This page has only limited features, please log in for full access.
Plain bearings are undoubtedly one of the main parts of the power machines (such as a turbine or compressor). However, there are many cases when in large power equipment is occurring asymmetrically loading on bearings due to thermal deformations, production inaccuracies, or simple deflection of the shaft. Presented research deals with the numerical analysis of levers being as the first step at the design of a new self-equalizing thrust bearing with the goal to find out its behaviour and base on that to make the improvements. The numerical analysis was done for the bearing with 12 segments using the software ANSYS. The boundary conditions were applied so to prevent the movement (collapse) of the system and at the same time use them to influence the stress distribution in the levers as little as possible. The steel 34CrNiMo6 has been used for the levers in a refined state. The achieved results confirmed the design of the levers, its sufficient stiffness, good functionality, and reliability.
Katarina Monkova; Marek Urban; Peter Pavol Monka; Stefan Moravka; Željko Božić. Design of the levers at the development of new self-equalizing thrust bearings. Procedia Structural Integrity 2021, 31, 92 -97.
AMA StyleKatarina Monkova, Marek Urban, Peter Pavol Monka, Stefan Moravka, Željko Božić. Design of the levers at the development of new self-equalizing thrust bearings. Procedia Structural Integrity. 2021; 31 ():92-97.
Chicago/Turabian StyleKatarina Monkova; Marek Urban; Peter Pavol Monka; Stefan Moravka; Željko Božić. 2021. "Design of the levers at the development of new self-equalizing thrust bearings." Procedia Structural Integrity 31, no. : 92-97.
Hydrodynamic thrust bearings are generally used to absorb axial forces in machinery, especially where the use of rolling bearings is inappropriate in terms of dimensional constraints, service life, high loads or difficult access during assembly. Misalignment between the stator and the rotor, especially on large rotary machines, can lead to a reduction in the load capacity and damage to the entire device. To eliminate misalignment between stator and rotor (especially in large rotary machines) the thrust bearing with a system of very precise manufactured levers has started to be used. The article deals with the study of the influence of surface treatment on the development of wear and damage under quasi-static loading of the levers, which are critical parts of a newly designed axial bearing. The presented research has been carried out in two phases. In the first phase, basic samples that represented the types of geometries coming into contact in real conditions of bearing operation were manufactured and experimentally tested. Based on the results obtained at this stage, it was found that electroless nickel-plated samples showed the best results in terms of surface treatment. Due to this, real levers were produced in three sizes, which are estimated to have the potential for the greatest use in turbines, and these were surface treated with electroless nickel plating. In the second phase, the surface integrity and stiffness of the levers were examined. All samples and levers were made of 34CrNiMo6 steel. The evaluation was performed using stereomicroscope and a scanning electron microscope. Based on the results, it could be stated that the integrity of the surface was not significantly violated in any simple sample or lever. Thus, the tests confirmed the suitability of the proposed method of surface treatment of levers and their sufficient rigidity under quasi-static static loading.
Katarina Monkova; Marek Urban; Peter Pavol Monka; Drazan Kozak. Study of the influence of surface treatment on the wear development under quasi-static loading of the levers of a newly designed thrust bearing. Engineering Failure Analysis 2021, 124, 105383 .
AMA StyleKatarina Monkova, Marek Urban, Peter Pavol Monka, Drazan Kozak. Study of the influence of surface treatment on the wear development under quasi-static loading of the levers of a newly designed thrust bearing. Engineering Failure Analysis. 2021; 124 ():105383.
Chicago/Turabian StyleKatarina Monkova; Marek Urban; Peter Pavol Monka; Drazan Kozak. 2021. "Study of the influence of surface treatment on the wear development under quasi-static loading of the levers of a newly designed thrust bearing." Engineering Failure Analysis 124, no. : 105383.
