Прегледај по Аутор "Marković, Biljana"
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- СтавкаANALITIČKO ODREĐIVANJE SOPSTVENIH FREKVENCIJA POGONSKOG VRATILA(Univerzitet u Istočnom Sarajevu, Mašinski fakultet Istočno Sarajevo, 2016-12) Vučetić, Nikola; Košarac, Aleksandar; Blagojević, Mirko; Antunović, Ranko; Marković, Biljana; Antunović, RankoModalna analiza je dinamička analiza linearnih sistema sa N stepeni slobode koja se zasniva na metodi razvijanja po vlastitim oblicima ili tonovima. Kroz ovaj rad je prikazano analitičko određivanje sopstvenih frekvencija oscilovanja pogonskog vratila mjenjačkog prenosnika snage DMB 6.80.235 primjenom Ojler-Bernulijeve teorije greda. Dobijeni rezultati su poređeni sa rezultatima sopstvenih frekvencija baziranim na ranijim istraživanjima, a dobijenim na osnovu eksperimentalne postavke, kao i numeričkim putem uz upotrebu software-a Ansys Workbench 12.1. Konačan cilj rada je dobijanje pouzdanog matematičkog modela sprezanjem parcijanih prenosnih funkcija.
- СтавкаAnalysis of the wind effect on the mechanical structures in the case of the four-side sunshade(2019) Marković, Biljana; Krajišnik, Milija; Đurić, AleksijaThis paper presents the analysis of the wind effect of four-side sunshade construction. The aim of the paper is to demonstrate the possibility of applying analogy in research, with examples from civil constructions, in order to simplify and reduce the analysis. The paper presents the analytical calculation of the pressure on the sides of the four-sided sunshade, analogously to the calculation of pressure on the four-sided roofs of civil construction objects.
- СтавкаBiomimetics Design for Tribological Applications(Fakultet inženjerskih nauka, Kragujevac, 2018) Ivanović, Lozica; Vencl, Aleksandar; Blaža, Stojanović; Marković, BiljanaBiomimetics, biomimicry and bionics are synonyms for the scientific discipline of creating new structures inspired by nature. Biomimetics systematically analyses the evolutionary processes of living organisms, their structural relationships, the characteristics of natural materials and it studies how this knowledge can be used to create the optimal products and new sustainable materials. In the past decade, the biomimetics has received an incentive for the development by the technology modernization, and above all, by making it possible to study the micro- and nanolevels of biological structures. On the other hand, the miniaturization of technological devices has increased the need to understand the tribological phenomena on micro- and nanolevel, where is a huge potential for technological innovation. The integration of advanced research methods made it possible to discover new aspects in the structure and properties of biological materials and transfer that knowledge into new concepts or products. State-of-the-art of biomimetics progress is discussed, as well as, its goals and the potential to simultaneously achieve the financial and ecological contribution by realization of bio-inspired concepts. An overview of biomimetic researches is also provided, with special emphasis on the possibility of their tribological applications. The characteristic examples have been presented and those examples show how the structural and mechanical properties of the material were used as the basis for developing new creative solutions to solve the problem of friction in engineering applications.
- СтавкаBiomimetics Design for Tribological Applications(Faculty of Engineering Sciences, Kragujevac, 2018) Ivanović, Lozica; Vencl, Aleksandar; Stojanović, Blaža; Marković, BiljanaBiomimetics, biomimicry and bionics are synonyms for the scientific discipline of creating new structures inspired by nature. Biomimetics systematically analyses the evolutionary processes of living organisms, their structural relationships, the characteristics of natural materials and it studies how this knowledge can be used to create the optimal products and new sustainable materials. In the past decade, the biomimetics has received an incentive for the development by the technology modernization, and above all, by making it possible to study the micro- and nanolevels of biological structures. On the other hand, the miniaturization of technological devices has increased the need to understand the tribological phenomena on micro- and nanolevel, where is a huge potential for technological innovation. The integration of advanced research methods made it possible to discover new aspects in the structure and properties of biological materials and transfer that knowledge into new concepts or products. State-of-the-art of biomimetics progress is discussed, as well as, its goals and the potential to simultaneously achieve the financial and ecological contribution by realization of bio-inspired concepts. An overview of biomimetic researches is also provided, with special emphasis on the possibility of their tribological applications. The characteristic examples have been presented and those examples show how the structural and mechanical properties of the material were used as the basis for developing new creative solutions to solve the problem of friction in engineering applications.
