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Timig relay for Y/D automatical start
Kovář, Jaroslav ; Vondruš, Jiří (referee) ; Hejkrlík, Jan (advisor)
This project is concerned with a concept of timing circuit used for an automatic start of the asynchronous engine Y/D. By pressing the button START, is the concactor ( the relay ) activated. After injury timing delay the concactor Y drops out and simultaneously the concactor D pulls in. By pressing the button STOP, the concactor drops out. The concept of this electric circuit is quite simple, even if good hand-mindedness of a solver is required substantially. Especially in a soldering process and in scheming PCB in the computer program EAGLE.
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Stress and deformation analysis of railway bridge over the Svratka River
Kovář, Jaroslav ; Žák, Stanislav (referee) ; Fuis, Vladimír (advisor)
This thesis deals with stress and strain analysis of real truss bridge structure. This structure is modelled as plane bar system. The opening part dedicates to theory, which is further used for calculations. The calculation part dedicates to compare statically determinate and indeterminate variation of structure for load by own weight and passage of the train. Analytic calculations are numerically verified with program ANSYS. In thesis is assessed concentration of stress, when the rivet drops out of the structure. The next part of thesis dedicates the spatial model of bridge, which is compared witch plane model.
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Failure probability of the ceramics part using Weibull weakest link theory
Kovář, Jaroslav ; Návrat, Tomáš (referee) ; Fuis, Vladimír (advisor)
This thesis compares Weibull weakest link theory with inclusion of one and all three principal stresses. Principal stresses needed for this theory were calculated with finite element method. The informational research is in the introduction of this thesis. It includes ceramic materials, Weibull weakest link theory, Gaussian quadrature over spherical surface and ceramic head of hip joint endoprothesis. Theoretical part is used for next calculations of probability of failure. The probability of failure of ceramic rod loaded by four-point bending is calculated in first calculations. This task is solved as contact in the next step. Next part of this thesis is about selection of suitable method of numerical integration. This method will be used in the calculation with all three principal stresses. The results of calculation with all three principal stresses are compared with the results of the calculation which includes only first principal stress. Firstly, this is done for cylindrical body and then used on head of hip joint endoprothesis. In the last part of this thesis, probability of fracture of head hip joint endoprothesis with shape deviation of nominal conicity is calculated.
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Stress-strain analysis of stadium lighting mast
Tokoš, Richard ; Kovář, Jaroslav (referee) ; Fuis, Vladimír (advisor)
The bachelor thesis contains an analysis of a steel structure that serves as lighting in a football stadium. The main goal is to create a bar system, the equation of static equilibrium and the deformation condition and I will analytically solve the stress and strain. Then I will create a model in ANSYS and calculate the stress and strain numerically. The bachelor thesis contains a comparison of the results of these methods.
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Analysis of the use of Code_Aster in solving the limit state of fatigue strength
Busta, Michal ; Kovář, Jaroslav (referee) ; Vosynek, Petr (advisor)
This bachelor’s thesis deals with the analysis of the use of Code_Aster in the calculations of the limit state of fatigue strength. The first part is the research in fatigue analysis using the solver Code_Aster and in the second part the know-how of Code_Aster usage is used to solve three tasks of the limit state of fatigue strength. Acquired results are compared with analytical solutions and with the student licence of the numerical software Ansys Workbench 19.2. In conclusion, all the results are analysed.
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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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Calculation of the probability of the endoprosthesis ceramic head with shape deviation
Kučerková, Miroslava ; Fuis, Vladimír (referee) ; Kovář, Jaroslav (advisor)
The main content of the diploma thesis is to determine the probability of failure of the hip joint endoprosthesis ceramic head. The assumption is the three-axis state of stress. To calculate the probability of failure three principal stresses, which are determined numerically using finite element method, are needed. Ceramic materials, hip joint endoprosthesis and Weibull weakest link theory, which describes the calculation of the probability of failure of ceramic components, are described in the first part of the thesis, after that, the second part with calculations follows. The first model, for which the stress and probability of failure were calculated, is a cylindrical body. The stress distribution in it was determined numerically as well as analytically. Its primary goal is to verify the developed algorithm of calculating the probability of failure. This algorithm is also used in calculations of probability of failure of ceramic femoral head. The suitability of using averaged principal stress values was also verified here. In the next part of the thesis, a model of an ideal ceramic head was created and its probability of failure was calculated. The impact of friction, penetration and the size of elements used for discretization of the model on the value of probability of failure were all analysed. The evaluated findings were subsequently used in the calculations of the model of ceramic head with an deviation from the ideal ovality. The impact of this change on the resulting probability of failure in comparison with the ideal state was evaluated in the conclusion.
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Calculation of the probability of the ceramic component failure according to the Weibull’s weakest link theory
Kučerková, Miroslava ; Fuis, Vladimír (referee) ; Kovář, Jaroslav (advisor)
Weibull weakest link theory is used to determine the probability of failure of ceramic components. This bachelor thesis examines the cylindrical body, beams and rotating circular and intercircular disc. In these bodies it is possible to identify course of the stress in an analytical way. The research part of the work approaches ceramic materials in terms of their structure, composition, method of production or mechanical properties. From a theoretical point of view, Weibull weakest link theory for uniaxial and triaxial stress in the body is described and required relations for further calculations are given here. In the second part, the probability of failure of previously mentioned models is calculated. Beams are stressed by a simple and four - point bending. The impact of the body size on the probability of failure is also analyzed. The cylindrical body is solved for different variants, which are compared afterwards. At last, the effect of operating speed on the probability of failure of the rotating circular and intercircular disc is investigated.
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Mechanical analysis of lift
Tesař, Jakub ; Kovář, Jaroslav (referee) ; Fuis, Vladimír (advisor)
The bachelor thesis deals with analysis of the system with seven solids with consideration of passive effect. In the first part of thesis describes the basics of statics and dynamics. Description of neutral and passive links, release method and reduction method. In the second part of the work are describing effects of passive effects on the movement state of the elevator. The individual bodies were released in the GeoGebra program. The aim of the example is to determine the contract forces in the links, check functionality of the links and state of motion. The solution took place in the computer program Matlab
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