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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Zpětná analýza sypané přehradní hráze a predikce jejího chování při mimořádných zatěžovacích stavech / Back analysis of embankment dam and prediction of its behaviour during accidental design situations

Krajčovič, Ján January 2019 (has links)
Diplomová práce představuje vytvoření softwarového 2D MKP modelu přehrady Slezská Harta v České Republice za pomoci softwaru PLAXIS 2D. V úvodu práce je analýza vodní nádrže, vytvořené jako zásobárna vody a protipovodňové dílo. Analýza sleduje geomorfologii, geologii, konstrukci tělesa hráze, použité materiály a metody, a stávající monitorovací zařízení. Pro pochopení tvorby 2D MKP modelu jsou předloženy a definované metody použitých analýz - metoda konečných prvků, analýza prosakování, materiálové modely, citlivostná analýza. Následně byla definována tvorba struktury modelu - určení posloupnosti použitých analýz, definování vstupních dat a mezních podmínek a tvorba kalibračního segmentu. V závěrečné části práce je analýza dosažených výstupů rozsáhlého testování modelu, jejich korelace s reálnými naměřenými hodnotami a celkové shrnutí přínosu vytvořeného modelu pro jeho využití při předpovídání chování přehrady v extrémních případech.
342

Vliv reziduálních napětí na odhad životnosti polymerních trubek / Influence of Residual Stress on Lifetime Prediction of Polymer Pipelines

Poduška, Jan January 2019 (has links)
The lifetime of plastic pipes for water supply and other applications is demanded to exceed at least 50 years. Such a long lifetime is difficult to prove by standard testing methods like the hydrostatic pres-sure test. However, it is possible to calculate an estimation of the lifetime, as the most frequently oc-curring mechanism of failure of plastic pipes is the creep crack propagation and subsequent failure. The method is based on describing the crack propagation by parameters of the linear-elastic fracture mechanics. An important part of this method is a finite element simulation of crack propagation in a pipe loaded by various types of loads. Residual stress, a side product of solidification after extrusion, is one of these loads. This thesis begins with an introductory part and literature review of the relevant topics – most of all the typical material properties of the pipe materials, mechanisms of failure, methods of residual stress determination suitable for plastic pipes and their results, methods of testing the materials and calculating lifetime. After the introduction, the problems to be solved are defined. The description of the residual stress state in the wall of various plastic pipes is the main topic. Both tangential (hoop) and axial residual stress in pipes of different dimensions and materials are determined using a combination of experiments and numerical simulations. Also, a simplified method of tangential residual stress is designed that can provide a sufficiently precise description of the tangential resid-ual stress state and is not difficult to carry out. A method to include the residual stress in the lifetime calculations and its influence on the lifetime is also dealt with. Apart from residual stress, the influence of soil loads in case of a buried pipe is studied. The residual stress can also influence the experimental determination of crack growth rate. If the CRB (cracked round bar) test is used to measure the crack growth rate, the crack can propagate asymmetrically due to the presence of residual stress in the specimens, which affects the results. Based on a finite element simulation of crack propagation in a CRB specimen, the severity of the influence is assessed.
343

Kontrola bezpečnostního mechanismu přípojných vozidel / Analysis the safety mechanism of the trailers

Pantůček, Michal January 2019 (has links)
This diploma thesis is engaged in the analysis of a safety mechanism, which is a part of a truck trailer. This mechanism provides a safe and firm connection of a container to the trailer. Primarily abroll containers according to German standard DIN 30 722 are being transported. The introductory part of the thesis deals with the current traffic condition and the accident rate in the Czech Republic. Legislative requirements for safety elements of trailer technology for road transportation are further defined. They are followed by a recherche of industrial solutions for securing mechanisms. Consequently calculations to obtain necessary securing force were performed. An analysis of the mechanism kinematics was carried out then. A structural check of selected mechanism elements was carried out following the kinematics check. Further, an optimalization of a transom design was carried out followed by another structural check. The structural checks were carried out using both the analytical method and the finite element method. In conclusion design documentation was elaborated. This diploma thesis was elaborated in cooperation with the SVAN Chrudim s.r.o.
344

Simulace zápustkového kování pomocí metody konečných prvků / A simulation of closed die forging using finite element method

