Publikační činnost Fakulty strojní / Publications of Faculty of Mechanical Engineering (FS)

Permanent URI for this collectionhttp://hdl.handle.net/10084/106752

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Now showing 1 - 11 out of 11 results

Influence of temperature and number of passes during twist channel angular pressing (TCAP) on the microstructural, mechanical, and corrosion properties of Mg-4Li-Ca
(Springer Nature, 2024) Bednarczyk, Iwona; Dobkowska, Anna; Hilšer, Ondřej; Rusz, Stanislav; Pastrňák, Martin; Čada, Radek; Jabłońska, Magdalena; Tkocz, Marek; Kowalczyk, Karolina; Palgan, Daria; Nečas, David; Mizera, Jarosław
In this study, the possibilities of improving the mechanical and corrosion properties of Mg-4Li-1Ca processed using twist channel angular pressing (TCAP) were investigated. There was a special focus on the optimization of the TCAP parameters through analyzing how the temperature of TCAP influences the microstructural, mechanical, and corrosion properties of the alloy, and how an increasing number of TCAP passes affects these properties. It was shown that among specimens extruded with one pass, the highest mechanical properties were achieved at 180 degrees C. Microstructural changes were noted at higher temperatures and caused a decline in the mechanical properties. The influence of an increasing number of passes through the TCAP channel was rather minor and did not lead to significant microstructural strengthening. In contrast, the best corrosion performance was observed after four passes at 180 degrees C and after a single pass at 300 degrees C. The results of this study show that TCAP is an efficient method for the grain refinement of hcp-structured metals, lowering the costs of the plastic deformation of Mg-based alloys.
Provozování letišť
(Vysoká škola báňská – Technická univerzita Ostrava, 2017) Červinka, Michal; Němec, Vladimír; Soušek, Radovan
Létání a letecká doprava patří k zajímavým a mnohdy prospěšným1 činnostem člověka. I když se letectví potýká v současnosti i po celou dobu své existence s mnohými těžkostmi a problémy, vždy se v oboru pohybovali schopní a vzdělaní lidé, kteří byli schopni najít řešení a letectví posunout na vyšší úroveň. Problematika letišť není výjimkou. Letadla i jiné létající aparáty potřebují ke svému vzletu a přistání letiště, ať už se jedná o lety největších dopravních letadel Airbus A-380 nebo lety větroňů, případně padákové kluzáky (paragliding). Ve všech případech je potřeba, aby byly zajištěny technické podmínky pro vzlet i přistání, od požadavků na prostor bez překážek a orientace ve směru proti větru u sportovců, až po rozměry letiště, jeho světelné, radionavigační vybavení, letištní terminál a další infrastrukturu potřebnou pro bezpečný provoz. Důležité je i odbavení letadel, cestujících a nákladu, s ohledem na místní podmínky a požadavky zákazníků například leteckých společností, leteckých cestujících, společností přepravujících náklady, atd.
SCFF23 : From Smart City to Smart Factory for Sustainable Future : conceptual framework, scenarios and multidiscipline perspectives : International Conference
(VSB - Technical University of Ostrava Faculty of Mechanical Engineering Department of Machining, 2023) Slaninková, Aneta; Quoc, Phu Ma
The international conference SCFF23 is organized for researchers, experts, and students to share their vision about the future under the concept of “From Smart City to Smart Factory for Sustainable Future” from multidiscipline perspectives. The aim of the conference is to provide an opportunity for participants with different expertise to meet up and share their knowledge, disruptive ideas, solutions to existing problems that hinder us from moving forward to more modern and sustainable life using technologies. The conference facilitates mutual exchanges of experiences and establishment of long-lasting international cooperations. The scope of the conference includes discussions about Innovative and Sustainable technologies, solutions, and frameworks for applications of state-of-the-art technologies to Smart City and Smart Factory.
