings. The quasistatic model was developed on the basis of the static model, applying Hertz's theory of contact and John-Harris's load distribution on ball. In this paper, the model is extended by introducing parameters such as positive/negative clearances into static equilibrium equations. Behavior analysis of the four point contact ball bearing (FKL LSQFR 308) was performed for different operating conditions. Within certain analyzes, the analysis of the influence of conceptual parameters (positive/negative clearances) on the operational characteristics of bearings was performed. The change in external load also varied. Verification of the static behavior of the ball bearing LSQFR 308 was performed by comparing the results obtained by quasistatic modeling and the results obtained using the finite element method. [ABSTRACT FROM AUTHOR]

Published
2022

2. STATIC ANALYSIS OF FOUR- POINT CONTACT BALL BEARINGS FOR AGRICULTURAL MECHANIZATION.

Author

ŽIVKOVIĆ, Aleksandar, KNEŽEV, Miloš, ZELJKOVIĆ, Milan, and MIJUŠKOVIĆ, Milivoje

Subjects
*BALL bearings, *FARM mechanization, *AXIAL loads, *RADIAL stresses, *ELASTIC deformation, *CONCRETE-filled tubes
Abstract

A four-point contact ball bearing makes it easy to simplify machine designs that have a combination of radial, axial and moment loads because it can handle all three simultaneously. They are primarily used for slow to moderate-speed applications, or where oscillatory movement is predominant such as agricultural mechanization. Four-point contact ball bearing in this paper is single row angular contact ball bearing with raceways that is designed to support axial loads in both directions. The centre points of curvature raceways on the inner and outer ring are offset relative to each other in such a way that the balls are in contact with the bearing rings at four points under radial load. For a given axial load, a radial load is also considered. This paper presents numerical model (finite element model) for computing the behavior of statically loaded ball bearings with four-point contact, for agricultural mechanization. The numerical model has to predict an influence of axial and radial load on the stress level, and elastic deformation in the explanation condition. The results show that the contact loads of four-point contact ball bearing increase with the value of clearances, small changes of the clearance have a great influence on the contact pressure. [ABSTRACT FROM AUTHOR]

Published
2020

3. Analysis of the Impact of Lubrication on the Dynamic Behavior of Ball Bearings Using Artificial Neural Networks.

Author

KNEŽEVIĆ, Ivan, ŽIVKOVIĆ, Aleksandar, RACKOV, Milan, KANOVIĆ, Željko, and BOJANIĆ ŠEJAT, Mirjana

Subjects
ARTIFICIAL neural networks, BALL bearings, LUBRICATION & lubricants, BEHAVIORAL assessment, FINITE element method
Abstract

Ball bearings can be found in all machines with rotary movement. Dynamic behavior analysis of ball bearings is a phenomenon that has been studied for many years. Previous studies on the dynamic behavior of ball bearings are based on describing the state of ball bearings using mathematical models. In addition to mathematical description, computers simulations based on finite element methods are also applied. This paper presents study of the dynamic behavior of ball bearings using artificial neural networks. Artificial neural network models are able to predict the amplitude of vibration that will generate the analyzed bearings depending on the lubrication. In this way, by the application of artificial neural networks bearing dynamic behavior can be predicted depending on the geometric parameters and lubrication. [ABSTRACT FROM AUTHOR]

Published
2019

4. PREDICTION THERMAL ELASTIC BEHAVIOR OF THE CYLINDRICAL ROLLER BEARING FOR RAILWAY VEHICLES AND CALCULATING BEARING LIFE.