- СтавкаCALCULATION OF LBKz FACTOR FOR CARBON FIBER REINFORCED POLYMER UNDER COMPRESSION AND THEIR COMPARISON WITH OTHER LIGHTWEIGHT MATERIALS(University Politehnica Timisoara, Faculty of Engineering Hunedoara, 2018) Đurić, Aleksija; Marković, BiljanaThe aim of this paper is to show which material, based on the LBKz factor, is more applicable in lightweight constructions. The LBKz factor has been calculated for three different groups of material (CFRP, hybrid laminates and materials applicable in additive technologies), and the calculation was based on the results obtained from our own experimental testing, as well as from the research results shown in available papers of other authors. The experimental compression testing was performed on the CFRP material.
- СтавкаCALCULATION OF THE BEARING MODIFIED RATING LIFE DURING NEW BEARING DESIGN(University Politehnica Timisoara, Faculty of Engineering Hunedoara, 2017) Marković, Biljana; Divčić, MiodragBearings, as a mechanical elements that allow relative movement of rotating parts while transferring loads between them, are primary in the most demanding sectors of machine industry, as automotive and aerospace industry, and they are required to have extremely high level of accuracy of manufacturing and meet the requirements prescribed by international standards. Producers specialized in the production of highly demanding types of bearings must prove eligibility criteria defined in ISO 281:2007 and ISO/TS 16281/2008 specification. This paper deals with the bearing testing results by manufacturer and research of the basic and modified rating life of bearings, the winning of new types of bearings, in accordance with the relevant specifications.
- СтавкаDETERMINATION OF LOAD SPECTRUM OF BUCKET WHEEL EXCAVATOR SRS 1300 IN COAL STRIP MINE DRMNO(University of Zagreb, Croatia, 2013) Milčić, Dragan ; Miladinović, Slobodan ; Mijajlović, Miroslav ; Marković, BiljanaToothed gear power transmissions are complex mechanical systems and their design is a very challenging engineering task that requires the application of common calculation procedures and contemporary designing methods. Operating conditions of the gear power transmission are important for the design process from the aspect of overload prediction and they are defined within the design process by the operating condition factor KA, which has a wide range of values (1 to 2.5), prescribing various operating situations. However, a good design of the toothed gear power transmission can be achieved if operating conditions are simulated and as such implemented in the calculation/design procedure. Such improvement in the design process can be done with the use of defined load spectra that accurately describe realistic operating conditions. The paper presents the results of tensiometric measurements of torque at the output shaft of the working wheel gearbox of the bucket wheel excavator SRs 1300 TAKRAF in the coal strip mine Drmno, and gives a definition of appropriate load spectra based on these tensiometric measurements. The load spectra are defined by applying the full cycle discretization method and as such afterwards used for the calculations/design of the working wheel of the bucket wheel excavator (gears, shafts, shaft keys etc.).
- СтавкаDEVELOPMENT OF NEW PRODUCTS IN INDUSTRY OF UPHOLSTERD FURNITURE(University Politehnica Timisoara, Faculty of Engineering Hunedoara, 2015) Pelkić, Srđan; Đurić, Aleksija; Marković, Biljana; Vučinić, RadivojkaThis paper presents the development phases of new products in the upholstered furniture industry, ranging from market research to mass production. During the development of the new products, teams od experts from various fields are included, such as: mechanical engineering, chemistry, architecture, economics, which has been discussed in this paper. Also, for preparation of this paper has been used CAD/CAM technology, without which is unthinkable to develop new products today. The emphasis, during the development of new product, is put on flexibility of product, price, quick and simple installation, improvement of productivity, materials, environmental standards and specifications, transport and packaging, marking and identification of products in stock, technical documentation, making the zero batch and, at the end, batch production, i.e. at all stages and elements essentials for the development of new products, which target is competitiveness in the market of upholstered furniture.