The development of additive technology has made it possible to produce metamaterials with a regularly recurring structure, the properties of which can be controlled, predicted, and purposefully implemented into the core of components used in various industries. Therefore, knowing the properties and behavior of these structures is a very important aspect in their application in real practice from the aspects of safety and operational reliability. This article deals with the effect of cell size and volume ratio of a body-centered cubic (BCC) lattice structure made from Acrylonitrile Butadiene Styrene (ABS) plastic on mechanical vibration damping and compression properties. The samples were produced in three sizes of a basic cell and three volume ratios by the fused deposition modeling (FDM) technique. Vibration damping properties of the tested 3D-printed ABS samples were investigated under harmonic excitation at three employed inertial masses. The metamaterial behavior and response under compressive loading were studied under a uniaxial full range (up to failure) quasi-static compression test. Based on the experimental data, a correlation between the investigated ABS samples’ stiffness evaluated through both compressive stress and mechanical vibration damping can be found.
Katarina Monkova; Martin Vasina; Milan Zaludek; Peter Monka; Jozef Tkac. Mechanical Vibration Damping and Compression Properties of a Lattice Structure. Materials 2021, 14, 1502 .
AMA StyleKatarina Monkova, Martin Vasina, Milan Zaludek, Peter Monka, Jozef Tkac. Mechanical Vibration Damping and Compression Properties of a Lattice Structure. Materials. 2021; 14 (6):1502.
Chicago/Turabian StyleKatarina Monkova; Martin Vasina; Milan Zaludek; Peter Monka; Jozef Tkac. 2021. "Mechanical Vibration Damping and Compression Properties of a Lattice Structure." Materials 14, no. 6: 1502.
The disintegration of material surface exposed to pulsating water jet depends upon the technological parameters as well as interacting surface properties. Surface modified by various machining operations results in the generation of different surface roughness. These differences in surface asperities cause variation in the shear stress-induced into the material during the lateral jetting phase of the water hammer phenomenon. Therefore, in the present study influence of different modified surfaces (0A, 1A, 2A, 3A and 4A) and variation in standoff distance (z = 1 to 57 mm) on material erosion in terms of disintegration depth is studied. The surfaces are modified using milling operation with variation in tool diameter, cutting speed and number of tool inserts. The result shows a bell curve pattern of disintegration depth with increasing standoff distance. The maximal disintegration depth of the samples varied from hmax = 523 to 773 µm depending upon the surface finish with minimum maximal depth (hmax = 523 µm) observed for the polished sample.
Ashokkumar Ravichandiran; Peter Pavol Monka; Katarína Monková; Monika Hromasova. Effect of Surface Modification and Standoff Distance on Hydrodynamic Ductile Erosion. Recent Advances in Computational Mechanics and Simulations 2021, 111 -119.
AMA StyleAshokkumar Ravichandiran, Peter Pavol Monka, Katarína Monková, Monika Hromasova. Effect of Surface Modification and Standoff Distance on Hydrodynamic Ductile Erosion. Recent Advances in Computational Mechanics and Simulations. 2021; ():111-119.
Chicago/Turabian StyleAshokkumar Ravichandiran; Peter Pavol Monka; Katarína Monková; Monika Hromasova. 2021. "Effect of Surface Modification and Standoff Distance on Hydrodynamic Ductile Erosion." Recent Advances in Computational Mechanics and Simulations , no. : 111-119.
To eliminate misalignment between stator and rotor (especially in large rotary machines) the thrust bearing with a system of very precise manufactured levers has started to be used. The article deals with the static tests of self-equalizing elements (levers) made of 34CrNiMo6 steel, which are the critical parts of a newly developing self-equalizing thrust bearing. To verify the stiffness of the newly designed levers by static tests, the real levers were produced, which according to preliminary experiments and numerical simulations have the potential to be used the most in turbines. Based on basic tests of the pairs samples, that represent types of geometries going in contact within real conditions, it was found out that in terms of the surface treatment, the best results show electroless nickel-plated samples. So, due to this reason, the real levers were produced and their surfaces were processed in this way by electroless nickel-plating. Within the presented research, they were statically tested intending to determine the surface integrity and whether there was any development of damage to the surface layer. The evaluation was done using a stereomicroscope and a scanning electron microscope. The tests confirm sufficient rigidity of the levers including a suitable method of surface processing. Although, in some cases, these were surface defects caused by surface treatment technology, but no defects were found after static loading.
Katarina Monkova; Marek Urban; Peter Monka; Drazan Kozak. Verification of stiffness and surface treatment of axial bearing levers by static tests. Procedia Structural Integrity 2020, 28, 776 -783.
