The modern concept of lightweight design (LW) requires the application of different materials in ... more The 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 ...
Adhesive bonding has proven to be a reliable method of joining materials, and the development of ... more Adhesive bonding has proven to be a reliable method of joining materials, and the development of new adhesives has made it possible to use bonding in a variety of applications. This article addresses the challenges of bonding metals such as the aluminum alloy EN AW-5754 and the stainless steel X5CrNi18-10. In this study, the effects of laser cleaning and texturing on the surface properties and strength of two bonded joints were investigated and compared with mechanical preparation (hand sanding with Scotch-Brite and P180 sandpaper). The bonded joints were tested with three different epoxy adhesives. During the tests, the adhesion properties of the bonded surface were determined by measuring the contact angle and assessing the wettability, the surface roughness parameters for the different surface preparations, and the mechanical properties (tensile lapshear strength). Based on the strength test results, it was found that bonded joints made of stainless steel had 16% to 40% higher strength than aluminum alloys when using the same adhesive and surface preparation. Laser cleaning resulted in maximum shear strength of the aluminum alloy bond, while the most suitable surface preparation for both materials was preparation with P180 sandpaper for all adhesives.
Computational and Experimental Approaches in Materials Science and Engineering, 2019
In contemporary machine tools as well as processing centres, threaded spindles are getting increa... more In contemporary machine tools as well as processing centres, threaded spindles are getting increasingly used. On this occasion, the higher speed of work and high accuracy of guidance are expected. Regarding this, the issue of fixing is very delicate resulting in axial angular contact ball bearings, which regarding their structure and performances, successfully meet the specified requirements. At greater work rates, there is heat load of these bearings. Due to that reason, in the designing phase, it is necessary to specify whether the temperature load shall be significant. If this is the case, the attention shall be paid to its thermal stability in the designing phase. In this paper, the experimental testing of thermal bound frequency of bearing type ZKLF, manufacturer “INA” - “Schaeffler Technologies” GmbH & Co. KG will be presented.
The modern concept of lightweight design (LW) requires the application of different materials in ... more The 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 ...
Experimental and Numerical Investigations in Materials Science and Engineering, 2018
The paper presents the results of structural and mechanical testing of the alloyed aluminum alloy... more The paper presents the results of structural and mechanical testing of the alloyed aluminum alloys AA 2024 welded by the FSW process. Investigations were conducted on the welding machine, built on the base of the conventional, vertical milling machine. The goal of the research was to know the relationship between welding parameters and mechanical and microstructural properties of 2024 joints. The following welding parameters were used: the rotation speed of the tool did not change and amounted to 750 rpm, and the welding speed was 73, 116 and 150 mm/min. The welded joints obtained were free of errors and with an acceptable flat surface.
Strojniški vestnik – Journal of Mechanical Engineering, 2021
This paper explores the influence of the frequency of shaft sleeve rotation and radial load on a ... more This paper explores the influence of the frequency of shaft sleeve rotation and radial load on a journal bearing made of tin-babbitt alloy (Tegotenax V840) under hydrodynamic lubrication conditions. An experimental test of the frictional behaviour of a radial plain bearing was performed on an originally developed device for testing rotating elements: radial and plain bearings. Using the back-propagation neural network, based on experimental data, artificial neural network models were developed to predict the dependence of the friction coefficient and bearing temperature in relation to the radial load and speed. Using experimental data of the measured friction coefficient with which the artificial neural network was trained, well-trained networks with a mean absolute percentage error on training and testing of 0.0054 % and 0.0085 %, respectively, were obtained. Thus, a well-trained neural network model can predict the friction coefficient depending on the radial load and the speed.