- СтавкаEMOTIONAL DESIGN AND QUALITY OF LIFE(Center for Quality, Faculty of Engineering, University of Kragujevac, 2017) Ivanović, Lozica; Marković, Biljana; Arsovski, Slavko; Rackov, Milan; Kuzmanović, SinišaLately, the concept of emotional design, which implies the concept of improving the quality of life, happiness and satisfaction of a man, has greatly attracted the attention of the academic community. Since this concept is multidimensional, one of the aspects, which the scientists are particularly focused on, is involvement of man's emotional needs in the process of product design. A successful development of a new product implies satisfaction of customers' requirements to the level of their individual wishes which include emotions as well. Therefore, the aim of this paper is to describe the emotional design, the present state of understanding the concept, its characteristics and aims. Some characteristic examples which illustrate the described concept, and whose design evokes positive emotions, are presented in the paper. The emphasis has been put on the importance of a specific aspect of an emotional approach to design through development of innovative, sustainable products with the aim to increase the quality of life.
- СтавкаENERGETSKI INDEKS PROIZVODNJE DRVNOG ČIPSA(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2016) Vasković, Srđan; Gvero, Petar; Medaković, Vlado; Halilović, Velid; Ikić, Marko; Ašonja, Goran; Marković, Biljana; Antunović, RankoProizvodnja čvrstih biogrova definisana je odgovarajućim energetskim lancem snabdijevanja. Proces proizvodnje čvrstih goriva iz drvne biomase počinje sa tehnologijama za skupljanje drvnog ostatka, počev od obaranja stabla pa sve do sistema za preradu (za usitnjavanje, drobljenje, sušenje, presovanje ukoliko se pravi briket ili pelet). Efikasnost proizvodnje drvnog čipsa je u relaciji sa ukupnom uloženom energijom po 1 kWh donje toplotne moći proizvedenog goriva. Ovaj rad će prikazati analizu ukupno uložene energije u snabdijevačkom lanacu proizvodnje drvnog čipsa u funkciji od transportnih distanci i vlage u drvetu. Model za analizu energetskog indeksa proizvodnje drvnog čipsa urađen je u softverskom paketu Mathcad.
- 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 MEASUREMENT OF SLIDING BEARING TEMPERATURE USING THERMOGRAPHY(Faculty of Engineering Hunedoara, University Politehnica Timisoara, 2019) Moljević, Slaviša; Đurić, Aleksija; Gojković, Ranka; Marković, BiljanaIn this paper is shown an example of the use of thermography in the measurement of temperature of the sliding bearings. The temperature is very important by sliding bearings, so it is necessary to measure frequently and the contactless gauges allow it in a very simple way. This paper shows that the measurement is bit dependent on the manufacturer of the camera that measures the temperature, it is important that the camera is intended for such measurements and that the basic parameters such as emissivity and measurement distance are well adjusted. Different camera manufacturers enrich accessories, which certainly helps users to handle the camera more easily, but from the aspect of temperature accuracy, cameras of the same characteristics give approximately similar results.
- СтавкаFEASIBILITY STUDY FOR REPLACMENT HEATING SYSTEM ON NATURAL GAS WITH PELLET BOILERS AT PRIMARY SCHOOL "SVETI SAVA " IN LUKAVICA(Mašinski fakultet, Univerzitet Istočno Sarajevo, 2014) Vasković, Srđan; Gvero, Petar; Medaković, Vlado; Halilović, Velid; Milić, Davor; Marković, Biljana; Antunović, Ranko; Kraišnik, MilijaThis study describes the possibility of installation of pellet boilers for the production of thermal energy for heating in the primary school "Sveti Sava" in Lukavica. Existing heating system with natural gas turned out to be very expensive with high costs in terms of consumption of natural gas on annual level but also due to the high price of natural gas. Alternative possibility of heating premises within the school is seen in the installation of boilers that use wood pellets as an energy source. Above all, wood pellet represents an environmentally clean fuel in terms of CO2 emissions, but also because of the availability of resource from nearby factories that produce pellets, it can be used as a domestic fuel. In this way, the story of sustainable community development is encouraged, as well as the flow of capital within the community is closed .
