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Stress-strain analysis of the Gbely drilling tower
Vizváry, Peter ; Kovář, Jaroslav (referee) ; Fuis, Vladimír (advisor)
The content of the bachelor's thesis is focused on the stress-strain analysis of a drilling tower located in Gbely. Its main goal is to compile equations of static equilibrium for the analytical solution of the structure and its subsequent numerical verification using the created 3D computational model based on various static loads or changes in the degree of static determinacy. The first part of this work summarizes the theory of the bar and of bar systems, the basic limit states and the finite element method (FEM). The second part contains a search on the history of oil production in Slovakia, its discoverer and the development of deep drilling and production technologies. The third part describes the drilling tower in Gbely. The content of the fourth part is the creation of a 3D computational model of a real structure, which should represent the drilling tower as accurately as possible. The most comprehensive is the fifth part, which consists of the design of a simplified structure, writing the equations of static equilibrium for the analytical solution, creating a 3D computational model for numerical verification of the analytical solution and evaluating the conclusions to which the individual variants of the solution led.
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Analysis of performance of embankment constructed on subsoil improved by vertical drains
Kováč, Vladimír ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
The thesis deals with the back analysis of the instrumentated embankment on the subsoil, improved by prefabricated vertical drains. The first part is devoted to the theory of consolidation calculation. Furthermore, the author deals with a parametric study of the analytical calculation of prefabricated drains and the comparsion of the analytical and numerical solution. The last and the largest part of the work is a back analysis of the embankment which was built as a part of the subsoil improvement near the Suez Canal in Egypt by Keller GmbH.
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A Stefan problem of heat conduction with phase change and its exact solution
Kesler, René ; Mauder, Tomáš (referee) ; Klimeš, Lubomír (advisor)
This bachelor's thesis deals with analytical solutions of heat conduction problems with phase change which are known as classical Stefan problems. At the beginning a differential equation of heat conduction is derived and a mathematical model of Stefan problem is formed. The greatest attention is paid to the derivation of analytical solutions for cases in which these solutions are obtainable. The MATLAB environment was chosen for implementation of the obtained solutions. The thesis also includes a description of the program and its graphical interface in MATLAB. The applicability of the program is demonstrated in several phase change problems.
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The usage of Salome Meca workbench for task solution in the field of solid mechanics
Nytra, Michal ; Návrat, Tomáš (referee) ; Vosynek, Petr (advisor)
Submitted bachelors thesis deals with solution of tasks of body mechanics in open-source workbench Salome Meca and FEM solver Code_Aster. In the beginning is short theoretical introduction to finite element method a basic theory to strength of materials. Then follows series of tasks, which will test solver and workbench. We will compare results with analytical solution (if exists), eventually with available commerical software Ansys. There are 3 static structural tasks (beams, axisymetric bodies). Next task is from dynamics, searching of natural frequencies and vibration of plate during harmonic excitation. The last one is steady-state-thermal combined with static structural. In the conclusion are summarized advantages and disadvantages of open-source softwares. Results of workbench Salome Meca vary from analytical solution maximal to 10 %, what is in engineering praxis suffcient accuracy.
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Transient response of layered orthotropic strip to transverse load
Adámek, V. ; Valeš, František ; Červ, Jan
This work concerns the transient response of an infinite two-layered strip subjected to a transverse load of impact character. The material of each layer is assumed to be specially orthotropic, i.e. the material and geometric axes coincide. Moreover, the material is modelled as linear viscoelastic using the model of standard linear viscoelastic solid such that the damping behaviour of the strip for long wavelengths and long times can be addressed. The non-stationary wave phenomena in the strip are studied using analytical approach. The system of equations of motion for the case of 2D plane-stress problem is solved using the classical method of integral transform. Once the formulas for the Laplace transforms of fundamental mechanical quantities are derived, the numerical inverse Laplace transform is used to obtain the response in time domain for a strip with free-fixed boundaries. The results for a strip composed of two orthotropic layers of specific material properties are presented in this work. Finally, this solution is confronted with the results of numerical simulations reached by a professional FE code.
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FLow in cracs
Ocásek, Adam ; Veselý, Jindřich (referee) ; Haluza, Miloslav (advisor)
This Master’s thesis investigates the flow in sealing gaps of impeller within pumps and turbines. Sealing gaps are installed to improve the volumetric efficiency in this type of fluid machinery. Despite present extensive research this subject has not been entirely documented and the thesis’ aim is to improve our knowledge in this matter. At the beginning, the practical experiment is used in order to establish appropriate numerical description of flow in seals and to calibrate software FLUENT. In chapter five, the thesis analyses the influence of seal design on volumetric efficiency of pumps and turbines and defines its optimal construction to improve the efficiency. The thesis then examines the effect of rotor eccentricity on flow properties, flow rate and pressure distribution within the sealing gap. In the last section, through chapters six to eight, the flow results provided by numerical solution in FLUENT and selected analytical equations, or their modified forms, are being discussed. The degree of correspondence between the results is also studied.
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Comparision of methods for nonlinear dynamic sytems solution
Krejčí, Jaroslav ; Lošák, Petr (referee) ; Dušek, Daniel (advisor)
The aim of this work is to make a solution of nonlinear dynamic system with one degree of freedom using various approximate analytical methods and perform their comparison. The beginning of the work describes the basic characteristics of nonlinear dynamic systems, methods of modelling and a description of the basic analytical methods of solution. In the following part is the solution of the system using described methods and comparing of results. In conclusion the methods are compared with final element method by program ANSYS.
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Analytical approaches of local stability investigation applied to piecewise linear vibrating system - Kelvin-Voigt impact oscillator
Kocanda, Lubomír
Dynamical behaviour of soft impact oscillator is multifarious with plenty of manifold behaviour kinds commensurated with system parameters. The stability analysis of soft impact oscillator is very important for dynamic investigation. Floquet theory or Ljapunov exponent approach can be applied in numerical integration. However, contrary to numerical integration results processing, the analytic-numerical approaches give better view of the dynamical nub despite its' facing mutual very diverse terms. Approaches based on eigenvalue problem and small difference method presented in authors past papers are eked out with this contribution. This paper aim is to obtain the result of the local stability investigation approaches in analytical form.
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