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Homogenization of closed foam structures using Kelvin cell
Škoviera, Jozef ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor‘s thesis deals with creating calculation model of the foam structure based on Kelvin cell with closed porosity. First aim of this work is homogenization of the foam structure by identical deformation response in foam structure and continuum. Second aim is follow-up parametrical study of influence of characteristic measures of Kelvin cell on material characteristics. Task was solved in ANSYS software by method of final elements. Resultant dependences rendering was done in MATLAB software.
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Micro-cellular impact absorbers
Rakušan, Jakub ; Ševeček, Oldřich (referee) ; Skalka, Petr (advisor)
This bachelor thesis focuses on micro-cellular impact absorbers. The micro-cellular absorber converts the kinetic energy of the impacting object into the strain energy of the internal structure of the absorber. The thesis focuses on two types of absorbers, namely the absorber with internal auxetic structure and the absorber with internal non-auxetic structure. The same porosity has been kept for both internal structures for further comparison of the characteristics of both the absorbers. As part of this thesis, an impact test was simulated. In this test, objects (cylinders) of different diameters, the same length (identical to the absorber thickness), and different kinetic energy were impacted into the absorber. The finite element method (explicit solution) was used to solve this problem. The output of the study was a comparison of simulations of the impact test into auxetic and non-auxetic structures.
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Stress-strain analysis of front seat folding mechanism
Gergeľ, Erik ; Gašparec, Andrej (referee) ; Skalka, Petr (advisor)
This master thesis deals with creation of computational model for stress - strain analysis of front car seat folding mechanism. The calculation has been done using FEM for static and dynamic load case. The results displayed the critical area of mechanism and determined the value of force when the safety of mechanism is not guaranteed and the force when the mechanism failure occurs. According to results from both load cases was made a statement that is necessary to model the dynamic load cases respecting the load time course.
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Radial turbine runner design with reduced moment of inertia
Votava, Ondřej ; Skalka, Petr (referee) ; Fuis, Vladimír (advisor)
This master’s thesis deals with topological optimization of the impeller of a radial turbocharger turbine. It focuses on reducing the moment of inertia with unchanged aerodynamic properties. The optimization was carried out using CFD, thermal and structural analysis. The computational modeling was performed using the finite element analysis in ANSYS. The work proposes models of the impeller with the topological modification of the internal structure. Based on the values of moment of inertia, the stress and the strain the most suitable model was selected.
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Frequency modal analysis of blade package of steam turbine
Přikryl, František ; Skalka, Petr (referee) ; Malenovský, Eduard (advisor)
This thesis deals with comparison the results of the frequency modal analysis of blade package of steam turbine with stiffening or damping bounding elements. Computational model was created through the finite element method, using cyclical symmetry. The results were compared with experimental analysis and analysis in VIPACK programme. Thesis also contains creating the solid blade model, using the reverse engineering.
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Finite element simulation of stresses in plasma-sprayed thermal barrier coating
Lacina, Zdeněk ; Slámečka, Karel (referee) ; Skalka, Petr (advisor)
Bachelor‘s thesis focuses on the study of stress states in thermal barrier coatings. A two-dimensional computational model of thermal barrier coating was created using ANSYS software, on which the process of cooling of thermal barrier from working temperature to room temperature was simulated .The stress distribution in ceramic layer was studied then. The output of this thesis is a description of the influence of roughness, amplitude and TGO layer on the stresses in a ceramic layer of thermal barrier. Matlab software was used to process the results.
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Computational analysis of auxetic structures application potential in impact absorbers
Dohnal, Jakub ; Skalka, Petr (referee) ; Ševeček, Oldřich (advisor)
Master thesis deals with the analysis of the application potential of auxetic materials in the field of shock absorption (absorption of impact energy). Due to their cellular structure and specific geometry, these materials are characterized by a negative Poisson’s ratio, which means that they are able to reduce their transverse dimension under compressive stress in the longitudinal direction. The aim of this work is to use this interesting property for the absorption of kinetic energy. After the introduction, devoted to the theoretical basis and research in the field of auxetic structures, a numerical FEM model is described in detail. The task of the model is to study the mechanical response of auxetic and conventional cellular structure to an impact loading. An explicit solver in the commercial software LS-DYNA is used to numerically simulate fast processes. The results of the analyses are used to compare auxetic and conventional structures and quantify the differences in their ability to dampen the kinetic energy of the impact effectively and gently. It also serves to demonstrate the influence of individual geometric or material parameters on impact attenuation. At the end of the work, numerical simulations are confronted with available experiments in order to verify the informative value of computational models and to point out the application potential of auxetic structures in the discussion. There are also partial recommendations for their design so that they best serve the intended purpose.
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Stress - strain analysis of bridge structure during the train passage
Kolárik, Matej ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor’s thesis concerns the stress-strain determination of the rail bridge in Komárov during the train crossing. The task was solved in the program ANSYS which uses the finite element analysis. The following factors were taken into consideration: a non-loaded state, the state of a train assembly load, and detailed observation of a continual crossing of diesel train. Following the series of results the most dangerous state was defined and the safety calculated.
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Three-point bending test of foam laminates
Kelecsényi, Matej ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor thesis deals with the formation and the spread of disorder of crossbeams in core of composite, in ceramic foam with homogeneous structure formed by Kelvin cells with open porosity loaded by three-point bending test. The method of finite element in software ANSYS was used for the creation of composite sample calculation model as well as in calculation of sample loads. The results of the thesis are the values of the sample reaction force and of the first main tension on crossbeams of foam core sample obtained by loading of the foam composite sample. The area of breaches crossbeams was inferred from the analysis of composite core structure breach. In conclusion were evaluated the results obtained in this thesis.
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Napjatostně deformační analýza mostu v Třineckých železárnách
Ščerba, Bořek ; Skalka, Petr (referee) ; Fuis, Vladimír (advisor)
The bachelor thesis analyses stress and deformation of the truss construction. The first point of the thesis is a research, which includes obtaining information about the construction, for exemple dimensions, loads, purpose, history etc. Then, calculation models are created considering a different level of simplification. Two analytical models are crutial for the thesis – one statically determinate and the other statically indeterminate. They are used for analysing two different loads applied to the construction using methods of solid mechanics – it’s own weight and its own weight in combination with a weight of a vehicle that is driving through. Afterwards, the statically inderteminate model is verified using finite element method (FEM).
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