- СтавкаHOW TO REACH INNOVATIVE PRODUCT BY KNOWLEDGE TRANSFER?(University Politehnica Timisoara, Faculty of Engineering Hunedoara, 2010) Marković, Biljana; Miltenović, VojislavThe aim of every company, in modern conditions for the foreseeing, is to become available at global market. Creation of an innovative (new) product represents the key to success in global environment, while team work and use of demonstrated results of existing educative models represent the condition for creation of such a product. This paper shows results of knowledge transfer and implementation of the educative model KaLeP in education of mechanical engineers in Serbia. Major problem in modern world market is – how to create new innovative product which will fulfils all customers’ requirements and expectations? The above-mentioned means that new products are created in severe market competition which should fulfil customers’ expectations, even their individual wishes, which as result has striving for “innovative production”, and/or “innovative management”. The only possible solution in such actual environment conditions is application of one of the global development strategies, integrated product development. It is only mean for obtaining better, innovative design solution which is nowadays primary objective of any company. The objective of the university education of mechanical engineers is to impart the complex knowledge necessary for efficient product development in an industrial environment and to teach students the key abilities required for their professional life. Industry is searching for engineers with a university degree as a “problem solvers” and “creativity sources”.
- СтавкаIMPLEMENTACIJA SISTEMA UPRAVLJANJA ENERGIJOM ISO 50001:2011 U BIH(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2016) Gojković, Ranka; Moljević, Slaviša; Gordić, Dušan; Marković, Biljana; Antunović, RankoPotreba za pravilnim korištenjem energetskih resursa i obnovljivih izvora energije dovela je do uspostavljanja novog međunarodnog standarda u cilju sprečavanja nepravilne potrošnje energije i smanjenja zagađivača životne sredine. Svrha ovog standarda je da omogući organizacijama da uspostave sistem i procese potrebne za poboljšanje energetskih performansi, uključujući i energetsku efikasnost, korištenje i potrošnju. Implementacija sistema za upravljanje energijom, pomaže organizacijama u planiranju radi smanjenja troškova energenata, optimizaciji primjene energije, smanjenja zagađivanja životne sredine i obezbjeđenje odgovarajućeg sadržaja energije proporcionalnog kvaliteta i troškova.
- СтавкаKOMPARACIJA EMISIJA CO2 ZA SNABDIJEVAČKE LANCE GORIVIMA OD DRVNE BIOMASE I UGLJA(Mašinski fakultet Istočno Sarajevo, Univerzitet u Istočnom Sarajevu, 2016) Mrkić, Maja Bosančić; Vasković, Srđan; Gvero, Petar; Halilović, Velid; Petrović, Daliborka; Marković, Biljana; Antunović, RankoPotrošnja fosilnih goriva za aktiviranje mehanizacije za prikuplјanje, transport i preradu biomase u neku vrstu čvrstih goriva stvara određenu količinu uglјen – dioksida (CO2) koja se emituje u atmosferu. S druge strane ako se posmatra jedan snabdijevački lanac energijom iz fosilnog goriva (uglja) tada imamo isto sličnu situaciju što se tiče emisija za aktivaciju mehanizacije. Međutim, ključna razlika je u tome što sagorijevanje biomase u nekom postrojenju tretira se kao CO2 neutralno, dok se kod sagorijevanja uglja uzima ekvivalentna vrijednost emisije CO2 jer se u pitanju fosilno gorivo. Ovaj rad vrši komparaciju emisija koje se pojavljuju u ova dva tipa energetskih lanca.
