Publikační činnost Katedry částí a mechanismů strojů / Publications of Department of Machine Parts and Mechanisms (347)

Permanent URI for this collectionhttp://hdl.handle.net/10084/131950

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků částí a mechanismů strojů (347) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 17 out of 17 results

Modern design of carrier for overhead conveyor
(MDPI, 2024) Hruzík, Lukáš; Struž, Jiří; Trochta, Miroslav; Klapetek, Lukáš; Pišťáček, Daniel
Modern industry should apply modern design in the construction of production facilities. This is typically the case with belt production, where parts are moved towards the worker, or when moving parts from the factory to the warehouse and shipping area. There is a relatively high energy consumption associated with moving these parts. The size of the consumption is mainly determined not only by the size of the transported components and the transport technology, but also by the design of the hoppers used for transport. One way to reduce material handling costs is to make the equipment used for moving parts more efficient. A more efficient carrier should, above all, be lighter. Topological optimization can serve very well for this weight reduction. Of course, the reduction in weight not only has an effect on lower power consumption, but also on the wear of other components. Hence, later in this article, we try to quantify these impacts and assess how much benefit the use of a modern designed carrier can bring. It is also important to consider the cost of producing new carriers versus modifying existing ones. The paper describes the application of the modern designed carrier and compares it with the existing carriers as well as modified existing carriers.
Static transmission error measurement of various gear-shaft systems by finite element analysis
(JVE International Ltd., 2024) Czakó, Alexander; Řehák, Kamil; Prokop, Aleš; Rekem, Jakub; Láštic, Daniel; Trochta, Miroslav
Transmission error (TE) is a significant parameter related to gears vibration widely investigated by many authors using different approaches. However, in previous studies, spur and helical gears were mainly examined. There is a lack of studies addressed to double helical and herringbone gears and a comparison among several types of gearing with parallel axes. In this paper, spur, helical, double helical, and herringbone gears are analyzed in terms of static transmission error (STE), contact pressure and tooth root stress. Static contact analyses were conducted using the finite element method (FEM) which is often considered a tool for validating other methods and approaches. Moreover, three variants of boundary conditions of each gear type are introduced, including flexible shafts and the effect of a tip relief modification at sole gears, without shafts, was analyzed. In addition, a concept of a compact test rig intended for STE measurements at low loads was presented. The results have shown, among other things, significant influence of the shaft stiffness and boundary conditions on meshing characteristics.
Unsymmetrically distributed bolt axial forces between symmetrically spaced bolts of clamping sleeve
(MDPI, 2023) Hruzík, Lukáš; Struž, Jiří; Trochta, Miroslav; Začal, Jiří
This article deals with the uniformity of the distribution of axial forces between the individual bolts of the clamping sleeve. Clamping sleeves are machine components connecting the shaft to the hub using contact force. For sleeve pretension, bolts are used and positioned symmetrically with respect to the axis of the clamping sleeve. Though the bolts are placed symmetrically around the axis, the bolt axial forces are not uniformly distributed when the bolts are tightened according to the manufacturer’s catalog. First, this article describes the procedure for tightening the sleeve bolts according to the manufacturer’s catalog. In the next part of the article, an FEA simulation of sleeve tightening is performed. The FEM simulation is then compared with the values found by measurement.
A study of independency on fuzzy resolving sets of labelling graphs
(MDPI, 2023) Shanmugapriya, Ramachandramoorthi; Hemalatha, Perichetla Kandaswamy; Čepová, Lenka; Struž, Jiří
Considering a fuzzy graph G is simple and can be connected and considered as a subset H = { (u(1), s(u(1))), (u(2), s(u(2))), ...(u(k), s(u(k)))}, |H|= 2; then, every two pairs of elements of s - H have a unique depiction with the relation of H, and H can be termed as a fuzzy resolving set (FRS). The minimal H cardinality is regarded as the fuzzy resolving number (FRN), and it is signified by Fr(G). An independence set is discussed on the FRS, fuzzy resolving domination set (FRDS), and Fuzzy modified antimagic resolving set (FMARS). In this paper, we discuss the independency of FRS and FMARS in which an application has also been developed.