Physica A: Statistical Mechanics and its Applications, 2019
Abstract Rolling elements bearing are mechanical elements which should have optimal operational w... more Abstract Rolling elements bearing are mechanical elements which should have optimal operational working as long as possible. There are many influential factors which could be analyzed for the optimal operational working of the rolling elements bearing. The main aim of the study was to perform sensitivity analysis of axial rolling-element bearing by data mining algorithm. Adaptive neuro-fuzzy inference system (ANFIS) was used for the mechanical elements ranking based on their influence on the revolution of the axial rolling-element bearing. According to the results temperature of outer ring has the highest impact on the number of revolution of the bearing. The combination of friction moment and temperature of outer ring has the highest impact on the number of revolution of the bearing.
Electrical (high silicon) steels are specifically developed steels for which the principle select... more Electrical (high silicon) steels are specifically developed steels for which the principle selection principle was based on physical properties, rather than mechanical properties. Four different MAG welded joints (S355/electrical steel with 1.78 and 2.94%Si) were tested. Best result was obtained for joint 4. Furthermore, in order to decrease difference in hardness between weld metal and base metals, a change of filler material is suggested. Also, in order to reduce overlap, a smaller diameter of wire is recommended. Finally, these joints are yet to be tested on eddy current and magnetic permeability, because they affect efficiency.
In order to ensure a quality welded joint, and thus safe operation and high reliability of the we... more In order to ensure a quality welded joint, and thus safe operation and high reliability of the welded part or structure achieved by friction stir welding, it is necessary to select the optimal welding parameters. The parameters of friction stir welding significantly affect the structure of the welded joint, and thus the mechanical properties of the welded joint. Investigation of the influence of friction stir welding parameters was performed on 6-mm thick plates of aluminum alloy AA2024 T351. The quality of the welded joint is predominantly influenced by the tool rotation speed n and the welding speed v. In this research, constant tool rotation speed was adopted n = 750 rpm, and the welding speed was varied (v = 73, 116 and 150 mm/min). By the visual method and radiographic examination, imperfections of the face and roots of the welded specimens were not found. This paper presents the performed experimental tests of the macro and microstructure of welded joints, followed by tests of...
Existing standards require welded joints with full penetration. It is considered that welded join... more Existing standards require welded joints with full penetration. It is considered that welded joints with complete penetration minimize the stress concentration in the root passage. However, there are numerous situations in the industry, in which the load-bearing capacity of the welded joint with partial penetration is satisfactory. If the tests of partially penetrated welds show satisfactory load capacity, the benefits compared to fully penetrated welds are reflected in lower costs, ie less time is required to prepare the joint, less additional material is needed, ie shorter time is required to make the welded joint. The paper presents the testing of butt welded joints of structural steel S355N, with partial penetration, achieved by the MAG welding in the overhead position (PD) in the protection of the gas mixture. The samples were welded with different welding parameters and with different joint preparation, and the tests were performed by non destructive methods (visual inspection...
The aim of this study is to analyze how the process parameters affect the mechanical properties o... more The aim of this study is to analyze how the process parameters affect the mechanical properties of butt joints obtained by friction stir welding (FSW). The experimental study was performed by the FSW of sheets having a thickness equal to 6 mm and made of aluminum alloys AA2024 T351, varying the process parameters, namely rotational speed and welding speed. The following welding parameters were used: the rotation speed of the tool did not change and amounted to 750 rpm, and the welding speed was 73, 116,150 mm / min. The welds were obtained without the presence of errors and with an acceptable flat surface of the compound. Tensile tests were performed orthogonally to the welding direction on specimens having the welding nugget placed in the middle of gage length. Vickers hardness measurement was conducted perpendicular to the welding direction, a cross-section of the weld joint. The hardness profiles were obtained along 3 horizontal and 63 vertical directions. Bend testing was carrie...