- СтавкаLAYER THICKNESS INFLUENCE OF MACRO- AND MICROSTRUCTURE QUALITY OF 3D PRINTED PARTS(Faculty of Engineering, University of Kragujevac, 2019) Đurić, Aleksija; Gojković, Ranka; Marković, Biljana; Moljević, Slaviša; Anić, JelicaIn this paper will be analyzed the influence of the layer thickness on the micro and macro structure of the parts obtained by 3D printing, i.e. fused filament fabrication (FFF) technology. Specimens for analysis will be printed on the 3D printer Zotrax M 200, and the macro and microstructure will be done on the VHX 6000 microscope. It will be shown in the paper that by increasing the thickness of the layer, the time required for the production of the part will be significantly reduced, but also the quality of the surface is also significantly affected.
- СтавкаMicrostructure and Fatigue Properties of Resistance Element Welded Joints of DP500 Steel and AW 5754 H22 Aluminum Alloy(MDPI, 2022-02-14) Đurić, Aleksija; Milčić, Dragan; Burzić, Zijah; Klobočar, Damjan; Milčić, Miodrag; Marković, Biljana; Krstić, VladislavThe modern concept of lightweight design (LW) requires the application of different materials in one structure (multi-material structures). The structure of different materials has a good perspective for application in the automotive and aerospace industries but only if it is possible to achieve a quality joint between different materials. The most used technology for joining different materials in the automotive industry is Resistance spot welding (RSW). Due to different mechanical, physical, and chemical properties, the joining of different materials by RSW technology does not provide a quality joint, and accordingly, alternative technologies for joining different materials have emerged. Resistance element welding (REW) was developed to enable joint of different materials. This paper presents the welding of AW 5754 H22 Al alloy (1.0 mm-thick) and DP500 steel (1.5 mm-thick) using novel REW. The peak load, absorption energy, microstructure, microhardness and fatigue strength of the REW joint has been investigated. The joint of the same materials has been done also using conventional RSW to compare some results. The results that will be presented in this paper show that that REW can achieve reliable joining of the two materials at relatively low welding currents compared to RSW. Using REW process with a significantly lower welding current, satisfactory mechanical characteristics of the weld joint can be achieved, so peak load is between 2300–2500 N, displacement is between 2.5–3 mm and the absorption energy is between 3.3–5.7 J. REW joints showed fatigue strength with the fatigue limit of 882 N.
- СтавкаMicrostructure and Fatigue Properties of Resistance ElementWelded Joints of DP500 Steel and AW 5754 H22 Aluminum Alloy(MDPI, 2022) Đurić, Aleksija; Milčić, Dragan; Burzić, Zijah; Klobčar, Damjan; Milčić, Miodrag; Marković, Biljana; Krstić, VladislavThe modern concept of lightweight design (LW) requires the application of different materials in one structure (multi-material structures). The structure of different materials has a good perspective for application in the automotive and aerospace industries but only if it is possible to achieve a quality joint between different materials. The most used technology for joining different materials in the automotive industry is Resistance spot welding (RSW). Due to different mechanical, physical, and chemical properties, the joining of different materials by RSW technology does not provide a quality joint, and accordingly, alternative technologies for joining different materials have emerged. Resistance element welding (REW) was developed to enable joint of different materials. This paper presents the welding of AW 5754 H22 Al alloy (1.0 mm-thick) and DP500 steel (1.5 mm-thick) using novel REW. The peak load, absorption energy, microstructure, microhardness and fatigue strength of the REW joint has been investigated. The joint of the same materials has been done also using conventional RSW to compare some results. The results that will be presented in this paper show that that REW can achieve reliable joining of the two materials at relatively low welding currents compared to RSW. Using REW process with a significantly lower welding current, satisfactory mechanical characteristics of the weld joint can be achieved, so peak load is between 2300–2500 N, displacement is between 2.5–3 mm and the absorption energy is between 3.3–5.7 J. REW joints showed fatigue strength with the fatigue limit of 882 N.
- 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.