Прегледај по Аутор "Milutinović, Miroslav"
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- СтавкаA Comparison Study of Fatigue Behavior of S355J2+N, S690QL and X37CrMoV5-1 Steel(MDPI, 2022) Milovanović, Vladimir; Arsić, Dušan; Milutinović, Miroslav; Živković, Miroslav; Topalović, MarkoSteel of the mild-strength S355J2+N steel grade is the most often used steel for manufacturing carrying sections of constructions exposed to fatigue loads. The use of high-strength steels, such as S690QL, allows for the creation of structures that are light and simple to construct. However, increasing the yield strength of high-strength steels does not result in a corresponding increase in fatigue resistance. As a result, using high-strength steels for constructions subjected to fatigue loading can be a major design concern, raising the question of whether high-strength steels should be used at all. Most of the experimental investigations regarding the hot work tool steel X37CrMoV5-1 found in the literature are focused on its machining and wear resistance, with insufficient attention paid to the cyclic loads. This article evaluates the fatigue properties of mild-strength S355J2+N, high-strength S690QL, and X37CrMoV5-1 steel grades. A SHIMADZU servo-hydraulic testing machine is used to perform uniaxial tensile tests under uniaxial fatigue stress-controlled, fully reversed conditions (tensile–compression testing with R = 1 stress ratio) in accordance with EN ISO and ASTM standards. The aim of this paper is to highlight the fatigue characteristics of these three steels that are among the most used in their respective groups. Steel S355J2+N belongs to the group of hot-rolled normalized steels, S690QL belongs to the group of improved (quenched + tempered) steels with increased strength, and X37CrMoV5-1 belongs to the group of high-alloyed tool steels for hot work. This choice was made as the tested steels can be considered typical representatives of their groups. Based on the test results of these three steels, which are organized in S–N curves, the fatigue behavior of the entire mentioned groups of steels can be foreseen.
- СтавкаANALIZA NAPONSKOG STANJA KUKE KORIŠĆENJEM MKE(Mašinski fakultet, Univerzitet Istočno Sarajevo, 2011) Trifković, Spasoje; Radić, Nebojša; Šehovac, Savo; Košarac, Aleksandar; Milutinović, MiroslavKuka je dio koji se najviše koristi za vješanje tereta kod dizalica. Težina kuke je teret koji dizalica mora uvijek dizati, čime se smanjuje nosivost i povećava potrebna snaga dizanja. Zbog toga, dimenzije kuke treba da imaju najmanje potrebne vrijednosti, pri propisanom stepenu sigurnosti. U ovom radu je izvršena analiza naponskog stanja kuke na uobičajeni način i uz pomoć računara, koristeći metodu konačnih elemenata (MKE). Uobičajeni način proračuna kuke se sastoji u provjeri napona u vlaknima materijala u pojedinim presjecima. Krivi dio kuke je proračunat na dva načina, približnom i tačnom metodom. U prvom slučaju je kuka posmatrana kao pravi stap ekscentrično opterećen, a u drugom kao krivi štap.
- СтавкаANALYSIS OF GEAR RATIOS OF TWO DIFFERENT TYPES OF CYCLOID DRIVE TRAIN(Mašinski fakultet, Univerzitet Istočno Sarajevo, 2022) Tica, Milan; Mačkić, Tihomir; Marjanović, Nenad; Troha, Sanjin; Milutinović, Miroslav; Golubović, Dušan; Milutinović, Miroslav; Prodanović, SašaThe cyclo drive train is a special variant of the planetary drive train, where the planets are gears with a cycloid profile, while rollers are placed on the central gears (wheels). An analysis of the gear ratios of two types of cycloid drive train was performed. The first type is a classic cycloid drive train, while the second is a special variant with stepped planets. The cycloid drive with stepped planets can achieve very large gear ratios, while using central gears with a relatively small number of rollers.
