Faculty of Engineering, Kragujevac
Permanent URI for this collectionhttps://dspace.unic.kg.ac.rs/handle/123456789/8210
Since 1976, the Faculty of Mechanical Engineering from Kragujevac is a member of the University "Svetozar Markovic" of Kragujevac, now the University of Kragujevac. Since the foundation to the present, the Faculty has been intensively developing and still is developing with significant spatial, personnel and material recuperation.
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Even this small part of the achieved results shows that the Faculty of mechanical Engineering from kragujevac is an institution rich in tradition and with impressive results, recognized in domestic and foreign circles.
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Item WEAR BEHAVIOUR OF HYBRID ZA27/SIC/GRAPHITE COMPOSITES UNDER DRY SLIDING CONDITIONS(2012) Mitrovic, Slobodan; Miloradović, Nenad; Babic, Miroslav; Bobic, Ilija; Stojanovic, Blaza; Dzunic, DraganThe paper deals with tribological behaviour of hybrid composites based on ZA27 alloy reinforced with silicon-carbide (SiC) and graphite (Gr) particles. The tested sample contains 5% of SiC and 1% Gr particles. The experimental tests were performed on a “block-on-disc” tribometer. The main tribological parameter in the analysis was wear scar width, obtained by variation of normal loads and sliding speeds, under dry sliding conditions. Through observation of the changes in wear scar widths in dry sliding conditions, corresponding conclusions were made.Item Tribological Potencial of Hybrid Composites Based on Zinc ond Aluminium Alloys Reinforced with SiC and Graphite Particles(2011) Mitrovic, Slobodan; Babic, Miroslav; Stojanovic, Blaza; Miloradović, NenadThe paper reviews contemporary research in the area of hybrid composites based on zinc and aluminium alloys reinforced with SiC and graphite particles. Metal matrix composites (MMCs) based on ZA matrix are being increasingly applied as light-weight and wear resistant materials. Aluminium matrix composites with multiple reinforcements (hybrid AMCs) are finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforced composites. The results of research show that the hybrid composites possess higher hardness, higher tensile strength, better wear resistance and lower coefficient of friction when compared to pure alloys.Item Increase of life cycle due to application of welding as a surface coating method(1999) Babic, Miroslav; Mitrovic, Slobodan; Zivic, FatimaItem Design of Modern Concept Tribometer with Circular and Reciprocating Movement(2007) Marjanovic, Nenad; Tadic, Branko; Ivkovic, Branko; Mitrovic, SlobodanThis paper considers construction and advantage of modern tribometer conception. Tribometer TPD-04 enables simulation of different contact and test types. Special device enables pin on disk, circular and linear reciprocating test types. The main purpose of tribometer was investigation of friction and wear of polymer materials with or without lubricant according to appropriate standards. Tribometer concept and design solution of same subassemblies that provide defined requests fulfill were described in details. Measure system and software for data acquisition and processing results are specially described.Item Influence of Heat treatment on Tribological Behavior of Zn-Al Alloys(2007) Babic, Miroslav; Ninkovic, Rato; Mitrovic, Slobodan; Bobic, IlijaThe effects of heat treatment on the microstructure, hardness, tensile properties and tribological behavior of ZA-27 alloys in conditions of dry sliding were examined. The heat treatment of samples consisted of heating up to370 oC for 3 or 5 hours, and quenching in water. The temperature selected for solutionizing was. The heat treatment of ZA-27 alloys influences microstructure changes, decreasing of strength and hardness, but causes increasing of elongation. The rates of changes increase with increasing solutionizing duration. On the other hand, tribological tests results show that heat treatment of castings has a significant influence on improvement of their tribological properties. There, heat-treated samples casted in steel molds attained and even exceeded tribological antifriction and wear resistance behavior of sand casted samples.Item Software solution of reengineering model of technological processes of small enterprises(2011) Erić, Milan; Stefanovic, Miladin; Tadic, Branko; Mitrovic, SlobodanConstantly expanding market demands in terms of product range and product quality, price reduction and delivery times, are the basic requirements of small enterprises. How small business can respond to these requirements, or how fast, at a lower price and make the product quality, i.e. reduce the time and cost of processing, the answer is requested in the application of information technology and reengineering. The paper presents a software solution of reengineering model of technological process of small enterprises, and justification for its implementation. This solution enables reviewing the goals, minimizing time and cost of processing and maximizing productivity.Item Tribological effects of shot peening surface treatment(2008) Babic, Miroslav; Adamovic, Dragan; Jeremic B.; Mitrovic, SlobodanResults of laboratory investigations that are presented and analyzed in this paper are directly related to the tribological effects of application of the shot peening process, as the finishing machining