AMA StyleKatarina Monkova, Marek Urban, Peter Monka, Drazan Kozak. Verification of stiffness and surface treatment of axial bearing levers by static tests. Procedia Structural Integrity. 2020; 28 ():776-783.
Chicago/Turabian StyleKatarina Monkova; Marek Urban; Peter Monka; Drazan Kozak. 2020. "Verification of stiffness and surface treatment of axial bearing levers by static tests." Procedia Structural Integrity 28, no. : 776-783.
The article deals with the specification of the most suitable machining parameters for three newly designed end mills in the term of stability of the deep groove machining, at which the depth of cut is minimally twice higher the diameter of the cutter. Online vibration analysis was selected as a tool for goal achievement. The partial objective of the first phase of experimental research was to set the boundary conditions of vibrodiagnostics at the specification of the behaviour of three commercially produced milling cutters when the results were compared with the surface roughness achieved at the machining with individual cutting parameters. Vibrodiagnostic conditions were subsequently applied in the second phase of the experiment to determine the most suitable machining parameters of newly designed milling cutters. The Pinnacle VMC 650 CNC machining centre with Fanuc control system was used to perform the experiments. The material of cutters was S-grade sintered carbide, and all the designed cutters were PVD coated with the same AlTiN (aluminium titanium nitride) coating. The machined material was 16MnCr5 (1.7131) steel. The surface roughness analysis after machining by newly designed cutters pointed out that they are better as for the surface quality in comparison with the commercially produced end mills. Finally, it was possible to state that the four-tooth cutter 01-FVT with helix angles (β1 = 39° and β2 = 41°) and tooth pitch (τ1 = 83° and τ2 = 97°) seems to be the best tool for milling deep-shaped grooves among all the tested milling cutters.
Peter Pavol Monka; Katarina Monkova; Vidosav D. Majstorovic; Željko Božić; Andrej Andrej. Optimal cutting parameter specification of newly designed milling tools based on the frequency monitoring. The International Journal of Advanced Manufacturing Technology 2020, 1 -18.
AMA StylePeter Pavol Monka, Katarina Monkova, Vidosav D. Majstorovic, Željko Božić, Andrej Andrej. Optimal cutting parameter specification of newly designed milling tools based on the frequency monitoring. The International Journal of Advanced Manufacturing Technology. 2020; ():1-18.
Chicago/Turabian StylePeter Pavol Monka; Katarina Monkova; Vidosav D. Majstorovic; Željko Božić; Andrej Andrej. 2020. "Optimal cutting parameter specification of newly designed milling tools based on the frequency monitoring." The International Journal of Advanced Manufacturing Technology , no. : 1-18.
Noise has a negative impact on our environment and human health. For this reason, it is necessary to eliminate excessive noise levels. This paper is focused on the study of the sound absorption properties of materials with open-porous structures, which were made of acrylonitrile butadiene styrene (ABS) material using additive technology. Four types of structures (Cartesian, octagonal, rhomboid, and Starlit) were evaluated in this work, and every structure was prepared in three different volume ratios of the porosity and three different thicknesses. The sound absorption properties of the investigated ABS specimens were examined utilizing the normal incidence sound absorption and noise reduction coefficients, which were experimentally determined by the transfer function method using a two-microphone acoustic impedance tube. This work deals with various factors that influence the sound absorption performance of four different types of investigated ABS material’s structures. It was found, in this study, that the sound absorption performance of the investigated ABS specimens is strongly affected by different factors, specifically by the structure geometry, material volume ratio, excitation frequency of an acoustic wave, material´s thickness, and air space size behind the tested sound-absorbing materials.
Katarina Monkova; Martin Vasina; Peter Pavol Monka; Drazan Kozak; Jan Vanca. Effect of the Pore Shape and Size of 3D-Printed Open-Porous ABS Materials on Sound Absorption Performance. Materials 2020, 13, 4474 .
AMA StyleKatarina Monkova, Martin Vasina, Peter Pavol Monka, Drazan Kozak, Jan Vanca. Effect of the Pore Shape and Size of 3D-Printed Open-Porous ABS Materials on Sound Absorption Performance. Materials. 2020; 13 (20):4474.
