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Computational simulation of cross-roll leveling of rods
Benešovský, Marek ; Vrbka, Jan (referee) ; Petruška, Jindřich (advisor)
Final thesis describes two variants of computational models to simulate cross-roll leveling of rods, which are based on the Lagrangian approach to describe the continuum. Implementation of both variants was performed in ANSYS software, and their main difference lies in the choice of the type of elements for the discretization. An integral part of this thesis is the description of the principle, which is an evaluation of the curvature of the rod after completion of the simulation leveling. In the other part of the work are presented the results, which are then compared with realized experiment and simulation algorithm for cross-roll leveling based on the Euler approach. The final part is dedicated to the optimal settings of the leveller.
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Computational analysis of residual stresses in autofrettaged high pressure rails
Blaha, Jakub ; Petruška, Jindřich (referee) ; Vrbka, Jan (advisor)
The master‘s thesis is aimed on numerical simulation of autofrettage of high pressure fuel vessel – rail in Common Rail system. First there is described Chaboche model, which is later used for simulation of autofrettage. There are described different approaches which can be used to obtain sufficient material model. Then there is observed influence of these different approaches on stress state of rail within the process of autofrettage. Suitability of Chaboche model for autofrettage and re-autofrettage simulations is assessed by comparing with more complex Jiang model. In the end there is a study of influence of autofrettage pressure on different properties, especially on residual stresses.
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Stress, deformation and safety analysis of the recumbent bicycle frontal composite axle
Ondrejka, Jan ; Majer, Zdeněk (referee) ; Vrbka, Jan (advisor)
This diploma thesis deals with creation of computational model of AZUB recumbent tricycle composite axle for stress strain analysis. The thesis consists of four main parts. The first part contains introduction to the offer of full suspended tricycles from the most known manufacturers. Furthermore it contains introduction to composite materials that makes the main element of AZUB´´s suspension, and the description of the AZUB´´s front axle. In the second part there is detailed compilation of computational model for purpose of stress strain analysis of three load states. The effect of specific material and geometry parameters on axle behavior is discussed with the aim of choosing the most appropriate variant. Third part deals with the manufacturing of the front axle prototype and with tests leading to input data for numerical model and verification of computational model. Modifications and changes that lead to manufacturing of the second prototype are content of the last part. Based on this experience some recommendations for future development of the numerical axle model and the front axle suspension itself are formulated.
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Study of the Chaboche´s plasticity model complexity influence on the stress and deformation at the high pressure vessel
Paraska, Boris ; Obdržálek, Vít (referee) ; Vrbka, Jan (advisor)
The main aim of this thesis is to define material parameters of Chaboche model of plasticity. Adjustment of the parameters has to correspond to the experimental datas. These datas are represented by an uniaxial strain controlled test curve for fewer than two cycles and also by cyclic stress-strain curve. After that, an cyclic tension-compresion test for various parameters of Chaboche´s model of plasticity is simulated in an ANSYS software. Finally, the most suitable configuration of Chaboche´s model of plasticity is used for cylindrical thick-walled body. Cylindrical body represents a simplified model of high-pressure tank of fuel (diesel) – rail in Common Rail system.
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Influence of essential parameters on the radial clearance and stress-strain states in ball bearings
Šperka, Václav ; Vrbka, Jan (referee) ; Fuis, Vladimír (advisor)
Master thesis is focused on the research of influence of selected substantial parameters on stress – strain states in the deep groove radial ball bearing. The influence of radial load is analyzed, such as the influence of size of the bearing and row of the bearing, also influence of radial clearance is quantified. Next, the influence of thermal distribution in the bearing is analyzed for different combinations of thermal distributions and radial clearances. Conclusions from analyses are then used in the last task – suggestion of radial clearance for customer – specified assembly. Problem is solved using the finite element method (FEM) in pre/post processor MSC.Patran and solver MSC.Marc. To make analyses faster the substantial parameters are implemented in the algorithm for automatic generation of the bearing calculation (batch file).The theme of this thesis was commissioned by ZKL - Research and development, a. s.
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Strength and lifetime analysis of the hydraulic key lock
Klíč, Jan ; Majer, Zdeněk (referee) ; Vrbka, Jan (advisor)
Theoretical part of this master thesis is focused on the theory of fatigue life. The second part deals with the assesment of static strength the closing flap in front of water turbine. Futher fatigue analysis of the closing flap is performed considering corrosive environment. The aim is to verify the required service lifetime of 50 years.
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Stress, deformation and reliability analysis of heated compound pipeline
Hladký, Maroš ; Vosynek, Petr (referee) ; Vrbka, Jan (advisor)
Diplomová práca je zameraná na napäťovú a deformačnú analýzu elektricky vyhrievaného potrubia a príslušných častí. Cieľ práce je analýza častí potrubia samostatne a vo vzájomnom pôsobení voči medzným stavom, a zistenie maximálneho dovoleného zaťaženia. Potrubie je analyzované voči medznému stavu pružnosti a maximálnej dovolenej deformácií. Podpora je analyzovaná s cieľom nájsť adekvátne zaťaženia a silové reakcie počas inštalačnej fázy. Nakoniec je vyšetrované vzájomné pôsobenie. Potenciálne prekročenie daného medzného stavu je diskutované v adekvátnej kapitole.
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The assembly gap influence on the stress and strain at the radial ball bearing
Rašovská, Hana ; Prášil, Jiří (referee) ; Vrbka, Jan (advisor)
This master thesis deals with the influence of assembly clearance on strain and stress in the radial ball bearing. The theme of this thesis was commissioned by ZKL - Research and development, a. s. For six different assembly clearances and selected ball bearing was made force-loaded static analysis of global computational models. Subsequently was made a static analysis of local computational models loaded by strain according to the results of global models. The output of analysis of local models was sizes of stress, which led to the analysis of bearing with two other models of material. For the solution of the problem was used pre/post processor Patran and solver MSC.Marc.
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