Author

BLANUŠA, Vladimir, ZELJKOVIĆ, Milan, and ŽIVKOVIĆ, Aleksandar

Subjects
ROLLER bearing lubrication, FRICTION, MATHEMATICAL models, HEAT transfer, FINITE element method, STRAINS & stresses (Mechanics)
Abstract

This paper presents a calculation model the thermal elastic behavior of the cylindrical roller bearing for bearings towed vehicle in railways. The present mathematical model allows to define the value of the moment friction due to lubrication, the friction moment due to the radial and axial loads. Heat generated in the bearing calculated based on the value of previously defined moments. Also, it shows the method of calculating the coefficients of conduction and convection of heat in bearing. Using programming system general purpose analyzed thermal elastic behavior of the cylindrical roller bearing for bearings axle towed vehicle in railways. Finite element method determined by temperature values in the characteristic points of the bearing depending on the speed wheel for different time periods. Also, it determined of displacement in characteristic points of bearing due to the heat load in the steady temperature state, maximal stress and bearing life. [ABSTRACT FROM AUTHOR]

Published
2015

5. ANALYSIS OF THE BEHAVIOR OF CYLINDRICAL ROLLER BEARINGSFOR SPECIAL APPLICATIONS

Author

Blanuša, Vladimir, Zeljković, Milan, Navalušić, Slobodan, Tabaković, Slobodan, Živanović, Saša, and Živković, Aleksandar

Subjects
metod konačnih elemenata, Machine tool, glavno vreteno, vučna i vučena vozila, osovinski sklop, cilindrično valjkasti ležaj, finite element method, axle assembly, Mašina alatka, main spindle, Machine tool, main spindle, cylindrical roller bearing, towing and towingvehicles, axle assembly, finite element method, Mašina alatka, glavno vreteno, cilindrično valjkasti ležaj, vučna i vučena vozila, osovinski sklop, metod konačnih elemenata, towing and towingvehicles, cylindrical roller bearing
Abstract