Nytra, Michal January 2019 (has links)
Tato diplomová práce se zabývá výpočtovým modelováním zápustkového kování, které patří do metod objemového tváření zatepla. Cílem je změnit běžnou praxi tvorby výpočtových modelů ve specializovaných softwarech na bázi metody konečných prvků (MKP) a sestavit výpočtový model v MKP softwaru Abaqus. Pro výpočet jsou zde použity deformační varianta MKP a explicitní algoritmus. Řešenou součástí je ozubené kolo automobilové převodovky. V rámci práce je vytvořena rešerše z oblasti objemového tváření včetně specializovaných programů pro simulace procesů tváření. Dále jsou v práci uvedeny všechny konstitutivní vztahy pro popis elasto-plastického modelu materiálu s tvárným porušením. Následuje teorie přenosu tepla, jsou popsány všechny způsoby jeho realizace s jejich matematickými formulacemi včetně metod řešení. Klíčovou je kapitola popisující postup tvorby výpočtového modelu v softwaru Abaqus od tvorby geometrie až po okrajové podmínky. Následuje analýza dosažených výsledků a práce je zakončena výhledem na možné pokračování v tomto tématu.
345

Konstrukční návrh lineární osy pro těžký obráběcí stroj / Design of linear axis for heavy machine tool

Horák, Miroslav January 2019 (has links)
This diploma thesis deals with the design of linear axis for heavy machine tool. The thesis describes the definition of heavy machine tool and its basic construction nodes. The next chapter describes the components of the linear feed assemblages, the basic principles of use and their advantages and disadvantages. On the basis of this research part there are selected variants of the solution and in the last part of the thesis there is a design of the axis X of the gantry machine tool. Part of the work is a 3D model of the proposed feed assemblages and part of the drawing documentation.
346

Automatizace a optimalizace konstrukce a pracovního procesu horizontální štípačky na palivové dřevo / Automatization a optimalization of desing and proces of firewood horizontal log splitter

Čechman, Jan January 2019 (has links)
Diploma thesis is focused on design and optimalization of log splitter. Thesis consists of search of log splitter types and common used technologies, mechanical design, optimalization, design of propultion system, risk analysis and financial overview. Log splitter is designed to meet needs of automatization. Safety, industrial design and ergonomy has been considered in the design.
347

Návrh testovacího stavu pro dlouhodobé testování spojek určených pro kolejová vozidla / Design of test rig for long-term testing of couplings intended for railroad applications

Machálek, Ondřej January 2019 (has links)
The master thesis deals with design of test rig for long-term testing of coupling appointed to railway vehicles. At first, there is made a brief research which is related to railway coupling used for transmitting a torque. This is followed by an analysis of the most used power devices to derive real loads conditions of tested couplings. There is chosen the most appropriate conception based on made analysis and it is followed by the description of designed components. There is made a verification of modal properties non-purchased components which is necessary part of the thesis. Numerical modal analysis was performed in ANSYS Workbench software. In the end of the thesis there are included stress-strain analysis of the chosen designed components.
348

Návrh ražby a primárního ostění tunelu na stavbě vysokorychlostního železničního spojení / Design of excavation and primary tunnel lining on high-speed railway construction

Dostál, Tomáš January 2020 (has links)
As part of modernization of the Brno-Přerov railway line, is in the section between village Blažovice and town Vyškov desined tunnel composed of two monorail tubes about 640 meters length. Tubes are situated in neogenic clay with an overburden height of 11 meters. This master thesis deals with design suitable tunnel exavation, primary lining with static calculation and geotechnical monitoring.
349

Železobetonová konstrukce bytového domu / Reinforced concrete construction of apartment building

Fusek, Aleš January 2020 (has links)
This diploma thesis deals with the analysis of reinforced concrete structure with masonry walls. Scia Engineer was used for finite element analysis. The spatial models include nonlinear behavior of masonry. Furthermore, the ceiling slab above the 1st floor, beams and columns were designed.
350

Řešení parciálních diferenciálních rovnic s využitím aposteriorního odhadu chyby / A posteriori error estimation method for partial differential equations solution

Valenta, Václav Unknown Date (has links)
This thesis deals with gradient calculation in triangulation nodes using weighted average of gradients of neighboring elements. This gradient is then used for a posteriori error estimation which produce better solution of partial differential equations. This work presents two common methods - Finite elements method and Finite difference method.

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