operation. Considering the total tribological effects, one can conclude that the final machining of the contact surface by shot peening, can contribute to improvement tribological level of the tribomechanical systems elements.Item Tribological properties of composites with substrate made of the ZA-27 alloy reinforced by the graphite particles(2007) Babic, Miroslav; Mitrovic, Slobodan; Bobic, IlijaIn this paper are presented results of tribometric investigations of composites with substrate made of the ZA-27 alloy reinforced by the graphite particles of sizes 20, 35 and 100 μm in quantities of 1, 2 and 3.5 and 10 mass %. The composite materials are obtained by the compocasting procedure. Investigations were performed on the tribometer with the block-on-disc geometry in conditions with and without lubrication. Tests were done with variation of the three levels of the contact load (2 daN, 5 daN and 8 daN) and three levels of the sliding speed (0.26 m/s, 0.50 m/s and 1.00 m/s). Based on the conducted tribological investigations the optimal mass shares and particles’ sizes of the graphite reinforcer as a function of the varied parameters. Results of experimental investigations show that by the change of the mass share and particles’ sizes of graphite, one can positively influence in the sense of improving the tribological characteristics of the tested composites with the Za-27 alloy as a substrate.Item Nanotribology investigations of composites based on za-27 alloy reinforced by Al2O3 particles(2008) Mitrovic, Slobodan; Babic, Miroslav; Zivic, Fatima; Bobic, IlijaItem Influence of Heat Treatment on Tribological Properties of ZA-27 Alloy(2009) Babic, Miroslav; Mitrovic, Slobodan; Bobic, Ilija; Ninkovic, RatoItem Nanotribometer instrument as a tool for investigations in nanotribology(2008) Zivic, Fatima; Babic, Miroslav; Mitrovic, SlobodanItem ZA-27 Alloy Composites Reinforced with Al2O3 Particles(2007) Babic, Miroslav; Mitrovic, Slobodan; Bobic, IlijaThe ZA-27 alloy is present in the world as a material of very good tribological properties for the conditions of high loads and small sliding speeds. In recent years the research interest is increasing for development of the composite materials with that alloy as a substrate with addition of the Al2O3, graphite and SiC particles as the reinforcement. In this paper are presented results of tribological investigations of composites with substrate made of the ZA-27 alloy reinforced by the Al2O3 particles of sizes 12 and 250 μm in quantities of 3.5 and 10 mass %. The tribological investigations were conducted on the block-on-disc tribometer with variation of the three levels of the contact load (2 daN, 5 daN and 8 daN) and three levels of the sliding speed (0.26 m/s, 0.50 m/s and 1.00 m/s), in conditions with and without lubrication. By these tribological investigations the optimum quantity and size of the Al2O3 particles were established for obtaining the best characteristics form the aspect of wear, under the tested conditions. In all the test cases investigated composite materials possess significantly higher wear resistance than the pure metal substrate - the ZA-27 alloy.Item Corrosion Behaviour of the As-Cast and Heat-Treated Za27 Alloy(2011) Bobić B.; Mitrovic, Slobodan; Babic, Miroslav; Vencl, Aleksandar; Bobic, IlijaCorrosion behaviour of the as-cast and heat-treated ZA27 alloy was examined. The alloy was prepared by conventional melting and casting route and then thermally processed by applying T4 heat treatment regime (solutionizing at 370 C for 3 hours followed by water quenching and natural aging). Corrosion rate of the as-cast and heat-treated ZA27 alloy was determined in 3.5 wt. % NaCl solution through immersion test using both weight loss method and polarization resistance measurements. It was shown that applied thermal treatment resulted in increased ductility of the heat-treatedalloy and had a small beneficial effect on the corrosion resistance of ZA27 alloy.Item Tribological Potencial of Zinc-Aluminium Alloys Improvement(2009) Babic, Miroslav; Mitrovic, Slobodan; Ninkovic, RatoIn this paper are presented result of the study aimed at tribological improvement of ZA alloys. Two treatments of ZA-27 alloy were used: a) T4 heat treatment and b) reinforcement by graphite. The heat treatment of samples included the heating up to 370 oC for 3 or 5 hours, quenching in water and natural ageing. Graphite particles reinforced ZA-27 alloy composite materials were obtained by the compocasting procedure, which was executed by mixing at the isothermal regime (460°C). Dry and lubricated sliding wear tests were conducted on as-cast and treated ZA-27 samples using block-on-disc machine over a wide range of applied loads and sliding speed. To determine the wear mechanisms, the worn surfaces of the samples were examined by scanning electron microscopy (SEM). The heat-treated alloy samples as well as reinforced samples attained significantly improved tribological behavior over the as-cast ones, both from the aspects of friction and wear.Item Wear Properties Of Shot Peened Surfaces Of 36NiCrMo16 Alloyed Steels Under Lubricated Condition(2011) Babic, Miroslav; Adamovic, Dragan; Mitrovic, Slobodan; Zivic, Fatima; Dzunic, Dragan; Pantić, MarkoItem Virtual Simulation of a Guiding System for Eccentrically Loaded Slide Ways(2004) Mitrovic, SlobodanProper selection of slide ways of machine tools has the exceptional influence on machining