U radu se razmatra problematika ponašanja cilindrično valjkastih ležaja za uležištenje glavnih vretena mašina alatki i osovinskog sklopa vučenih vozila na železnici. Za definisano konstrukciono rešenje uležištenja sklopa glavnog vretena izvršena su eksperimentalna ispitivanja toplotnog ponašanja čime su provereni i potvrđeni rezultati računarskog modelovanja (2D i 3D).U prvom poglavlju polazi se od značaja cilindrično valjkastih ležaja za uležištenje sklopova glavnih vretena i osovinskog sklopa vučenih vozila na železnici.Konstrukcioni parametri valjkastih ležaja opisani su i objašnjeni u drugom poglavlju.U trećem poglavlju izvršen je pregled stanja u oblasti u dva pravca: ponašanje sklopova glavnih vretena i osovinskih sklopova na železnici. Literaturni izvori su grupisani na one koji se bave problematikom statičkog, toplotnog ponašanja i oštećenjima ležaja.Matematički modeli za analizu statičkog, toplotnog ponašanja, veka ležaja kao i programsko rešenje za određivanje veka ležaja dati su u okviru četvrtog poglavlja. Prikazan je opšti algoritam ponašanja cilindrično valjkastih ležaja, kao i agoritmi statičkog, toplotnog ponašanja i veka ležaja. Dati su modeli za određivanje nelinearne krutosti u radijalnom pravcu za valjkaste ležaje. Na osnovu Ševalove teorije rasporeda opterećenja razvijen je nelinearni model generisanja toplote u ležaju.U petom poglavlju izvršeno je računarsko modelovanje statičkog i toplotnog ponašanja sklopa glavnog vretena uležištenog cilindrično valjkastim dvoredim ležajem. Analizirani su modeli dvodimenzionog i trodimenzionog sklopa glavnog vretena i određene su vrednosti temperature na vrhu vretena. Veličina konačnih elemenata imala je zanemarljiv uticaj na rezultate toplotnog ponašanja. U okviru ovog poglavlja ukazuje se na činjenicu da je predikcija toplotnog ponašanja mašine alatke uslovljena ponašanjem odgovarajućih sklopova, a posebno sklopa glavnog vretena.Definisanje svih izvora generisanja toplote u osovinskom sklopu kao i njihova analiza izvršeni su u okviru poglavlja šest. Potvrđena je hipoteza da na temperaturu ležaja zanemarljiv uticaj imaju generana toplota usled kotrljanja točka po šini i generisana toplota usled kočenja u odnosu na temperaturu koja se generiše u ležaju usled obrtanja i opterećenja.Sedmo poglavlje odnosi se na eksperimentalna istraživanja toplotnog ponašanja konstrukcionog rešenja sklopa glavnog vretena uležištenog cilindrično valjkastim dvoredim ležajem. Za eksperimentalna istraživanja korišćeni su savremeni merni instrumnti za merenje temperature kontaktnim i bezkontaktnim metodama.Uticaj generisane toplote usled kotrljanja točka po šini i usled kočenja eksperimentalno je ispitivan termovizijskom kamerom i prikazan u poglavlju osam.Na kraju je u poglavlju devet izvršena analiza eksperimentalnih i računarskih rezultata ponašanja valjkastih ležaja za glavna vretena, kao i analiza rezultata računarskog modelovanja ležaja za osovinske sklopove vučenih vozila na železnici.Deseto poglavlje sadrži zaključke, na osnovu rezultata pojedinih poglavlja i izvedenih istraživanja. Nakon toga dati su pravci budućih istraživanja.Jedanaesto poglavlje sadrži pregled korišćene literature, koju čini 135 literaturnih naslova od kojih je određeni broj citiran u radu., The paper deals with the problem of behavior of cylindrical roller bearings forloosening the main spindles of machine tools and the axle assembly of towedvehicles on the rail. For the defined constructional arrangement of themounting of the main spindle assembly experimental tests of thermalbehavior were performed which confirmed and confirmed the results ofcomputer modeling (2D and 3D).The first chapter starts from the significance of cylindrical roller bearings forthe installation of the main spindle assemblies and the axle assembly oftowed vehicles on the rail.The construction parameters of roller bearings (external and internal bearinggeometry and bearing lubrication) are described and explained in the secondchapter.The third chapter was conducted review of the state in the field in twodirections: the behavior of the main spindle assemblies and axle assemblieson the rail. The papers are grouped into those dealing with problems ofstatic, thermal behavior and bearing damage.Mathematical models for the analysis of static, thermal behavior, bearings lifeas well as the software solution for determining the bearing life are given inthe fourth chapter. A general algorithm behavioral for cylindrical cylindricalbearings, as well as and algorithm static, thermal behavior and bearing life.Models are given for determining nonlinear stiffness in the radial direction forroller bearings. Based on Sjoväll's theory of load distribution, a nonlinearmodel of heat generation in a bearing is developed.In the fifth chapter, a computer modeling of the static and thermal behavior ofthe main spindle assembly is carried out with a double row cylindrical rollerbearing. The two-dimensional and three-dimensional models of the mainspindle were analyzed and the temperature values at the top of the spindlewere determined. The size of the finite elements had a negligible impact onthe results of thermal behavior. Within this chapter, it is pointed out that theprediction of the thermal behavior of the machine tool is conditioned by thebehavior of the corresponding assemblies, and in particular the main spindleassembly.The definition of all sources of heat generation in the axle as well as theiranalysis were carried out under Chapter six. The hypothesis was confirmedthat the negligible impact on the bearing temperature is due to generatingheat due to rolling the wheel along the rail and generated heat due to brakingrelative to the temperature generated in the bearing due to rotation and load.Chapter Seven refers to experimental investigations of the thermal behaviorof the construction of the main spindle assembly with cylindrically cylindricaltwo-row bearing. For experimental measurements were used modernmeasurement instruments for temperature measurement by contact andwithout contact methods.The influence of generated heat due to rolling of the wheel along the rail anddue to braking was experimentally tested by a thermal camera and shown inchapter eight.In the end, in chapter nine, an analysis of the experimental and computerresults of the behavior of roller bearings for the main spindles wasperformed, as well as an analysis of the results of computer modeling ofbearings for axle assemblies of towed vehicles on the rail.Chapter ten contains conclusions, based on the results of individual chaptersand research carried out. After that, the directions of future research aregiven.Chapter eleven contains an overview of the used literature, made up of 135literary titles, of which a certain number is cited in the paper.

Published
2017

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