Chicago/Turabian StyleKatarina Monkova; Martin Vasina; Peter Pavol Monka; Drazan Kozak; Jan Vanca. 2020. "Effect of the Pore Shape and Size of 3D-Printed Open-Porous ABS Materials on Sound Absorption Performance." Materials 13, no. 20: 4474.
By inspecting the existing constructional designs of boat cranes and the requirements which need to be fulfilled, the new constructional design of the boat crane is made. After determining the critical position of the crane in the form of a load, calculation of the inside diameters of cylinders is made and optimized depending on the maximum axial force. Numeric calculation of the stresses and total deformations in software ANSYS Workbench has proved that the design of crane has met all the requirements imposed on the strength. After designing the boat crane and preforming the strength calculations, it is necessary to analyze the motion of the designed crane construction. Boat crane is designed with hydraulic cylinders and rotation around the shaft using a hydraulic motor. Therefore, it is necessary to create a scheme of a hydraulic system of the crane. During the designing and strength analysis, no material exploitation was taken into account and reinforcements were added only to reduce the equivalent stresses and the maximum total deformation of the crane. Due to the possible oversizing of the reinforcements, the optimization was performed by the response surface optimization method. Optimization was performed to minimize the mass and it has been found that the construction was oversized and the mass was reduced by almost 14 kg.
Janko Morosavljević; Dražan Kozak; Katarina Monkova; Darko Damjanović. Strength Calculation and Optimization of Boat Crane. Inventive Computation and Information Technologies 2020, 35 -52.
AMA StyleJanko Morosavljević, Dražan Kozak, Katarina Monkova, Darko Damjanović. Strength Calculation and Optimization of Boat Crane. Inventive Computation and Information Technologies. 2020; ():35-52.
Chicago/Turabian StyleJanko Morosavljević; Dražan Kozak; Katarina Monkova; Darko Damjanović. 2020. "Strength Calculation and Optimization of Boat Crane." Inventive Computation and Information Technologies , no. : 35-52.
The article deals with the simulation of real technological process using the computer technology to optimize the flexible manufacturing system (FMS). There was created a simulation model of the FMS for time-saving modelling of production aimed at the utilization of the system capacities for reaching the higher level of efficiency respecting delivery dates. The simulations provided a lot of other useful information describes the properties of the FMS in details. The most used information for the producer was time data (cycle, processing, waiting, lateness, etc.). A wide variation of clamping fixtures and missing buffers between CNC machines were the most problematic issues of the system, generally. Experimental verifications of the FMS confirmed the advantage of using an industrial simulation to verify different production strategies.
Peter Pavol Monka; Katarina Monkova; Andrej Jahnátek; Ján Vanca. Flexible Manufacturing System Simulation and Optimization. Inventive Computation and Information Technologies 2020, 53 -64.
AMA StylePeter Pavol Monka, Katarina Monkova, Andrej Jahnátek, Ján Vanca. Flexible Manufacturing System Simulation and Optimization. Inventive Computation and Information Technologies. 2020; ():53-64.
Chicago/Turabian StylePeter Pavol Monka; Katarina Monkova; Andrej Jahnátek; Ján Vanca. 2020. "Flexible Manufacturing System Simulation and Optimization." Inventive Computation and Information Technologies , no. : 53-64.
One of the common problems of organizations with turn-key projects is the high scrap rate. There exist such traditional methods as Lean Six Sigma (LSS) and DMAIC tools that analyze causes and suggest solutions. New emerging intelligent technologies should influence these methods and tools as they affect many areas of our life. The purpose of this paper is to present the innovative Lean Six Sigma method for the Small Mixed Bathes (SMB) production system. The standard set of LSS tools is extended by intelligent technologies such as artificial neural networks (ANN) and machine learning. The proposed method uses the data-driven quality strategy to improve the turning process at the bakery machine manufacturer. The case study shows the step-by-step DMAIC procedure of critical to quality (CTQ) characteristics improvement. Findings from the data analysis lead to a change of measurement instrument, training of operators, and lathe machine set-up correction. However, the scrap rate did not decrease significantly. Therefore the advanced mathematical model based on ANN was built. This model predicts the CTQ characteristics from the inspection certificate of the input material. The prediction model is a part of a newly designed process control scheme using machine learning algorithms to reduce the variability even for input material with different properties from new suppliers. Further research will be focused on the validation of the proposed control scheme, and acquired experiences will be used to support business sustainability.