An experimental research of the effect that the oil supply temperature do on the performance of a... more An experimental research of the effect that the oil supply temperature do on the performance of a 60x40x40 mm plain journal bearing is completed on the tin-based white metal material. Numerous experiments have been performed under forced lubrication; different static loads from 1045 to 3601 N and two different values of the shaft rotational speed were tested (1000 and 2000 rpm) by using the custom-built journal bearing test rig. The lubrication temperature of the bearing and the coefficient of friction vs. sliding time were measured. The realization of the frictional coefficient change is performed from the start of operation until the steady-state oil supply temperature. The results from this research demonstrate significant decreases of the frictional coefficient from startup till steady-state.
The present paper investigates experimentally the effect of sliding distance, rotation speed of s... more The present paper investigates experimentally the effect of sliding distance, rotation speed of shaft and normal load on friction, surface roughness special position on bearing inner surface and wear property of radial plain bearing made of tin-based white metal alloy-TEGOTENAX v840 under lubricated contact sliding against stainless steel shaft, to do that, a test rig apparatus was designed and fabricated. Experiments were carried out in conditions of different loads and different speed. Results show that the wear rates increase with the increase of sliding speed and normal load. It is also found that friction coefficient increases with the increase of sliding speed and decreases with increase normal load. It is also found that the roughness change with sliding distance in special position bearing inner surface.
Facta Universitatis, Series: Mechanical Engineering, 2018
A threaded gear in machine tools is a mechanical actuator that converts rotary motion into linear... more A threaded gear in machine tools is a mechanical actuator that converts rotary motion into linear one of the machine axis using a recirculating ball-nut. It provides positioning accuracy, uniform motion, silent operation, reduced wear and an increased service life. The bearing assembly of the threaded spindles should provide load transfer (cutting forces and friction forces) while maintaining high guiding accuracy. Due to a high number of the threaded spindle revolutions and the presence of tension in the bearing and a high axial force originating from the cutting and friction forces, the increased heat load due to friction in the bearings is normally expected. For this reason, this paper presents a thermal analysis of the bearing assembly of the threaded spindle which is realized via an axial ball bearing with angular contact of the ZKLN type, produced by the German manufacturer Schaeffler (INA); in other words, a numerical thermal analysis has been performed.
The modern concept of lightweight design (LW) requires the application of different materials in ... more The 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 ...
Adhesive bonding has proven to be a reliable method of joining materials, and the development of ... more Adhesive bonding has proven to be a reliable method of joining materials, and the development of new adhesives has made it possible to use bonding in a variety of applications. This article addresses the challenges of bonding metals such as the aluminum alloy EN AW-5754 and the stainless steel X5CrNi18-10. In this study, the effects of laser cleaning and texturing on the surface properties and strength of two bonded joints were investigated and compared with mechanical preparation (hand sanding with Scotch-Brite and P180 sandpaper). The bonded joints were tested with three different epoxy adhesives. During the tests, the adhesion properties of the bonded surface were determined by measuring the contact angle and assessing the wettability, the surface roughness parameters for the different surface preparations, and the mechanical properties (tensile lapshear strength). Based on the strength test results, it was found that bonded joints made of stainless steel had 16% to 40% higher strength than aluminum alloys when using the same adhesive and surface preparation. Laser cleaning resulted in maximum shear strength of the aluminum alloy bond, while the most suitable surface preparation for both materials was preparation with P180 sandpaper for all adhesives.
Computational and Experimental Approaches in Materials Science and Engineering, 2019
In contemporary machine tools as well as processing centres, threaded spindles are getting increa... more In contemporary machine tools as well as processing centres, threaded spindles are getting increasingly used. On this occasion, the higher speed of work and high accuracy of guidance are expected. Regarding this, the issue of fixing is very delicate resulting in axial angular contact ball bearings, which regarding their structure and performances, successfully meet the specified requirements. At greater work rates, there is heat load of these bearings. Due to that reason, in the designing phase, it is necessary to specify whether the temperature load shall be significant. If this is the case, the attention shall be paid to its thermal stability in the designing phase. In this paper, the experimental testing of thermal bound frequency of bearing type ZKLF, manufacturer “INA” - “Schaeffler Technologies” GmbH & Co. KG will be presented.