- СтавкаANALYSIS OF HEAT TRANSFER THROUGH THE BEAM SUPPORT OF THE WAGON STRUCTURE CALCULATED BY SOFTWARE PAK MULTYPHISICS(Mašinski fakultet, Univerzitet Istočno Sarajevo, 2012) Nikolić, Aleksandar; Blagojević, Milan; Milovanović, Vladimir; Živković, Miroslav; Milutinović, Miroslav; Antunović, RankoPaper deals with heat transfer through beam supports of wagon structure for transportation of hot steel ingots. It is well known that changing of the material properties at high temperatures leading to reduced carrying capacity of structures. Therefore, it is necessary to know the temperature distribution in the carrying element to avoid disturbing the integrity of construction. Basic equations which governs the problem of heat transfer in terms of finite element method (FEM) are presented taking into account the initial and boundary conditions. Heat transfer through beam supports of wagon structure for transportation of hot steel ingots is solved by software PAK Multyphisics. It is shown that the temperature of carrying elements is slightly elevated, which does not affect the normal operation of wagon construction.
- СтавкаAnalysis of Power Losses in Constrained Cycloid Drive(Sveučilište u Slavonskom Brodu, Stojarski fakultet, 2023) Mačkić, Tihomir; Marjanović, Nenad; Tica, Milan; Troha, Sanjin; Milutinović, Miroslav; Rašović, Nebojša; Raos, PeroThe aim of this paper is to present a theoretical model for efficiency evaluation of a simple cycloid drive train with one degree of freedom (DOF) or constrained cycloid drive. In order to evaluate the efficiency, it is necessary to find the losses generated in the simple cycloid drive, where only losses depending on the load were considered. Expressions for determining speed ratios, efficiency, velocities and forces acting inside the cycloid drive are presented. These expressions are implemented in the theoretical model, where the places where the losses occur are defined. A computer program was created to facilitate analysis and obtain loss values based on different input data. Only load-dependent losses were considered in the theoretical model and computer program. In order to verify the theoretical model, experimental measurements were performed. A physical model of the simple cycloid drive train was created and analyzed on the test bench. The results for "S1" operating mode, i.e. when shaft 2 is stopped, show a mean value of the efficiency of 63.49%, for experimental measurements, while the mean value for theoretical analysis is 65.25%. For the operating mode "S2", i.e. with shaft 1 stopped, the mean value of the experimental measurements of the efficiency is 60.9%, while the theoretical mean value is 62.82%.
- СтавкаAnalysis of the Shifting Capabilities of Planetary Gear Trains with Coplanar Planet Gearsets(Technical University of Sofia, 2023) Vrcan, Željko; Troha, Sanjin; Marković, Kristina; Tica, Milan; Milutinović, Miroslav; Mitrev, RosenThis paper deals with the comparison of two different simple planetary gearsets. The first type is a 2k-h, variant A geartrain, while the other is a simple planetary gearset with coplanar paired planets. Methods for the kinematic synthesis of both gear trains are explored, together with the analysis of the transmission ratios that can be achieved by the gearsets. Both gear trains are analysed for the possibility of operating as a reversing gear train within their design limitations. The type with paired planets is of particular interest, as it can be built in a configuration that will have a transmission ratio of -1. This also enables compound gear trains having equal transmission ratios in both directions of rotation of the output shaft to be built.
- СтавкаApplication of Two-Carrier Planetary Gear Trains to Shifting Gearboxes(Technical University of Sofia, 2023) Troha, Sanjin; Vrcan, Željko; Marković, Kristina; Tica, Milan; Milutinović, Miroslav; Mitrev, RosenThis article deals with two-carrier planetary gearsets having two connecting and two external shafts, which may operate as two-speed gearboxes when brakes are placed on two external shafts. Analysis of the S16WN(S/E) gearbox is performed using the torque method, the specific torques are determined on all shafts, and then used to calculate both transmission ratios. The kinematic scheme of the gearbox has been synthesized, and the relative power flows have been identified. Efficiency functions are calculated for both gear ratios. The graphical representation of the transmission ratio functions for both gear ratios was used to obtain the diagram of the shifting capabilities of the S16WN(S/E) gearbox. The importance and utility of such diagrams and the relevant equations for the determination of ideal torque ratios of the component gear trains is explained. The size of the transmission ratio domain suggests that the S16WN(S/E) gearbox has a wide area of possible applications.
- СтавкаCOMPARATIVE ANALYSIS COMPETENCIES IN TRADITIONAL AND AGILE PROJECT MANAGEMENT APPROACHES(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2022) Savković, Marija; Komatina, Nikola; Nestić, Snežana; Gojković, Ranka; Golubović, Dušan; Milutinović, Miroslav; Prodanović, SašaIn order for the project to be successfully implemented, each individual involved in the project must possess appropriate competencies and skills. Competencies/skills have a great influence when assembling the project team itself and when deciding on the inclusion of new members in the existing project team. In particular, the competencies and skills of the project manager have an impact on the successful realization of the project's goals. The members of the project team must possess certain competencies/skills in order to successfully cooperate with each other and to successfully implement the tasks assigned to them. The main goal of this research paper is a comparative review and analysis of competencies/skills in traditional and agile project management approaches. Also, the paper highlights the roles, responsibilities and powers of each team member, both in the traditional and in the agile approach.
