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Numerical analysis of visco-elastic material models
Michálková, Veronika ; Lang, Rostislav (referee) ; Trcala, Miroslav (advisor)
The serviceability of concrete structures is a multiphysical problem where viscoelasticity is interrelated with plasticity or damage, among other things. This work focuses on the analysis and testing of an isotropic viscoelastic material model based on a generalized Kelvin chain. The Kelvin chain is described in detail for 1D strain and then its application to multi-axial 2D plane strain is shown. In this paper, a total of 3 studies are carried out using the Kelvin chain. The first study concerns the analysis of the Kelvin chain with damage on several benchmark refinement problems. The second study compares the results of the Kelvin chain including damage with an experiment on a three-point beam bending problem. The third study concerns the analysis of the Kelvin chain with damage on a stress relaxation problem in a loaded concrete beam and compares the results with the ANSYS calculation and experimental measurements. The aim is to analyze the effect of the parameter on the time-dependent behavior of the concrete and also the effect of the number of time increments N on the result.
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Design of test rig for long-term testing of couplings intended for railroad applications
Machálek, Ondřej ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
The master thesis deals with design of test rig for long-term testing of coupling appointed to railway vehicles. At first, there is made a brief research which is related to railway coupling used for transmitting a torque. This is followed by an analysis of the most used power devices to derive real loads conditions of tested couplings. There is chosen the most appropriate conception based on made analysis and it is followed by the description of designed components. There is made a verification of modal properties non-purchased components which is necessary part of the thesis. Numerical modal analysis was performed in ANSYS Workbench software. In the end of the thesis there are included stress-strain analysis of the chosen designed components.
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Stress and strain analysis of different total knee endoprostheses on tibia bone tissue performance
Boháč, Petr ; Borák, Libor (referee) ; Marcián, Petr (advisor)
This diploma thesis deals with the stress-strain analysis of the influence of various total knee endoprosthesis on the periprosthetic bone tissue of the tibia. The first part of the thesis describes the problem situation and the research study related to the issue. The second part of the thesis describes the basic knowledge suitable for understanding the issues addressed. The third part of the thesis describes in detail the process of creating computational models, which should make the used methodology reproducible for possible further studies. The next part of the work analyses and presents the results of computational modelling using the finite element method. Based on the Frost hypothesis, the effects of various total knee endoprosthesis on the periprosthetic tibial bone tissue at a specified maximum load appearing in the walking cycle are evaluated and compared. At the end of the thesis, the possible consequences of this analysis are mentioned.
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Study of the influence of magnetic fields on biological tissue
Vlachová Hutová, Eliška ; Fiala, Pavel (referee) ; Bartušek, Karel (advisor)
The aim of this research is to explore the influence of magnetic field on early somatic embryos (ESEs) of spruce and pine. The magnetic field is gradual. This is important for the experiment, each cluster of ESE was exposed to magnetic field of different intensity. The resulting report of this experiment consists of the comparison between various methods of image analysis and the difference in growth of ESEs due to different exposure to magnetic field and surrounding temperature. Enclosed is a proposal of ESE size computing algorithm from a given image.
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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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Braking of an induction machine
Mareček, Šimon ; Janda, Marcel (referee) ; Mach, Martin (advisor)
The work is focused on the braking of an induction engine and the risks associated with it. In the first part, there are readers acquainted with the technical parameters of the induction engine, which is used for simulations. The second part focuses on the simulation program Ansys Maxwell and the finite element method. In the third part, there are readers introduced to a general description of the induction machine. The fourth part consists of countercurrent braking. The penultimate part is devoted to dynamic braking. The last part contains a brief introduction to generator braking. The chapters focused on braking are supplemented by simulated waveforms.
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Analysis of mechanical loads of selected structural parts of the excavator during operation
Busta, Michal ; Maňas, Pavel (referee) ; Vosynek, Petr (advisor)
This thesis is focused on the issue of computational modeling of soil harvesting while using the compact excavator from the company DOOSAN BOBCAT EMEA s.r.o.. The solution consists in creating two computational models in Rocky DEM and Ansys Mechanical. Rocky DEM software is used to solve the disconnection of soil by excavator components using the discrete element method. The outcome includes courses of forces and moments during the particular time of the individual joints of the model that was used. The obtained courses are then applied as an external load to the joint of a selected structural part of the analyzed model using a kinematic model in ANSYS Mechanical. The kinematic model consists of simplified geometry models of individual parts of the excavator arm, and a more detailed geometry model of the analyzed part of the arm. All the parts are connected to each other by rotational bonds representing joints. A static structural analysis of the mechanical stress is performed in ANSYS Mechanical for the prepared model during the simulated process. Finally, the selected structural part is assessed with respect to the elastic limit and fatigue strength.
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Application of finite element method to solve plane problems
Langer, David ; Vosynek, Petr (referee) ; Návrat, Tomáš (advisor)
The subject of this thesis is application of finite element method to solve planar problems of mechanical stress of machine components. The goal of the first part of the thesis is to provide the reader with an overview of commonly used FEM software and it's capabilities, both freeware and commercial solutions. Second part of the thesis deals with the usage of freeware for FEM calculations. The last part of the thesis consists of documentation to the FEM software created as a subject of this thesis. The documentation provides a detailed view of the selected type of calculation.
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FEMM program - preparation of education materials
Pešek, Michal ; Huzlík, Rostislav (referee) ; Vítek, Ondřej (advisor)
The manual is supposed to introduce to users the program FEMM. It is designed for solving low freqency electromagnetics problems. It shoul allow students, who are not experienced with work in english interface programs, make a model and set parametres needed for successful solution of required problem. There is description of setting and location of important program elements. Users have to quickly understand, how to work in program. FEMM work indeed in two dimensional mode and it is simplier, than expensive 3D programs, on the other hand, he is free for commercial and noncommercial use. It makes this program very interesting for home using by students. Licence restricton is related with program code itself and selling only.
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Role of Plasticity in Nitinol Fatigue
Shayanfard, Pejman ; Seiner,, Hanuš (referee) ; Dlouhý, Antonín (referee) ; Šandera, Pavel (advisor)
Disertace analyzuje vliv koncentrátorů napětí na průběh martensitické transformace, vznik plastické deformace a její vliv na přerozdělení napětí a vznik zbytkového pnutí a reziduálního martenzitu v okolí koncentrátorů v prvcích ze slitin s tvarovou pamětí NiTi. Vliv je analyzován v režimech superelastického isotermálního cyklování a aktuačního cyklování, t.j. teplotního cyklování pod vnějším napětím. Disertace využívá pro vyhodnocení vlivu experimentální přístup spolu s numerickými simulacemi metodou konečných prvků na modelových případech tenkých pásků ze slitin NiTi opatřených půlkruhovými vruby. V experimentální části je vyhodnocován vliv koncentrátorů pomocí termomechanických experimentů s využitím metod obrazové korelace a rentgenové mikrodifrakce pro lokální analýzu deformací a fázových objemových podílů v průběhu cyklování v okolí vrubů. Simulace metodou konečných prvků poskytují komplementární informace o průběhu napětí, deformací a martensitické transformaci, zejména o vývoji jednotlivých složek celkové deformace, tj. elastické a plastické, a vývoji zbytkového pnutí a s ním souvisejícím zbytkovým martensitem.Disertace je dále doplněna o numerickou analýzu vlivu konstrukce stentů na lokální cyklický průběh martensitické transformace a jeho vliv na únavové vlastnosti.
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