Kristina Zgodavova; Peter Bober; Vidosav Majstorovic; Katarina Monkova; Gilberto Santos; Darina Juhaszova. Innovative Methods for Small Mixed Batches Production System Improvement: The Case of a Bakery Machine Manufacturer. Sustainability 2020, 12, 6266 .
AMA StyleKristina Zgodavova, Peter Bober, Vidosav Majstorovic, Katarina Monkova, Gilberto Santos, Darina Juhaszova. Innovative Methods for Small Mixed Batches Production System Improvement: The Case of a Bakery Machine Manufacturer. Sustainability. 2020; 12 (15):6266.
Chicago/Turabian StyleKristina Zgodavova; Peter Bober; Vidosav Majstorovic; Katarina Monkova; Gilberto Santos; Darina Juhaszova. 2020. "Innovative Methods for Small Mixed Batches Production System Improvement: The Case of a Bakery Machine Manufacturer." Sustainability 12, no. 15: 6266.
An additive technology can produce complex geometries which might not have been possible to produce using traditional manufacturing techniques. One such geometry is a lattice structure that can lighten the core of a component. The article deals with the investigation of tensile properties of the samples made from ABS (Acrylonitrile Butadiene Styrene) material. Two types of cylindrical lightened samples (with a simple lattice structure and in the form of a tube) were analyzed experimentally. FDM (Fused Deposition modelling) technique and filament of a 1.7 mm diameter were selected for the samples production. The results showed that at almost the same cross-section area of the samples, the lattice structure can carry a higher tensile yield strength compared with a shelled tube sample.
Katarina Monkova; Peter Pavol Monka; Jan Vanca; Milan Zaludek; Oldrich Suba. Tensile Behaviour of a 3D Printed Lattice Structure. 2020 11th International Conference on Mechanical and Aerospace Engineering (ICMAE) 2020, 22 -26.
AMA StyleKatarina Monkova, Peter Pavol Monka, Jan Vanca, Milan Zaludek, Oldrich Suba. Tensile Behaviour of a 3D Printed Lattice Structure. 2020 11th International Conference on Mechanical and Aerospace Engineering (ICMAE). 2020; ():22-26.
Chicago/Turabian StyleKatarina Monkova; Peter Pavol Monka; Jan Vanca; Milan Zaludek; Oldrich Suba. 2020. "Tensile Behaviour of a 3D Printed Lattice Structure." 2020 11th International Conference on Mechanical and Aerospace Engineering (ICMAE) , no. : 22-26.
With Industry 4.0, additive-manufacturing methods will be widely used to produce small batches of customized products that offer construction advantages, such as complex, lightweight designs. One type of products that belong to the sophisticated components, producible by 3D printing technology, is a lattice structure. The article deals with the three points bending test of the cylindrical samples. FDM (Fused Deposition modelling) technique and ABS (Acrylonitrile Butadiene Styrene) material were selected for the samples production. Two types of samples (with a simple lattice structure and fully filled by material) were analyzed experimentally and numerically. The results showed that in spite of the material saving at the porous structure production, the lattice structure with body-centred cube cell is not very suitable for the components loaded by bending, because a unit of material at this type of sample is able to carry down less stress compared to the sample fully filled by the material.
Katarina Monkova; Peter Pavol Monka; Jozef Tkac; Jan Vanca. A Bending Test of the Additively Produced Porous Sample. Recent Advances in Computational Mechanics and Simulations 2020, 59 -68.
AMA StyleKatarina Monkova, Peter Pavol Monka, Jozef Tkac, Jan Vanca. A Bending Test of the Additively Produced Porous Sample. Recent Advances in Computational Mechanics and Simulations. 2020; ():59-68.
Chicago/Turabian StyleKatarina Monkova; Peter Pavol Monka; Jozef Tkac; Jan Vanca. 2020. "A Bending Test of the Additively Produced Porous Sample." Recent Advances in Computational Mechanics and Simulations , no. : 59-68.