- СтавкаDesign for Reliability Based Methodology for Automotive Gearbox Load Capacity Identification(Assoc. of Mechanical Eng. and Technicians of Slovenia, 2013) Ognjanović, Milosav; Milutinović, MiroslavRobust and Axiomatic design, a property-based approach in design, is applied and integrated into a new methodology for developing Functional Requirements (FR) or Design Parameters (DP). The reliability of the design structure and the elementary reliability of the design components are used as a functional requirement of the automotive gearbox, in relation to the service life and operation conditions, and also as a design constraint in analytical relationships. For this purpose, elementary reliability and allowable stress are defined in a specific way. The automotive gearbox, operating under varying and random operation conditions, is used as a case study. The same design structure has to operate under different operation conditions. In these circumstances, the carrying capacity as a functional requirement is related to the operation conditions and operation regime. The model presented in this paper, as well as a computer program, enable identification of this carrying capacity. This paper discusses an interdisciplinary and multi-methodological integrated approach to the presented task. Experimental data regarding the failure probability of gearbox components and the probability of operation conditions processing, the decomposition of gearbox structure, and the elementary reliability treatment as a component of design property are only some of the methods applied.
- СтавкаDynamic Analysis of the Crane with Loading-unloading Trolley on the Slewing Platform(Institut IMK "14. oktobar", Kruševac, 2015) Trifković, Spasoje; Gašić, Milomir; Radić, Nebojša; Milutinović, Miroslav; Gašić, MilomirDynamic processes of the cranes with loading-unloading trolley on slewing platform are very complex and require certain simplifications, although efforts should be made to theoretically involve widest range of impacts, with respect to degree of importance of individual impacts. The study of the dynamic behavior of the cranes is very important in terms of precise determination of stress state, as well as the other characteristics of the elements and supporting structures. Dynamic loads of the cranes occur during periods of non-stationary operating regimes of any of its mechanisms. In this paper, we obtain the differential equations of motion of the cranes for some specific cases of movement, based on general multi-mass model of the crane with loading-unloading trolley on slewing platform.
- СтавкаEksperimentalno određivanje uticaja opterećenja na zagrijavanje kotrljajnog ležaja(Elektrotehnički fakultet, Univerzitet u Istočnom Sarajevu, 2017-03) Milutinović, Miroslav; Vučetić, Nikola; Trifković, Spasoje; Samardžija, Dejan; Milojković, SlobodanOsnovni zadatak ležaja jeste da omogući relativno kretanje obrtnih mašinskih dijelova tokom prenošenja opterećenja sa odgovarajućom tačnošću njihovog položaja. U toku rada obrtnih dijelova, na ležajima može doći do nastanka povišenih temperatura, koje mogu nastati usljed neispravnosti ležaja ili pak pojave preopterećenja. Radi određivanja uslova nastanka povišene temperature na kotrljanom ležaju usljed pojave preopterećenja, u ovom radu su vršena ispitivanja i upoređivanje rezultata neopterećenog i opterećenog ležaja poznatim masama. Za određivanje temperature ležaja korišćena je termovizijska kamera. Na osnovu dobijenih rezultata formiran je uporedni dijagram na kome se vidi tok zagrijavanja i hlađenja ležaja, za sva predmetna ispitivanja.
- СтавкаEXPERIMENTAL AND NUMERICAL STRENGTH ANALYSIS OF WAGON FOR CONTAINERS TRANSPORTATION(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2016) Milovanović, Vladimir; Živković, Miroslav; Jovičić, Gordana; Dišić, Aleksandar; Milutinović, Miroslav; Marković, Biljana; Antunović, RankoThis paper presents comparative experimental and numerical strength analysis of wagon for containers transportation according to the TSI standard and norm EN 12663-2:2010. The aim of this analysis is to show that results of stresses obtained by measuring with strain gauges and stresses obtained by FEM calculation gives good agreement. Based on the results and their good match, it can be concluded that the numerical FEM analysis can be reliably used for structural analysis. According to this fact, FEM analysis can reduce number of the testing new products. This leads to great savings in the design of new prototypes, in order to immediately start the process of mass production. This would lead to significantly less cost of products.