The modern concept of lightweight design (LW) requires the application of different materials in ... more The 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 ...
Experimental and Numerical Investigations in Materials Science and Engineering, 2018
The paper presents the results of structural and mechanical testing of the alloyed aluminum alloy... more The paper presents the results of structural and mechanical testing of the alloyed aluminum alloys AA 2024 welded by the FSW process. Investigations were conducted on the welding machine, built on the base of the conventional, vertical milling machine. The goal of the research was to know the relationship between welding parameters and mechanical and microstructural properties of 2024 joints. The following welding parameters were used: the rotation speed of the tool did not change and amounted to 750 rpm, and the welding speed was 73, 116 and 150 mm/min. The welded joints obtained were free of errors and with an acceptable flat surface.
Strojniški vestnik – Journal of Mechanical Engineering, 2021
This paper explores the influence of the frequency of shaft sleeve rotation and radial load on a ... more This paper explores the influence of the frequency of shaft sleeve rotation and radial load on a journal bearing made of tin-babbitt alloy (Tegotenax V840) under hydrodynamic lubrication conditions. An experimental test of the frictional behaviour of a radial plain bearing was performed on an originally developed device for testing rotating elements: radial and plain bearings. Using the back-propagation neural network, based on experimental data, artificial neural network models were developed to predict the dependence of the friction coefficient and bearing temperature in relation to the radial load and speed. Using experimental data of the measured friction coefficient with which the artificial neural network was trained, well-trained networks with a mean absolute percentage error on training and testing of 0.0054 % and 0.0085 %, respectively, were obtained. Thus, a well-trained neural network model can predict the friction coefficient depending on the radial load and the speed.
Physica A: Statistical Mechanics and its Applications, 2019
Abstract Rolling elements bearing are mechanical elements which should have optimal operational w... more Abstract Rolling elements bearing are mechanical elements which should have optimal operational working as long as possible. There are many influential factors which could be analyzed for the optimal operational working of the rolling elements bearing. The main aim of the study was to perform sensitivity analysis of axial rolling-element bearing by data mining algorithm. Adaptive neuro-fuzzy inference system (ANFIS) was used for the mechanical elements ranking based on their influence on the revolution of the axial rolling-element bearing. According to the results temperature of outer ring has the highest impact on the number of revolution of the bearing. The combination of friction moment and temperature of outer ring has the highest impact on the number of revolution of the bearing.
Electrical (high silicon) steels are specifically developed steels for which the principle select... more Electrical (high silicon) steels are specifically developed steels for which the principle selection principle was based on physical properties, rather than mechanical properties. Four different MAG welded joints (S355/electrical steel with 1.78 and 2.94%Si) were tested. Best result was obtained for joint 4. Furthermore, in order to decrease difference in hardness between weld metal and base metals, a change of filler material is suggested. Also, in order to reduce overlap, a smaller diameter of wire is recommended. Finally, these joints are yet to be tested on eddy current and magnetic permeability, because they affect efficiency.
In order to ensure a quality welded joint, and thus safe operation and high reliability of the we... more In order to ensure a quality welded joint, and thus safe operation and high reliability of the welded part or structure achieved by friction stir welding, it is necessary to select the optimal welding parameters. The parameters of friction stir welding significantly affect the structure of the welded joint, and thus the mechanical properties of the welded joint. Investigation of the influence of friction stir welding parameters was performed on 6-mm thick plates of aluminum alloy AA2024 T351. The quality of the welded joint is predominantly influenced by the tool rotation speed n and the welding speed v. In this research, constant tool rotation speed was adopted n = 750 rpm, and the welding speed was varied (v = 73, 116 and 150 mm/min). By the visual method and radiographic examination, imperfections of the face and roots of the welded specimens were not found. This paper presents the performed experimental tests of the macro and microstructure of welded joints, followed by tests of...