Noise pollution is a negative factor that affects our environment. It is, therefore, necessary to take appropriate measures to minimize it. This article deals with the sound absorption properties of open-porous Acrylonitrile Butadiene Styrene (ABS) material structures that were produced using 3D printing technology. The material’s ability to damp sound was evaluated based on the normal incidence sound absorption coefficient and the noise reduction coefficient, which were experimentally measured by the transfer function method using an acoustic impedance tube. The different factors that affect the sound absorption behavior of the studied ABS specimens are presented in this work. In this study, it was discovered that the sound absorption properties of the tested ABS samples are significantly influenced by many factors, namely by the type of 3D-printed, open-porous material structure, the excitation frequency, the sample thickness, and the air gap size behind the sound-absorbing materials inside the acoustic impedance tube.
Martin Vasina; Katarina Monkova; Peter Pavol Monka; Drazan Kozak; Jozef Tkac. Study of the Sound Absorption Properties of 3D-Printed Open-Porous ABS Material Structures. Polymers 2020, 12, 1062 .
AMA StyleMartin Vasina, Katarina Monkova, Peter Pavol Monka, Drazan Kozak, Jozef Tkac. Study of the Sound Absorption Properties of 3D-Printed Open-Porous ABS Material Structures. Polymers. 2020; 12 (5):1062.
Chicago/Turabian StyleMartin Vasina; Katarina Monkova; Peter Pavol Monka; Drazan Kozak; Jozef Tkac. 2020. "Study of the Sound Absorption Properties of 3D-Printed Open-Porous ABS Material Structures." Polymers 12, no. 5: 1062.
Mechanical characteristics of 3D printed lattice structures primarily depend on the properties of materials from which they are produced. Another factor is the topology of the structure. In the paper it was shown, that the behavior of the lattice can significantly differ from the fully-dense material and both the experiments and the FE modelling is necessary to describe well the structure in the macroscopic sense. A separate problem is damage identification along with the process of deformation – this however can be done with satisfactory effect by treating the lattice as a porous structure. For creating the 3D model of the lattice/porous structure the PTC Creo 6 CAD software was used. It enabled both physical realization of the porous ABS specimens and exporting the geometry to the FE software environment Abaqus. The performed experimental tests of uniaxial compression enabled determination of the material model necessary to be implemented in the numerical simulations. The macroscopic damage initiation and its evolution was described well with a scalar damage parameter. The proposed procedure might be accepted as a simple and easy-to-implement methodology for the assessment of the lattice/porous material deterioration.
Jozef Tkac; Sylwester Samborski; Katarina Monkova; Hubert Debski. Analysis of mechanical properties of a lattice structure produced with the additive technology. Composite Structures 2020, 242, 112138 .
AMA StyleJozef Tkac, Sylwester Samborski, Katarina Monkova, Hubert Debski. Analysis of mechanical properties of a lattice structure produced with the additive technology. Composite Structures. 2020; 242 ():112138.
Chicago/Turabian StyleJozef Tkac; Sylwester Samborski; Katarina Monkova; Hubert Debski. 2020. "Analysis of mechanical properties of a lattice structure produced with the additive technology." Composite Structures 242, no. : 112138.
This chapter deals with the analytic network process as a tool of innovative management at manufacturing technology selection. It is a multi-criteria analysis at which the most appropriate method is nominated within given conditions. In the presented research, nine unconventional methods dedicated for the disintegration of special composite material have been considered. Special features of these advanced methods are defined in this chapter, as well as a sequence of steps used in analytic network process related to the technology choice. Firstly, a hierarchical structure of individual technologies with their criteria and sub-criteria has been prepared and they have been pairwise compared. Final values have been recalculated using the degrees of importance and final weights, while the resulting matrix has been developed. The interdependencies and linkages between the various criteria of each technology have also been described in the manuscript. Results have shown that the most suitable method for cutting of investigated composite material appears to be the technology of pulsating water jet.
Peter Monka; Katarina Monkova; Andrej Andrej; Jozef Tkac; Vladimir Duchek; Milan Edl; Helena Zidkova. Analytic Network Process as a Tool of Innovative Management at Manufacturing Technology Selection. Advanced Controllers for Smart Cities 2020, 539 -547.