- СтавкаEXPERIMENTAL DETERMINATION OF SLIDING BEARING OPERATING TEMPERATURE(University Politehnica Timisoara, Faculty of Engineering Hunedoara, 2016) Vučetić, Nikola; Đurić, Aleksija; Milutinović, MiroslavDuring operation, it is essential to know theoperating temperature of the bearing in order to determine the thermal stability of the sliding bearing. This paper presents results of measuring the operating temperature of the sliding bearing using FLIR camera, on the testing table in the Laboratory of Applied Mechanics and Mechatronics, in Mechanical Engineering Faculty in East Sarajevo. Experimental results are presented ona diagram, followed by their comparison with the values ofthe operating temperature obtained analytically. Based on the operating temperature obtained through experiments and analytical calculation, thermal stability of the sliding bearing hasbeen tested.
- СтавкаEXPERIMENTAL VERIFICATION OF THE STRESS DISTRIBUTION IN THE CRANE MAST(Institute of Mechanical Engineering, 2009) Šarenac, Momir; Milutinović, Miroslav; Ličen, Hotimir
- СтавкаGEAR FAILURES EMBEDDED IN MANUAL GEARBOXES(University Politehnica Timisoara, Faculty of Engineering Hunedoara, 2016) Milutinović, Miroslav; Trifković, Spasoje; Đurić, Aleksija; Vučetić, NikolaDuring exploitation motor vehicle gearboxes are exposed to varying conditions. The changes are stochastic and dependent on many factors. These changes directly affect also to the gearboxes damage, and therefore the gears damage. Different types of damage can occur on gears, so that this paper will give focus on the damage on gears. According to DIN 3979 over 20 types of damage appearing on gear are given, while in this paper only damages on gears that are in gearboxes embedded will be presented. The paper contains the results of the damage percentage of manual gearboxes and the results of cumulative damage of manual six-speed gearboxes.
- СтавкаISPITIVANJE ZAMORNIH KARAKTERISTIKA LEGURE ALUMINIJUMA 242.0 S CILJEM PROCJENE INTEGRITETA AVIONSKOG CILIDARSKOG SKLOPA SA PRSLINOM(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2022) Vučetić, Nikola; Jovičić, Gordana; Antunović, Ranko; Milovanović, Vladimir; Krstić, Branimir; Jeremić, Dejan; Golubović, Dušan; Milutinović, Miroslav; Prodanović, SašaU cilju procjene integriteta cilindarskog sklopa avionskog motora Lycoming IO-360-B1F usljed pojave prsline na glavi cilindra potrebno je izvršiti niz eksperimentalnih ispitivanja legure aluminijuma 242.0 kao sastavnog materijala glave cilindra, među kojima je ispitivanje zamornih karakteristika na sobnoj i na povišenoj temperaturi. Dobijeni rezultati korišćeni su kao ulazni podaci u numeričkoj strukturnoj analizi razmatranog cilindarskog sklopa. Cilj ispitivanja materijala na zamor jeste odrediti dinamičku čvrstoću, odnosno najveći dinamički napon koji materijal pri određenom broju promjena opterećenja može da izdrži, a da pri tome ne dođe do loma.
- СтавкаMEASUREMENT OF TORQUE ON THE CARDAN SHAFT EMBEDDED IN THE FREIGHT VEHICLE(Faculty of Engineering Hunedoara, University Politehnica Timisoara, 2015) Milutinović, Miroslav; Đurić, Aleksija; Trifković, Spasoje; Vučetić, NikolaBefore analysis, development or improvement of existing structure of drive unit or gearboxes, the load that appearing in exploitation must be known. This paper presents a method of load (torque) measurement, on the cardan shaft embedded in the freight vehicle, using strain gages. The aim of the study is to determine torque variation depending on the exploitation conditions (road surface, speed transmission, vehicle load, etc). The measurement was performed for different road characteristics (vehicle movement on flat terrain, up and down the slope). Results are presented using tables and diagrams, and percentage utilization of the power drive unit, embedded into freight vehicle, was calculated based on obtained values of torque. Obtained results have an important role for designers because they give a general insight in the load on the cardan shaft , which represent the basis for future development or redesign of power unit or gearboxes and basis for forming of specter of gear load and bearing embedded into gearbox.