The effect of cutting tool geometry on surface integrity: A case study of CBN tools and the inner surface of bearing rings
(MDPI, 2023) Čepová, Lenka; Čep, Robert; Chałko, Leszek; Dvořáčková, Štěpánka; Trochta, Miroslav; Rucki, Miroslaw; Beránek, Libor; Mizera, Ondřej; Chyshkala, Volodymyr
In this paper, a practical issue of the application of cubic boron nitride (CBN) cutting tools for the machining of steel 100Cr6 thin-walled bearing rings is addressed. Three geometries of the commercially available CBN cutting inserts were tested at different machining parameters. The effect of geometry was assessed in terms of surface integrity, considering 2D profile parameters, 3D topography of the surface, and residual stresses in the surface layer. The results were sometimes contradictory, since the same cutting inserts provided the largest and the lowest values of the topography parameters, dependent on different cutting conditions. In general, CBN cutting inserts with XCEL geometry ensured the smallest profile parameters Ra and Rz, and the spatial parameters of Smr1 exhibited the largest values among all tested tools, suggesting reduced wear resistance. Residual stresses analysis did not reveal any inacceptable or potentially dangerous surface layer state after machining.
Influence of symmetry of tightened parts on the force in a bolted joint
(MDPI, 2023) Začal, Jiří; Folta, Zdeněk; Struž, Jiří; Trochta, Miroslav
This article discusses the issue of force behavior in a pre-tensioned bolt that is part of a symmetrical flange connection, loaded with an operating load parallel to the bolt axis. The first part describes the issue being dealt with in detail. The next part offers a brief description of the generally known theoretical approach to the solution, and also outlines the limitations of this approach. This part is followed by a theoretical analysis of working load behavior in the bolt of the analyzed device, using Finite Element Method (FEM). In this article, a comparison of several different approaches to the solution can be also found, followed by a description of the experiment preparation and its results. The obtained values also serve as a subject for reverse iterative analysis carried out using ANSYS software. The aim is to find a proper modification to the symmetric calculation model that would be consistent with the results of measurements from technical practice. All results achieved are described in the final part of the article.
Comparison of standard and nonstandard gear root fillet considering root stress and manufacturing possibilities
(MM Science, 2023) Klapetek, Lukáš; Dobiáš, Jiří; Struž, Jiří; Folta, Zdeněk
In this paper, root stress, manufacturing possibilities and limitations of standard and nonstandard tooth root fillet of spur gears are examined. Nowadays, standard trochoidal root fillet is used the most as an economical trade-off between tooth strength and manufacturing complexity. A disadvantage of the trochoidal root fillet, especially in spur gears with less than 17 teeth, is undercutting which minimises strength of tooth root, introduces stress concentration, and deteriorates meshing conditions. This study focuses on different root designs, namely elliptical and novel cycloidal root fillets. Root stress in gears with different root designs is analysed by FEM and compared with analytical equations according to ISO. The possibility of producing nonstandard root fillet gears by hobbing and limitations of surface finishing are considered as well. Analysis reveals stress differences between each of the root fillet shapes and their relative advantages and disadvantages.
Comparative analysis of different softwares in terms of parameters optimized by topological optimization
(MM Science, 2023) Struž, Jiří; Hruzík, Lukáš; Klapetek, Lukáš; Trochta, Miroslav
In recent years, topological optimization has become a powerful tool for designers and engineers in the technical world. The principle of this method is based on optimizing a given optimization region by minimizing or maximizing one or more objective functions, e.g. stiffness, mass, or natural frequency of the structure. For this reason, software companies developing CAD or FEM software have included topological optimization in their portfolio, either as a modular part of the software or as a dedicated program. In general, users of these programs do not have a mathematical definition of the software background, and it is not clear what variations in calculations may occur when using different software. For this reason, a comparative analysis of the selected software was performed to determine the differences between the results assuming the same boundary conditions and machine parts such as computing time, weight and volume.
