|
|
Design and realization of experimental equipment for determination of residual stress of bent samples
Novotný, Lukáš ; Návrat, Tomáš (referee) ; Krejčí, Petr (advisor)
The master thesis is focused to design and realization of experimental equipment for researching of residual stress determination for specimen with non-uniform distribution stress along the depth. Literature search study of problematic was performed and it was used for elaboration of chapters about origin of residual stress, their classification and chapters about methods, which are used for measuring of residual stress and their determination. The following part explains the design of experimental equipment and stress-strain analysis of selected parts of this equipment. Then the final design of equipment is presented, including complete production drawings, and it’s explained final assembling of experimental equipment. Final chapter is devoted to examinable loading of specimen.
|
|
|
Influence of residual stress on pressure vessel part fatigue life
Boleloucký, Václav ; Vincour, Dušan (referee) ; Létal, Tomáš (advisor)
This bachelor’s thesis deals with the impact of a residual stress, caused by an applied cyclic pressure, on fatigue life of a pressure vessel part (flat end–cylinder connection). Bachelor’s thesis includes the design of the pressure vessel according to CSN EN 13 445 regulations, analytical solution in Maple software, from which stresses and deformations are determined. Then the results of the analytical approach are firstly verified by a FEM modelling in ANSYS Workbench software and secondly compared to each other in graphs and discussed. From the values of stresses in FEM, analysis fatigue life expectations are calculated with the respect to CSN EN 13 445 regulations, for two cases. First one, where a pressure test is applied and second one, where the pressure test is not applied before the pressure vessel is put into service. In the conlusion the obtained results are discussed.
|
|
| |
|
|
Design of optimal parameters of multilayer ceramic protective coating for high temperature applications
Dohnalík, Petr ; Hrstka, Miroslav (referee) ; Ševeček, Oldřich (advisor)
The main objective of this work was to design a suitable composition of a protective coatings, made of several different layers of specific materials - with respect to residual stress, induced due to a mismatch in thermal expansion coefficients of each layer. Protective coating in this work means both the thermal and the environmental barrier. These coatings protect components against high temperatures and harsh environment. In this work, necessary theoretical background in the field of the thermal and environmental barrier coatings is introduced. There are mentioned some basic design approaches, commonly used materials and processing methods for the coating structure. The literature review gives an overview of modeling of such coated structures, in particular it is devoted to the thermal barrier coatings deposited by air plasma spray process. The next chapter closely describes classical laminate theory used for calculation of residual stresses in the coating. One of the assumptions of this theory is homogenous temperature field through the coating’s thickness. However, in this work was revealed a way to extend the classical lamination theory of such cases, in which the temperatures vary along the thickness of the coating. In the practical part, the analytical model was used for designing suitable properties of some coatings, which were consists of two, three and four layers. The calculations were performed both for constant temperature and for the temperature gradient. All results obtained from analytical approach were verified by numerical calculations.
|
|
|
The influence of geometry and cutting tool parameters on residual stress during machining of the pressure containers
Berka, Martin ; Kouřil, Karel (referee) ; Strejček, Jan (advisor)
This thesis deals with the influence of changes in cutting parameters and tool geometry on residual stress inside the material. I examine the influence by deep drilling. Changing the cutting parameters concerns the alteration of the tool feed and the pressure of the coolant during the process. The influence of tool geometry is studied by using two different single edge cannon drills. The research was realized in cooperation with Bosch Diesel Ltd. The theoretical part includes a description of the injection system, in which a high-pressure container is contained. The high-pressure container was used to evaluate the influence of the cutting parameters and tool geometry on residual stress. Furthermore, the theoretical part deals with the deep drilling technology used and the theory of residual stresses. The practical part shows the measurement parameters and the corresponding results. In the conclusion of this thesis, a technical-economic evaluation of the measurement is conducted.
|
|
|
Comprehesive Theoeretical Analysis of Ring-Core Method for Residual Stress Determination
Civín, Adam ; Vlk, Miloš (advisor)
Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.
|
|
|
Comprehesive Theoeretical Analysis of Ring-Core Method for Residual Stress Determination
Civín, Adam ; Holý, Stanislav (referee) ; Plánička, František (referee) ; Frydrýšek,, Karel (referee) ; Vlk, Miloš (advisor)
Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.
|
|
|
Manufacture of optical mirrors for high-frequency antenna
Muzikant, Dušan ; Bumbálek, Bohumil (referee) ; Sedlák, Josef (advisor)
This thesis deals with problems with manufacturing of high frequency elliptic and hyperbolic optic mirrors, which makes one of the most important functional parts of parabolic satellites made for biggest and highest placed international astronomical radio-telescope in the world - ALMA, which is built on Chajnantor plateau in Chille in South America. Individual chapters are designed in the flow of technological process of manufacturing, containing theoretical and practical analysis of the problems. Content of the thesis leads especially to description and clarification of individual causes of problems during manufacturing.
|
|
| |
|
| |
guest ::