AMA StylePeter Monka, Katarina Monkova, Andrej Andrej, Jozef Tkac, Vladimir Duchek, Milan Edl, Helena Zidkova. Analytic Network Process as a Tool of Innovative Management at Manufacturing Technology Selection. Advanced Controllers for Smart Cities. 2020; ():539-547.
Chicago/Turabian StylePeter Monka; Katarina Monkova; Andrej Andrej; Jozef Tkac; Vladimir Duchek; Milan Edl; Helena Zidkova. 2020. "Analytic Network Process as a Tool of Innovative Management at Manufacturing Technology Selection." Advanced Controllers for Smart Cities , no. : 539-547.
There are many cases when in large power equipment (such as a turbine or compressor) asymmetrically loading on bearings due to thermal deformations, production inaccuracies, or simple deflection of the shaft occurs. This asymmetrically loading means misalignment of rotor against stator in angle more than several tenths of a degree and it has an influence on a journal and thrust bearings. Over the last few years, thanks to increasingly precise manufacturing, solutions that can eliminate this phenomenon have been revealed. In the case of the thrust bearing, it is a system of very precise manufactured levers, which are in close contact each to other, so they have to be not only properly designed from the geometrical point of view but the important role plays a quality of the functional surfaces of these levers. The article deals with the surface treatment effect on tribological properties of 34CrNiMo6 steel used for the production of bearing levers, which are the critical parts of a newly developing self-equalizing thrust bearing. The samples with cylindrical and plate shapes were produced from 34CrNiMo6 steel as representatives of the most suitable geometries for contact surfaces. All samples were heat-treated. The surfaces of some samples were treated by electroless nickel plating or nitriding, some of the samples were treated by tumbling. Gradually, the surface roughness, microhardness, metallographic analysis and the influence of selected types of surface treatments on the wear for individual samples were evaluated within the research presented in the article. As the testing methods for evaluation of tribological properties were selected Pin-on-disc test and frequency tribological test. The results showed that the best tribological properties achieved samples treated by electroless nickel plating compared with the nitrided or only heat-treated samples.
Marek Urban; Katarina Monkova. Research of Tribological Properties of 34CrNiMo6 Steel in the Production of a Newly Designed Self-Equalizing Thrust Bearing. Metals 2020, 10, 84 .
AMA StyleMarek Urban, Katarina Monkova. Research of Tribological Properties of 34CrNiMo6 Steel in the Production of a Newly Designed Self-Equalizing Thrust Bearing. Metals. 2020; 10 (1):84.
Chicago/Turabian StyleMarek Urban; Katarina Monkova. 2020. "Research of Tribological Properties of 34CrNiMo6 Steel in the Production of a Newly Designed Self-Equalizing Thrust Bearing." Metals 10, no. 1: 84.
Katarina Monkova; Peter P. Monka. Three Views on Kinematic Analysis of Whitworth Mechanism of a Shaping Machine. International Journal of Mechanical Engineering and Robotics Research 2020, 1 .
AMA StyleKatarina Monkova, Peter P. Monka. Three Views on Kinematic Analysis of Whitworth Mechanism of a Shaping Machine. International Journal of Mechanical Engineering and Robotics Research. 2020; ():1.
Chicago/Turabian StyleKatarina Monkova; Peter P. Monka. 2020. "Three Views on Kinematic Analysis of Whitworth Mechanism of a Shaping Machine." International Journal of Mechanical Engineering and Robotics Research , no. : 1.
Katarina Monkova; Peter P. Monka; Slavomir Hric; Drazan Kozak; Marko Katinić; Ivan Pavlenko; Oleksandr Liaposchenko. Condition Monitoring of Kaplan Turbine Bearings Using Vibro-diagnostics. International Journal of Mechanical Engineering and Robotics Research 2020, 1 .
AMA StyleKatarina Monkova, Peter P. Monka, Slavomir Hric, Drazan Kozak, Marko Katinić, Ivan Pavlenko, Oleksandr Liaposchenko. Condition Monitoring of Kaplan Turbine Bearings Using Vibro-diagnostics. International Journal of Mechanical Engineering and Robotics Research. 2020; ():1.