Overcoming the strength-ductility trade-off in additively manufactured AlSi10Mg alloy by ECAP processing
(Elsevier, 2022) Snopiński, Przemysław; Matus, Krzysztof; Tatíček, František; Rusz, Stanislav
To overcome the trade-off between strength and ductility of the additively manufactured AlSi10Mg alloy used in the automotive and aerospace industries, samples with multilevel structural heterogeneities were produced using single-pass ECAP at 150 degrees C and 200 degrees C. The microstructures of these samples were composed of partially ruptured Al/Si cellular networks and alternatively arranged zones of elongated (pancaked) grains separated by wide zones composed of ultrafine grains. Experimental results demonstrated that AlSi10Mg deformed at 150 degrees C, exhibited a superior ultimate tensile strength (UTS) of ~541 MPa, but limited ductility. The sample deformed at 200 degrees C exhibited both high ultimate tensile strength (UTS ~463 MPa) and excellent elongation at break of ~16.3%. Those results revealed a superior combination of strength and ductility that originated from bimodal grain size distribution, Orowan bowing, mechanical twinning of the hard Si phase, and back-stress hardening. Our results shed new light on the unexploited potential in improving the mechanical properties of additively manufactured alloys.
Čerpací technika a potrubí: návody do cvičení
(Vysoká škola báňská - Technická univerzita Ostrava, 2022) Blejchař, Tomáš; Drábková, Sylva
Tato skripta jsou určena jako podpora výuky ve cvičeních z předmětů Čerpací technika, Čerpací technika a potrubí a Doprava kapalin. Ve skriptech je v silně zjednodušené formě probrána základní teorie, týkající se problematiky čerpacích systémů. Závěr každé kapitoly sestává z řešených příkladů, ve kterých je aplikována předchozí teorie. Ve výkladu se předpokládá znalost mechaniky tekutin, jejíž studium by mělo předcházet studiu výše zmiňovaných předmětu, které na mechaniku tekutin obsahově navazují. Při řešení příkladů bylo nutné některé hodnoty zaokrouhlovat, ale výpočty byly provedeny v plném rozsahu desetinných míst, proto může v některých příkladech vzniknout při samostatném řešení číselná odchylka. Autor děkuje doc. Ing. Sylvě Drábkové, Ph.D. za připomínky a cenné rady při tvorbě tohoto učebního textu.
Proceedings of the 25th International Conference on Hydraulics and Pneumatics
(Vysoká škola báňská - Technická univerzita Ostrava, 2022) Noskievič, Petr
The International Conference on Hydraulics and Pneumatics organised by the Czech Association for Hydraulics and Pneumatics (CAHP), which is a part of the Czech Mechanical Engineering Society, and by the Department of Control Systems and Instrumentation of the Faculty of Mechanical Engineering at the VŠB-Technical University of Ostrava is a traditional meeting point of the specialists both from the industry and the universities with more than fifty years long tradition. The 25th conference is the first event organized in the present form after the COVID-19 period, during which all activities of the CAHP were done on line. The return to the normal situation opened the possibilities to organize again workshops and conferences as the meetings of the professional community with live discussion between researchers and academic staff.
Dual rolls equal channel extrusion as unconventional SPD process of the ultralow-carbon steel: finite element simulation, experimental investigations and microstructural analysis
(Springer Nature, 2021) Jabłońska, M. B.; Kowalczyk, K.; Tkocz, M.; Bulzak, T.; Bednarczyk, Iwona; Rusz, Stanislav
The paper presents results of FEM modelling as well as properties and microstructure of the ultralow-carbon ferritic steel after the unconventional SPD process-DRECE (dual rolls equal channel extrusion). Based on the conducted numerical simulation information about the deformation behaviour of a steel strip during the DRECE process was obtained. The simulation results were experimentally verified. The influence of DRECE process on hardness distribution, fracture behaviour and microstructure evolution of the investigated steel was analysed. The increase of steel strength properties after subsequent deformation passes was confirmed. The microstructural investigations revealed that the processed strips exhibit the dislocation cell microstructure and subgrains with mostly low-angle grain boundaries. The grains after processing had relatively high dislocation density and intense microband formation was observed. It was also proved that this unconventional SPD method fosters high grain refinement.
