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Dynamic Model of Harmonic Gearbox
Garami, Boris ; Lošák, Petr (referee) ; Hadaš, Zdeněk (advisor)
This thesis deals with the design of a dynamic model of a harmonic drive. It includes a theoretical study aimed at the analysis of the harmonic drive gearing principle and its nonlinear properties. The first part of the practical section deals with the analytical calculation of the nondeformed geometry of the Flexspline. Based on these results, several simulations in ANSYS are created to identify torsional characteristics of a harmonic drive. These simulation models are further enhanced by the analysis of clearance, backlash and inaccuracies and their impact on torsional properties. By using MATLAB /Simulink, several dynamic submodels are created representing the individual characteristics of nonlinearities in harmonic drives. Furthermore, a comprehensive dynamic model is created of the mechatronic system which is describing all nonlinearities and kinematic error of the transmission. The dynamic model is also experimentally verified based on its damping properties.
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Modal Analysis of the Blades Row Tied with Z-tie
Valoušek, Tomáš ; Chromek, Lukáš (referee) ; Lošák, Petr (advisor)
This thesis is about modal analysis of the rotor blades row tied with Z-tie. Thesis was solved by finite element system ANSYS. Cyclic symmetry was used in this thesis with the aim of obtain eigen frequency of bladed disc. The next aim of this thesis was to find eigen frequency of the free rotor blades and to compare it with frequency obtained from experiment. 3D model was created by 3D scanner and CAD system CATIA.
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Influence of the surrounding tissue on the stresses in brain arterial aneurysms
Lipenský, Zdeněk ; Burša, Jiří (referee) ; Polzer, Stanislav (advisor)
This thesis is focused on stress in brain aneurysms. It consists of three parts. First part is aimed for gaining information about the topic from scientific resources. Next part consists of analyses of geometry of cerebral aneurysms on the computed wall stress. Analyses are performed on four basic geometrical models and results are being discussed. The risky areas in each investigated shape have been identified as well as the comparisons of stress between those shapes have been performed and the most dangerous shape among investigated shapes has been determined. Third part investigates the influence of surrounding tissue on the brain aneurysm. Conclusion of this thesis is that brain gray tissue has positive yet negligible effect on the computed wall stress.
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Dynamical Simulation of a System with Contact Problem
Raisinger, Jan ; Keršner, Zbyněk (referee) ; Frantík, Petr (advisor)
This work deals with the simulation of a dynamical system with a contact problem represented by the contact of a bicycle tube with a tire during inflation and loading of a bicycle wheel. In the first part the work defines the basics of dynamical systems a contact problems and introduces the methods used for following simulations. The practical part of the work desribes the process of converting a real system of rim-tube-tire objects to a computional model by determining its geometry and material characteristics as a continuous object and its subsequent discretization, introduces the program used for the subsequent simulations (FyDiK 2D) and shows the results of said simulations.
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Dynamical Simulation of a System with Contact Problem
Raisinger, Jan ; Keršner, Zbyněk (referee) ; Frantík, Petr (advisor)
This work deals with the simulation of a dynamical system with a contact problem represented by the contact of a bicycle tube with a tire during inflation and loading of a bicycle wheel. In the first part the work defines the basics of dynamical systems a contact problems and introduces the methods used for following simulations. The practical part of the work desribes the process of converting a real system of rim-tube-tire objects to a computional model by determining its geometry and material characteristics as a continuous object and its subsequent discretization, introduces the program used for the subsequent simulations (FyDiK 2D) and shows the results of said simulations.
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Approximation, numerical realization and qualitative analysis of contact problems with friction
Ligurský, Tomáš ; Haslinger, Jaroslav (advisor) ; Segeth, Karel (referee) ; Rohan, Eduard (referee)
Title: Approximation, numerical realization and qualitative analysis of contact problems with friction Author: Tomáš Ligurský Department: Department of Numerical Mathematics Supervisor: prof. RNDr. Jaroslav Haslinger, DrSc., Department of Numerical Mathe- matics Abstract: This thesis deals with theoretical analysis and numerical realization of dis- cretized contact problems with Coulomb friction. First, discretized 3D static contact prob- lems with isotropic and orthotropic Coulomb friction and solution-dependent coefficients of friction are analyzed by means of the fixed-point approach. Existence of at least one solution is established for coefficients of friction represented by positive, bounded and con- tinuous functions. If these functions are in addition Lipschitz continuous and upper bounds of their values together with their Lipschitz moduli are sufficiently small, uniqueness of the solution is guaranteed. Second, properties of solutions parametrized by the coefficient of friction or the load vector are studied in the case of discrete 2D static contact problems with isotropic Coulomb friction and coefficient independent of the solution. Conditions under which there exists a local Lipschitz continuous branch of solutions around a given reference point are established due to two variants of the...
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Bifurcations in contact problems with Coulomb friction
Ligurský, Tomáš ; Renard, Y.
To explore the bifurcation in this contact problem, we have taken uniform meshes with 4096, 16384, 65536 and 262144 triangles. We shall show that the bifurcation behaviour is more complex here. Branches 1 and 4 approach one another for finer meshes, and they disappear both for the finest mesh. Nevertheless, regarding the branching of the corresponding contact problem with forces h = (h1,h2) over the plane h1-h2, one can find it stable and convergent, again. \n
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