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Development and application of computational model of ballistic resistant composite laminate
Urbášek, Jan ; Kubík, Petr (referee) ; Petruška, Jindřich (advisor)
This master thesis is aimed at computational modeling of ballistic resistant layered laminate. The introductory sections of the thesis are aimed at understanding the individual topics that are closely related to the interaction of the projectile and target and computational modeling of this process. The main goal of this thesis was to create a computational model that is able to reflect the behavior of aramid fabric during the interaction with the projectile. During the development of the computational model were used more methods of modeling and also more material models were used. For the purposes of the development of the computational model were used the available data of the companies SVS FEM s.r.o. and VVÚ s.p. The outcome of the diploma thesis is a computational model of aramid fabric which is designed for ballistic protection simulations. This model is validated on the basis of available experiments. The validated computational model is then applied to the simulation of ballistic protection.
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Application of DIC method in residual stress measurement using hole drilling method
Kováříková, Sabina ; Kubík, Petr (referee) ; Návrat, Tomáš (advisor)
This thesis deals with measurement of residual stress by hole drilling method. This method is based on drilling a hole and measurement of deformation in the area around this hole. Measured deformations are then converted to residual stresses by using calibration coefficients. The deformation around the drilled hole is measured by optical non contact method called digital image correlation (DIC). First part of the thesis is focused on current state of research. The thesis contains evaluation of residual stresses by using different methods and evaluation of used methods.
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Design and examination of parameters of the line stock loop for sheet metal processing
Novák, Tomáš ; Šebek, František (referee) ; Kubík, Petr (advisor)
Master thesis is focused on determination of stress and deformation state of metal sheet in stock loops of non-standard dimension. The main goal was creating numerical model and de-termination of maximal possible stock of metal sheet for all requested parameters. The problem was solved using Finite element methods in the software ANSYS. Results were handed to ŽĎAS, a.s. corporation, where they will be used for design of the lines for metal sheet proces-sing of non-standard dimension. Another goal was estimation, how the residual stress in metal sheet can effect the observed stress state.
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Empirical relationships for the assessment of the small punch test
Venský, Jiří ; Kubík, Petr (referee) ; Šebek, František (advisor)
This thesis aims at describing the small punch test, considering its limitations and its applications. Research of empirical equations, by which the value of yield stress and ultimate tensile stress is determined, was carried out. Furthermore, four calculation models were introduced. These models served to establish the yield stress of two materials using analytical solution based on Kirchhoff´s theory of plates. Calculated values of the yield stress were compared to the values obtained by the normalized tensile test. Calculated values were compared to the values of yield stress from the empirical equations found in literature as well. Yield stress values obtained by empirical relations were more accurate than those obtained from analytical solutions stated in this thesis.
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A simulation of closed die forging using finite element method
Nytra, Michal ; Šebek, František (referee) ; Kubík, Petr (advisor)
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.
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Design of the structural modifications for mitigating the consequences of the car frontal crash into the rigid barrier
Hošek, Štěpán ; Kubík, Petr (referee) ; Šebek, František (advisor)
There are many collisions on the roads every day. Automotive companies do number of different types of crash-tests to reduce the consequences of these collisions. Crash-tests are supposed to uncover problems of tested vehicles. Then it is possible to propose constructional changes to reduce the consequences of different types of collisions. Indipendent organisations then test productional vehicles according to their standarts and evaluate safety of these vehicles. One of these crash-tests is the small overlap test which is being done by Insurance Institute for Highway Safety. The small overlap test will be the subject of this thesis. Computational modelling of small overlap test is realised for basic variant and for variants with changes. There is also comparison of basic variant and variants with changes.
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A verification of an approximation of the continuous double auction by a sequence of call auctions.
Kubík, Petr ; Šmíd, Martin (advisor) ; Branda, Martin (referee)
The thesis deals with two kinds of double auction - with the continuous auction and a sequence of call auctions. We explain their rules and we define their models. We present results of simulations of the both kinds of double auction - the aim is to look for the call auction with such parameters that the prices and the traded volume of the continuous auction are approximated best. Finally, in a theoretical part, we characterize the dis- tribution of the order book in the continuous auction and then we specify the joint distribution of the price and the traded volume in the call auction (the distribution of bid, ask and the traded volume given by the continuous auction may be immediately devised from the distribution of the order book).
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Analysis of influence of geometric deviations of semifinished product on following bending process
Anděl, Tomáš ; Kubík, Petr (referee) ; Vosynek, Petr (advisor)
Presented diploma thesis was created in cooperation with Siemens s.r.o., and deals with the analysis of the bending of aluminium sheets which are later used as a conductors of high voltage electrical energy. These parts are completed into assemblies which serves as connectors of particular segments of an electrical network. The problem occurs as a result of incorrect bend, because it is impossible to join these sections properly. The customer would like to verify if the defined tolerances of semi-finished products are sufficient for proper bend and in case they are not, the tolerances should be modified. Due to the requirement for running numerical simulation in one of the open source software, the Salome-Meca program environment was used.
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