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Stress-strain analysis of a crane arm
Mora, Lukáš ; Halabuk, Dávid (referee) ; Fuis, Vladimír (advisor)
The content of this bachelor’s work is a summarization of types of tower cranes and subsequent stress-strain analysis of the crane arm of the crane type 150EC-B8 Litronic located on the Šumavská street in Brno. Analytical stress-strain analysis is calculated with equations of equilibrium using joint method in various types of loading of the construction with MAPLE software. Numerical calculation is executed on 3D model of the construction in software ANSYS. The aim of this bachelor work is the verification of the correctness and comparison results of analytic calculation with numeric calculation and evaluation of the results from a limit states and deformation standpoint.
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Assessment of the thermomechanical behaviour of perspective nuclear fuel for reactivity insertion accidents
Halabuk, Dávid ; Suk, Ladislav (referee) ; Martinec, Jiří (advisor)
The objective of this master’s thesis is to simulate thermo-mechanical behaviour of nuclear fuel in a pressurized water reactor during a reactivity initiated accident. An important part of this work is focused on examination of processes which occur during such accident and on creation of a detailed overview of material properties of nuclear fuel and fuel cladding which are necessary for simulations that closely reflect reality. Simulations in this thesis examine cases of fresh or irradiated nuclear fuel for two types of fuel cladding, Zircaloy-4, a material that is currently used in nuclear reactors, and ceramic matrix composite material made of SiC. The thesis also presents comparison of results with a corresponding international benchmark and an assessment of the influence of selected input parameters on obtained results.
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Using free programs for topology optimization on selected problems in solid mechanics
Flídr, Ondřej ; Halabuk, Dávid (referee) ; Vosynek, Petr (advisor)
This bachelor thesis examines open-source software for topology optimization, analyzes their possibilities on selected problems of solid mechanics and verifies the results by the finite element method. The theoretical part describes the principles and methods by which the tasks of topology optimization can be solved. This is followed by search for open-source software using these methods. The calculation process in selected software is described in detail in solving sample tasks in the penultimate part. In the last chapter, the best open-source software are compared with each other and also with commercially distributed Ansys Workbench 19.2. The output is an evaluation of the usability of individual open-source software in industry. This thesis can also serve as a manual for using selected programs for inexperienced users.
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Topology optimization of movable, fixed and based plate of electromechanical injection-moulding machine
Kecík, Samuel ; Halabuk, Dávid (referee) ; Návrat, Tomáš (advisor)
The master thesis deals with the design of geometry of plates of the injection molding unit using the FEM tool Topological Optimization. The reason for this is to reduce the weight of these components, which is beneficial in the transport and assembly of the injection molding machine. However, the final models of geometry of plates must meet certain requirements in terms of the limit state of deformation, the limit state to the critical value of the equivalent stress. This condition involves both limit state of elasticity and limit state of fatigue. Computational modeling and also Topological Optimization are performed in ANSYS Workbench.
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Fuel element characterization
Halabuk, Dávid ; Suk, Ladislav (referee) ; Martinec, Jiří (advisor)
This bachelor thesis describes the fuel rods of VVER reactors. In addition to general description of fuel rod, there is also overview of the nuclear fuel used in the past and at present in Czech and Slovak nuclear power plants, as well as overview of the new trends in development of nuclear fuel. Big part of the thesis is focused on description of nuclear fuel and fuel cladding properties and the individual processes affecting fuel rod during fuel burnup. Next part describes in detail the causes of fuel failures occurring in VVER reactors. The last part of the thesis includes calculation of changes of deformations and stresses occurred in fuel cladding during pellet-cladding interaction. Calculation is done for four different shapes of fuel pellets and in addition to deformation and stress analysis, there are also calculated axial dilatations of fuel column and radial temperature distributions in fuel rod.
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Possibilities of the description of stress-strain curves for computational simulations
Košťál, Josef ; Halabuk, Dávid (referee) ; Šebek, František (advisor)
Tato bakalářská práce se zabývala problematikou určování křivky zpevnění (taktéž „flow curve“) z experimentálně změřených výstupů tahové zkoušky a regresí této zjištěné křivky nelineárními vztahy. Byl prezentován teoretický základ zkoušky tahem a jejího výstupu a také byly popsány rozdíly mezi smluvním a skutečným napětím a přetvořením. Dále byla zmíněna analytická korekční metoda (Mirone-La Rosa) pro odhadnutí trendu křivky zpevnění. Tato metoda využívá standardních výstupů tahové zkoušky. Dále byly vypsány elasto-plastické po částech spojité materiálové modely, a navíc byly vybrány a detailněji rozebrány 4 nelineární vztahy pro popis křivky – Hollomon, Ludwik, Swift a Voce. Následně byla použita metoda konečných prvků pro určení a zkalibrování křivky zpevnění oceli 18CrNiMo7-6, změřené tahovou zkouškou. Pouze standardní výstup tahové zkoušky byl potřeba pro kalibraci. Křivka zpevnění byla zkalibrována iterační výpočtovou metodou na základě srovnání reakční síly ze simulace se silou z experimentu. Nakonec bylo vytvořeno uživatelské prostředí pro nalezení nejlepší regrese ze čtyř vybraných nelineárních vztahů.
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Optical measurement of crack length utilizing the DIC method
Dziubek, Jan ; Halabuk, Dávid (referee) ; Ščerba, Bořek (advisor)
The thesis deals with the measurement of crack length using digital image correlation. The theoretical part of the thesis presents the method of digital image correlation, crack problems, and also introduces conventional methods for measuring crack length. There are currently no universal procedures in the field of crack length measurement using DIC. Different authors have only proposed different procedures to find the crack tip. Three different methods are used to determine the crack length using digital image correlation. Use of the edge detection method in the displacement field, the inflection point search method and the deformation threshold method. The aim of this work is to describe and compare these approaches.
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Finite element solution of axially loaded bars using quadratic element
Janáčik, Lukáš ; Halabuk, Dávid (referee) ; Vaverka, Jiří (advisor)
This bachelor thesis describes an algorithm for programming finite-element model with quadratic elements for axial loaded bar. In the introduction, we define the basic concepts of mechanics of materials, which are used in this thesis and are necessary to understand problems, for which finite element method was formulated. The thesis clarifies a transition from basic differential equation to weak formulation, which is the base of finite element method. We define element matrices and describe transition to global matrices, relating to the whole body. Then describe implementation of boundary conditions and postprocessing of the results, necessary for calculation and displaying of other unknowns. In the practical part, 3 illustrative problems are presented and calculated numerically in FEM solver using Matlab, analytically and in software ANSYS Workbench. Results are then compared and evaluated. Problems have different boundary conditions (linear axial load, tempered cross section, statically indeterminate fixation). Results of displacement and normal stress for programmed solver are identical to those from Ansys (using the same settings) and analytical solution (after more elements are added, if necessary). Problem with tempered cross section was simulated in Ansys using plain stress, because the program can’t define bar with tempered cross section. This revealed sheer stress contained in parts of cross section further from centreline, which are not calculated in our FEM solver and in some cases might be significant.
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The use of superelements in solving large systems of MKP
Hluška, Milan ; Halabuk, Dávid (referee) ; Návrat, Tomáš (advisor)
This bachelor thesis deals with the utilization of superelements in finite element method simulations. First, the basic theory of FEM and superelements is explained. The principles and procedures of using superelements in ANSYS and its scripting language APDL is described next. Third part focuses on custom-made program that illustrates the appication of superelements, and its results of an exemplary calculation are compared with the results from ANSYS APDL in the last part.
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