precision and quality of the machine surface. All errors that arose as a consequence of clearance between the sliding surfaces or deformations in the contact zone directly affect the machining error. In order to ensure mobility of slide ways, it is necessary that a clearance exist in sliding joints. Under the influence of eccentric load the twisting of the cross section of the slide way occurs, which can lead to appearance of self-braking, namely the blocking of slider's motion along the slide ways. To prevent that it is necessary that the length of a slider is as large as possible with respect to its width. Since the increase in size of the stand also leads to increase of the slide ways, the whole machine, and by that also its weight and price, that solution of this problem requires more complex analysis, especially from the tribological aspect. This paper presents an attempt of solving the undesired effect of slide ways self-braking. Through theoretical analyses.Item Tribological Properties of Shot Peened Surfaces of 36NiCrMo16 Alloyed Steels in Dry Sliding Condition(2011) Babic, Miroslav; Adamovic, Dragan; Mitrovic, Slobodan; Zivic, Fatima; Dzunic, Dragan; Pantić, MarkoFor right choice of final operation procession, in tribological sense, it is necessary to know the legality of manifesting influences of certain types of processing, as well as regime parameters and conditions of their performance on relevant surface topography parameters (height, cloud, and micro-geometry structure), physical-mechanical state and residual voltages of surface layer. Shot peening method is used to increase both statics, and dynamics hardness of work piece. The result of this method is not only surface layer characteristic change of certain piece but also tribological characteristics change of such processed piece. The results of laboratory tests, which correspond and analyse together in work, refer to effects of shot peening use, as final processing by surface plastic deforming, in the example of alloyed steel 36NiCrMo16,with their tribological valorisation of friction and wear tests. Tribological studies show that overall effects of final shot peening processing have positive effect on tribological behaviour of processed elements and may contribute to improvement of tribological element level of tribomechanical systems.Item Wear Behaviour of TiN Coatings for Cold Forming Tools under Dry Sliding Conditions(2011) Mitrovic, Slobodan; Babic, Miroslav; Adamovic, Dragan; Zivic, Fatima; Dzunic, Dragan; Pantić, MarkoTiN coatings are very common themes of scientific works and are largely used in industry in metal cutting and cold forming processes; This work on quantitative way represents improvement, in terms of wear resistance, which is obtained by depositing of PVD TiN coating on foundation material. Wear testing is done on tribometer with block –on –disc contact geometry at sliding sample contact coated by TiN coat with steel disc. Testing was performed in conditions without lubrication at variable value of contact parameters (normal load, sliding speed). PVD TiN coatings in all contact conditions show smaller values of wear degree.Item WEAR AND FRICTION PROPERTIES OF SHOT PEENED SURFACES OF 36CRNIMO4 AND 36NICRMO16 ALLOYED STEELS UNDER DRY AND LUBRICATED CONTACT CONDITIONS(2012) Mitrovic, Slobodan; Babic, Miroslav; Adamovic, Dragan; Zivic, Fatima; Dzunic, Dragan; Pantić, MarkoMethod of Shot peening is often used to increase static and dynamic strength of the work piece. This method can change the characteristics of the surface layer, and thus the tribological properties of such treated surfaces. The quality of the contact surfaces in tribological terms, refers to the roughness parameters and surface microgeometry. Conclusions, presented in this paper, are the result of numerous investigations of tribological behavior of shot peening surfaces in dry and lubricated contact conditions. As materials for tribological tests 36CrNiMo4 and 36NiCrMo16 alloy steels were used. The paper presents a comparative view of tribological behavior of materials under conditions with and without lubrication, as well as in terms of different values of normal load and sliding velocity. Tribological investigations showed that total effects of final machining by shot peening have positive influence on tribological behaviour of machined parts and that they can contribute to the improvement of tribological level of tribomechanical elements.Item Tribology in Biomaterials Design and Selection(2011) Zivic, Fatima; Babic, Miroslav; Mitrovic, Slobodan; Adamovic, Dragan; Grujovic, NenadThe paper presents review of selected biomaterials that were subject of tribological investigations at Tribology Center of Mechanical Engineering Faculty Kragujevac. Development, design and selection of biomaterials are primary determined by characteristics and nature of the tissue that is being replaced or supplemented. Modern material investigations at micro level loads enable insight into new aspects of material behaviour and offer possibilities for further improvement. Tribological investigations of biomaterials can contribute to their development by offering solutions for wear decrease and wear prediction. Short review is presented of tribological tests of four different biomaterials, namely Ti6Al4V alloy, stainless steel AISI 316LVM, ultrahigh-molecular-weight polyethylene (UHMWPE) and polymethyl methacrylate (PMMA).