Identification of pollution sources in the urban atmosphere
(Polskie Towarzystwo Przeróbki Kopalin, 2017) Sýkorová, Barbora; Raclavská, Helena; Matýsek, Dalibor; Kucbel, Marek; Raclavský, Konstantin; Růžičková, Jana
Identification of PM10 particles in the city of Olomouc (the Czech Republic) was aimed at determining the proportion of inorganic and organic compounds. Organic compounds in PM 10 represent 30-36% of PM10, of which 21-25% is biogenic material (spores were identified). The rest of 10 to 15% of organic matter is represented by anthropogenic processes. Combustion processes (35.1 to 40.9% of PM10) and emissions from transport (20.0 to 22.9% of PM10) have the main share in the PM particles, minerals from resuspension - weathering processes and mechanical processes of construction activity account for around 9% of the particles and Fe - particles also constitute about 9%. The iron concentration in the aerosol is in accordance with the values measured in other European cities. Mineral phases in the inorganic aerosol were determined by X-ray diffraction. Both natural and anthropogenic crystalline phases were identified - quartz, clay minerals (kaolinite), feldspar, calcite, dolomite, iron oxides (magnetite), gypsum, boussingaultite, mascagnite and koktaite.
Comparison of different FETI preconditioners for elastoplasticity
(Elsevier, 2017) Čermák, Martin; Hapla, Václav; Kružík, Jakub; Markopoulos, Alexandros; Vašatová, Alena
This paper illustrates parallel solution of elastoplastic problems with hardening based on the TFETI domain decomposition method with several preconditioning strategies. We consider von Mises plasticity with isotropic hardening using the return mapping concept for one time step. To treat nonlinearity and nonsmoothness, we use the semismooth Newton method. In each Newton iteration, we solve a linear system of equations using the TFETI domain decomposition method with lumped, Dirichlet, or no preconditioner. Our PERMON software is used for the numerical experiments. The observed times and numbers of iterations are backed up by the regular condition number estimates. Both preconditioners accelerate the solution process in terms of the convergence rate. For the worst conditioned benchmark, the most expensive Dirichlet preconditioner gives the lowest computational times. This lets us suggest the Dirichlet preconditioner as the default choice for engineering problems.
Total-FETI domain decomposition method for solution of elasto-plastic problems
(Elsevier, 2015) Čermák, Martin; Hapla, Václav; Horák, David; Merta, Michal; Markopoulos, Alexandros
In this paper we present an algorithm for the parallel solution of the rate-independent elasto-plastic problems with kinematic hardening. We assume the von Mises plastic criterion and the associated plastic flow rule. The time discretization is based on the implicit Euler method. The corresponding one-time-step problem is formulated in the incremental form with respect to the unknown displacement and discretized spatially by the finite element method. We use an ‘external’ algorithm based on a linearization of the elasto-plastic stress–strain relation by the corresponding tangential operator and we parallelize the arising linearized problem by the Total-FETI method. The numerical experiments were carried out using our novel C/C++ library FLLOP (FETI Light Layer On top of PETSc) at HECToR supercomputer located at EPCC, UK.
Modelling of outbursts and ejections occurrences during steel production
(Hrvatsko Metalurško Društvo, 2015) Malindžáková, Marcela; Rosová, Andrea; Baranová, Vladena; Futó, Jozef
The application of small industrial cameras linked to a computer to create models for monitoring of adverse events in the steel making process is referenced. Presented models were created by analyzing video recordings that were captured in areas that could directly threaten human life. In laboratory conditions it is possible to analyze the recorded data and then already known mathematical methods are used to evaluate phenomena that are characterized in operating conditions by rapid pace and their monitoring on site is difficult and dangerous.

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