Thermal behavior modeling based on BP neural network in Keras framework for motorized machine tool spindles
(MDPI, 2022) Košarac, Aleksandar; Čep, Robert; Trochta, Miroslav; Knežev, Miloš; Živković, Aleksandar; Mlađenović, Cvijetin; Antić, Aco
This paper presents the development and evaluation of neural network models using a small input-output dataset to predict the thermal behavior of a high-speed motorized spindles. Different neural multi-output regression models were developed and evaluated using Keras, one of the most popular deep learning frameworks at the moment. ANN was developed and evaluated considering the following: the influence of the topology (number of hidden layers and neurons within), the learning parameter, and validation techniques. The neural network was simulated using a dataset that was completely unknown to the network. The ANN model was used for analyzing the effect of working conditions on the thermal behavior of the motorized grinder spindle. The prediction accuracy of the ANN model for the spindle thermal behavior ranged from 95% to 98%. The results show that the ANN model with small datasets can accurately predict the temperature of the spindle under different working conditions. In addition, the analysis showed a very strong effect of type coolant on spindle unit temperature, particularly for intensive cooling with water.
Detection of mechanical stress limiting effects of crane structure deformation
(MM Science, 2021) Hrabovský, Leopold; Folta, Zdeněk
The paper presents a construction design and results of laboratory tests of so-called mechanical stress detectors, which can be used to detect the deformation of the steel structure of a crane and to amplify the mechanical signal from the effect of the so-called crane skewing, which is included among occasional loads acting on the crane. The values of the relative elongation of the detectors corresponding to the magnitude of the instantaneous tensile force were obtained by conducting experimental mechanical tests. Detectors of a known extent of deformation were installed on a two-girder overhead crane bridge, where they measured axial forces generated during the controlled deformation of the crane bridge. In practice, the instantaneous values of the axial forces recorded by the individual detectors make it possible to regulate the speed of the crane drive wheels and thus eliminate, in a relatively short time, the undesirable effects of deforming the crane bridge and friction of the crane wheels on the sides of the rail heads.
Probabilistic analysis of the maximal load of industrial machines
(MM Science, 2021) Folta, Zdeněk; Skalný, Pavel; Matějka, Petr; Trochta, Miroslav; Pišťáček, Daniel
This study describes the statistical analysis of peak forces of industrial washing machines. The data source comes from twelve different machines. The measurements are done using a force gauge installed in places for fastening screws. A new software based on LabView has been developed to gauge the acting forces. To determine extreme force values, various probability distributions are applied. Furthermore, a convex combination of lognormal distribution is used in more complicated cases. The parameters of the lognormal mixtures are determined using modified an Expectation-maximization algorithm. Finally, the achieved results are interpreted with regard to the engineering design and to the operating reliability.
Influence of shape of pressure vessel shell on bolt working load and tightness
(MM Science, 2021) Začal, Jiří; Pavlík, Jan; Kunzová, Ivana
The area of flange joints with gasket includes many types of pressure vessels, which are mainly defined by the purpose of use and specific load conditions. These differences in definitions caused the existence of many types of pressure vessels with different shell shapes. Calculations of basic shapes are defined by standards. However, in some fields of engineering practice, these shapes are atypical. The article discusses the issue of circular sealed flange joints with a nonstandard shape of the pressure chamber shells. The aim of this article is to describe influence of shape of pressure vessel shell on bolt working load and the final tightness of the sealed joint using FEM.
Prediction of buckling force in hourglass-shaped specimens
(Springer Nature, 2021) Gjengedal, Ragnar; Fyllingen, Ørjan; Heiník, Vojtěch
It is important to avoid buckling during low-cycle fatigue testing. The buckling load is dependent on the specimen shape, material properties, and the testing machine. In the present investigation of hourglass-shaped specimens the importance of the diameter to radius of curvature is examined. Diameters of 5 and 7 mm are examined with a ratio of radius of curvature to diameter of 4, 6, and 8. The machine used is an Instron 8800 with elongated rods for a climate chamber. This leads to a reduced stiffness of the machine during compression testing. A finite element model (in Abaqus) is developed to identify the critical buckling force. For hourglass-shaped specimens, buckling means onset of sideways movement, without a drop in the applied load which is typical for conventional Euler buckling. The onset of sideways movement is identified experimentally by analysis of the data from extensometer and the load cell. This model is verified by experiments and fits within 0.6 to - 11% depending on the specimen diameter and diameter to radius of curvature ratio. The smallest deviations are obtained for the 7-mm-diameter specimen with deviation varying from 0.6 to - 3.3% between the model and the experiments. The current investigation is done with a commercially available hot rolled structural steel bar of o16 mm.