Existing standards require welded joints with full penetration. It is considered that welded join... more Existing standards require welded joints with full penetration. It is considered that welded joints with complete penetration minimize the stress concentration in the root passage. However, there are numerous situations in the industry, in which the load-bearing capacity of the welded joint with partial penetration is satisfactory. If the tests of partially penetrated welds show satisfactory load capacity, the benefits compared to fully penetrated welds are reflected in lower costs, ie less time is required to prepare the joint, less additional material is needed, ie shorter time is required to make the welded joint. The paper presents the testing of butt welded joints of structural steel S355N, with partial penetration, achieved by the MAG welding in the overhead position (PD) in the protection of the gas mixture. The samples were welded with different welding parameters and with different joint preparation, and the tests were performed by non destructive methods (visual inspection...
The aim of this study is to analyze how the process parameters affect the mechanical properties o... more The aim of this study is to analyze how the process parameters affect the mechanical properties of butt joints obtained by friction stir welding (FSW). The experimental study was performed by the FSW of sheets having a thickness equal to 6 mm and made of aluminum alloys AA2024 T351, varying the process parameters, namely rotational speed and welding speed. The following welding parameters were used: the rotation speed of the tool did not change and amounted to 750 rpm, and the welding speed was 73, 116,150 mm / min. The welds were obtained without the presence of errors and with an acceptable flat surface of the compound. Tensile tests were performed orthogonally to the welding direction on specimens having the welding nugget placed in the middle of gage length. Vickers hardness measurement was conducted perpendicular to the welding direction, a cross-section of the weld joint. The hardness profiles were obtained along 3 horizontal and 63 vertical directions. Bend testing was carrie...
An experimental research of the effect that the oil supply temperature do on the performance of a... more An experimental research of the effect that the oil supply temperature do on the performance of a 60x40x40 mm plain journal bearing is completed on the tin-based white metal material. Numerous experiments have been performed under forced lubrication; different static loads from 1045 to 3601 N and two different values of the shaft rotational speed were tested (1000 and 2000 rpm) by using the custom-built journal bearing test rig. The lubrication temperature of the bearing and the coefficient of friction vs. sliding time were measured. The realization of the frictional coefficient change is performed from the start of operation until the steady-state oil supply temperature. The results from this research demonstrate significant decreases of the frictional coefficient from startup till steady-state.
The present paper investigates experimentally the effect of sliding distance, rotation speed of s... more The present paper investigates experimentally the effect of sliding distance, rotation speed of shaft and normal load on friction, surface roughness special position on bearing inner surface and wear property of radial plain bearing made of tin-based white metal alloy-TEGOTENAX v840 under lubricated contact sliding against stainless steel shaft, to do that, a test rig apparatus was designed and fabricated. Experiments were carried out in conditions of different loads and different speed. Results show that the wear rates increase with the increase of sliding speed and normal load. It is also found that friction coefficient increases with the increase of sliding speed and decreases with increase normal load. It is also found that the roughness change with sliding distance in special position bearing inner surface.
Facta Universitatis, Series: Mechanical Engineering, 2018
A threaded gear in machine tools is a mechanical actuator that converts rotary motion into linear... more A threaded gear in machine tools is a mechanical actuator that converts rotary motion into linear one of the machine axis using a recirculating ball-nut. It provides positioning accuracy, uniform motion, silent operation, reduced wear and an increased service life. The bearing assembly of the threaded spindles should provide load transfer (cutting forces and friction forces) while maintaining high guiding accuracy. Due to a high number of the threaded spindle revolutions and the presence of tension in the bearing and a high axial force originating from the cutting and friction forces, the increased heat load due to friction in the bearings is normally expected. For this reason, this paper presents a thermal analysis of the bearing assembly of the threaded spindle which is realized via an axial ball bearing with angular contact of the ZKLN type, produced by the German manufacturer Schaeffler (INA); in other words, a numerical thermal analysis has been performed.
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