- СтавкаMJERENJE OBRTNOG MOMENTA NA KARDANOVOM VRATILU UGRAĐENOM U TERETNO MOTORNO VOZILO(Mašinski fakultet, Univerzitet Istočno Sarajevo, 2014) Milutinović, Miroslav; Đurić, Aleksija; Trifković, Spasoje; Vučetić, Nikola; Marković, Biljana; Antunović, RankoZa analize, razvoj ili usavršavanje postojeće konstrukcije pogonskog agregata ili mjenjačkog prenosnika potrebno je prije svega poznavanje opterećenja koje nastaju u toku eksploatacije. U radu je predstavljen način mjerenja opterećenja (obrtnog momenta), na kardanovom vratilu ugrađenom u teretno motorno vozilo, primjenom mjernih traka. Cilj rada je utvrđivanje varijacija obrtnog momenta zavisno od uslova eksploatacije (podloge puta, stepeni prenosa, opterećenja vozila, i dr.). Mjerenje je izvršeno za različite putne karakterisitke (kretanje vozila po ravnom terenu, uz i niz nagib). Rezultati su predstavljeni tabelarno i pomoću dijagrama, a na osnovu dobijenih vrijednosti obrtnog momenta izračunato je procentualno iskorišćenje snage pogonskog agregata ugrađenog u predmetno vozilo. Dobijeni rezultati imaju značajnu ulogu za konstruktore jer daje sveobuhvatnost opterećenja na kardanovom vratilu, a koji predstavljaju podlogu za budući razvoj ili rekonstrukciju pogonskog agregata ili mjenjačkog prenosnika, te osnovu za formiranje spektara opterećenja zupčanika i ležaja ugrađenih u mjenjački prenosnik.
- СтавкаPOREĐENJE REZULTATA SOPSTVENIH FREKVENCIJA KARBONSKIH NANOCIJEVI DOBIJENIH METODOM KONAČNIH ELEMENATA (MKE) I ANALITIČKOM METODOM(Mašinski fakultet, Univerzitet Istočno Sarajevo, 2014) Vučetić, Nikola; Radić, Nebojša; Milutinović, Miroslav; Trifković, Spasoje; Košarac, AleksandarKroz ovaj rad je izvršeno poređenje rezultata sopstvenih frekvencija karbonskih nanocijevi dobijenih korišćenjem MKE analize i analitičke metode. Svako tijelo ima sopstvenu frekvenciju kojom osciluje ukoliko nije izloženo dejstvu spoljašnjih sila. Cilj rada je da se utvrdi jednakopravnost MKE analize i analitičke metode u izračunavanju sopstvenih frekvencija karbonskih nanocijevi. Izračunate su sopstvene frekvencije karbonskih nanocijevi kružnog i kvadratnog poprečnog presjeka putem MKE analize i analitičke metode, te je izvršeno poređenje dobijenih rezultata prikazanih tabelarno i na dijagramima. Na osnovu dobijenih vrijednosti može se zaključiti da se odstupanja u rezultatima pri određivanju sopstvenih frekvencija nanocijevi putem MKE analize i analitičke metode nalaze u dozvoljenim granicama.
- СтавкаPROJECT METHODOLOGIES AND THEIR IMPACT ON THE PROJECT SUCCESS(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2022) Jokanović, Mirjana Đajić; El Hajjaji, Soukaina; Gojković, Ranka; Golubović, Dušan; Milutinović, Miroslav; Prodanović, SašaIt is very difficult or even impossible to know precisely at the initial planning stage what are all the activities that need to be carried out in order to complete the project and what their cost and duration parameters are. Also, this could be less or more complex, depending on the project methodology. Traditional approach consists of five phases, which include the planning phase or activity, which means that with this approach planning is imperative. On the other hand, through agile methodology, projects are typically completed in cycles with the next cycle returning to the planning phase. Nowdays it isn’t unknown that many organizations are using a combination of both agile and traditional methods (hybrib model) which may introduce more overhead in regards to additional project documentation. The purpose of this paper is to qualitatively express, based on a literature review, the influence of different project methodologies on the project success, with an emphasis on the application of the project methodologies in different branches of the economy. The results of this work should show which project methodology is best to use in which economic area, in order to more easily ensure the success of the project.