Chicago/Turabian StyleKatarina Monkova; Peter P. Monka; Slavomir Hric; Drazan Kozak; Marko Katinić; Ivan Pavlenko; Oleksandr Liaposchenko. 2020. "Condition Monitoring of Kaplan Turbine Bearings Using Vibro-diagnostics." International Journal of Mechanical Engineering and Robotics Research , no. : 1.
Tool durability is an important parameter in the evaluation of the performance of the cutting tools and inserts. It is directly connected with tool wear that significantly affects the quality of the workpiece. Only from an understanding of the nature behind the machining process in given conditions (a combination of cutting parameters, machined material, tool characteristics including its material, etc.), a tool wear mechanism can be identified and consequently estimate the tool life and its durability. The article deals with a durability of the milling cutters produced from the high-speed steel via powder metallurgy (HSS-PM) and coated by AlTiN coat. Effects of a varying combination of cutting speed and depth of cut to tool wear and surface roughness had been also investigated within the long-term tests. Conventional milling was selected as a technology to test the durability of HSSE-PM shank milling cutters at which the steel 1.4301 (AISI 304, DIN 1.4301) as a material that is very difficult to cut was machined without a coolant. Within the research, the tool wears in several points on a cutting edge were evaluated, while several types of tool wear have been identified. Achieved data were statistically processed and based on them the development of the tool wear of individual milling cutters in time has been processed as well as a dependency of the tool wear on cutting speed and cutting depth has been plotted. The accompanying phenomenon of tool wear increasing is a deteriorated quality of surface roughness and change in a chip formation. The average values of surface roughness Ra relative to machining time achieved by milling cutters working at a specific depth of cut were also assessed. The pictures of the chips approved that along with tool wear increasing the chip becomes thinner with larger rugged relief.
Katarina Monkova; Shufeng Sun; Peter Pavol Monka; Sergej Hloch; Miroslav Belan. Durability and tool wear investigation of HSSE-PM milling cutters within long-term tests. Engineering Failure Analysis 2019, 108, 104348 .
AMA StyleKatarina Monkova, Shufeng Sun, Peter Pavol Monka, Sergej Hloch, Miroslav Belan. Durability and tool wear investigation of HSSE-PM milling cutters within long-term tests. Engineering Failure Analysis. 2019; 108 ():104348.
Chicago/Turabian StyleKatarina Monkova; Shufeng Sun; Peter Pavol Monka; Sergej Hloch; Miroslav Belan. 2019. "Durability and tool wear investigation of HSSE-PM milling cutters within long-term tests." Engineering Failure Analysis 108, no. : 104348.
The paper deals with the influence of gear weight reduction on its modal properties. The aim of thepaper is to use the simulation tools to introduce the dependence of natural frequencies on the change in the shape of the gear, which is reflected in the change in weight. At the beginning of the paper, the theory and experimental bases of vibration testing and analysis are introduced to understand the principles of modal parameter specification. Verification of the boundary conditions used in the simulation was performed using the experimental method and it is described in the next part of the article. Tests confirmed the consistency of the values achieved by both approaches. Thus, the same boundary conditions could be used to specify the dependence of natural frequencies on the change in the geometry ofthe gear (which is associated with weight reduction). Numerical analysis was performed by FEM analysisusing PTC Creo software. Experimental modal analysis was performed using a PULSE measurement system.
Katarina Monkova; Peter Monka; Jozef Tkac; Romana Hricova; Dusan Mandulak. Effect of the Weight reduction of a Gear Wheel on Modal Characteristics. MATEC Web of Conferences 2019, 299, 03002 .
AMA StyleKatarina Monkova, Peter Monka, Jozef Tkac, Romana Hricova, Dusan Mandulak. Effect of the Weight reduction of a Gear Wheel on Modal Characteristics. MATEC Web of Conferences. 2019; 299 ():03002.
Chicago/Turabian StyleKatarina Monkova; Peter Monka; Jozef Tkac; Romana Hricova; Dusan Mandulak. 2019. "Effect of the Weight reduction of a Gear Wheel on Modal Characteristics." MATEC Web of Conferences 299, no. : 03002.