Design procedure of a topologically optimized scooter frame part
(MDPI, 2020) Jančar, Lukáš; Pagáč, Marek; Měsíček, Jakub; Štefek, Petr
This article describes the design procedure of a topologically optimized scooter frame part. It is the rear heel of the frame, one of the four main parts of a scooter made with stainless steel 3D printing. The first part of the article deals with the design area definition and the determination of load cases for topology calculation. The second part describes the process of the topology optimization itself and the creation of the volume body based on the calculation results. Finally, the final control using an FEM (Finite Element Method) analysis and optimization of created Computer-Aided Design (CAD) data is shown. Part of the article is also a review of partial iterations and resulting versions of the designed part. Symmetry was used to define boundary conditions, which led to computing time savings, as well as during the CAD model creation, where non-parametric surfaces were mirrored to shorten the design time.
Comprehensive view on racing car upright design and manufacturing
(MDPI, 2020) Huňař, Marek; Jančar, Lukáš; Krzikalla, David; Kaprinay, David; Srníček, Dávid
This paper deals with the design of an upright using a topological optimization. This type of optimization is a relatively young and rapidly evolving area of computational mechanics that seeks to make multiple material savings that cannot be achieved by conventional methods. The optimized upright was utilized in a fully functional prototype of the student formula within the Formula Student competition. The main objective of the optimization was to meet the requirements of the physical properties, weight, stiffness, and strength of the upright. The initial model of the upright was iteratively optimized using topological optimization and a finite element static analysis to obtain the final model. Using the finite element analysis, its behavior in operation within individual load cases was predicted. Symmetry was used to mirror the finished model to obtain the opposite upright of the other side of the car. Finally, the topologically optimized upright was compared with an upright made by conventional methods.
3D printed belt wheels for use in design of bicycles
(MM Science, 2020) Sniehotta, Patrik
The article describes how it is possible to use 3D printing for printing belt wheels for bicycles. New categories of bikes keep appearing in the market. For the use, specially cities that are bikes, that use belt instead of a traditional chain. With new generations of belts, this power transmission can be used on mountain bikes. But a belt-driven bike must have a special frame, because the belt cannot be disconnected like a classic chain. Even with modern 3D CAD applications a company needs to make a prototype and check their design. That is not only important for the function of the bicycle, but also to prove the assembly or maintenance processes. In comparison with a chain, the belt-driven system is more expensive. For small companies, it is then difficult to buy different gearing combinations, just for checking the design. In this case, the 3D printing comes in handy, because it can produce very quickly cheap belt wheels with different tooth combinations or design of the belt wheel. With more advanced methods (like the selective laser sintering) of 3D printing, it is possible to produce even functional belt wheels that have the same ore even better properties compared to traditional injection molding. This article shows the possibilities in the prototyping of belt wheels with different 3D printing methods.
Remarks and corrections to the standard ISO 6336
(Politechnika Śląska. Wydział Transportu, 2018) Němček, Miloš
The standard ISO 6336 for the calculation of load capacity of spur and helical gears was introduced in 2006. There were some later amendments, but several typographical and other errors. These can cause some misunderstandings during applications of the standard and are irritating for its users. This contribution seeks to highlight some aspects of the use of this standard, as well as drawing users' attention to the errors it contains and, at the same time, properly worded content. To fully appreciate this article, the reader is advised to have a copy of the standard itself. Parts 3 and 6 of the standard are covered in the contribution.

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