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Prestressed bridge on the expressway
Juřenčáková, Jana ; Zlatuška, Karel (referee) ; Koláček, Jan (advisor)
The purpose of the diploma thesis is to design a expressway bridge over the river Vsetínská Bečva. The bridge is located between Valašské Meziříčí and Vsetín. Separate superstructures are designed for each directions of the expressway. The right superstructure, which is wider, is considered for detailed design. Two variants were proposed, A double T beam superstructure and a box girder superstructure. The three span box girder superstructure was chosen for the design. Spans are 48+65+48 m long. Two options of construction process of the superstructure were proposed. This bridge is designed according to the limit states, the influence of construction process is considered. Structural models of construction were made as a finite element model and a plate model. Structural analysis, drawings and visualization were developed.
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Oxide scales damaging evaluation
Audyová, Markéta ; Vejvoda, Stanislav (referee) ; Lošák, Pavel (advisor)
This work is focused on oxide scale failure and characteristics created in high temperature – supercritical processes. The presence of high temperature corrosion in supercritical processes is minimalised by selection of the right material. For this work was selected material X10CrMoVNb9-1, where formulas of present oxidation scales are Fe2O3, Fe3O4 and FeCr2O4. Each oxidation scale has its own mechanical properties thus it is important to notice scale arrangement, thickness and geometry. Oxide scale mechanical properties, scale failure mechanisms and oxidation scale growth is evaluated in this work. Tension and pressure oxide scale failure are determined by critical values, which are mentioned in this work. Thanks to these values there was possibility to verify the authenticity of the finite element model. Oxidation scales created in heat exchangers are badly accessible thus it is difficult to observe them or remove them mechanically. Tube finite element model with oxidation scales was created in this work. There are simulations of scales on selected steel in supercritical conditions (pressure 24 MPa, temperature 500 °C). Simulation and analytic results are compared. Failure operative conditions are searched for scale FeCr2O4 until its compleate delamination and separation from metal. Aim of this work is to create an oxidation scale model with a possibility of futher use.
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Numerical Analysis of BFRP Reinforced Concrete Slab Exposed to Impact Loads
Jindra, Daniel ; Hradil, Petr
This paper describes numerical analysis utilizing the FEM of a simply supported concrete slab exposed to close range explosion of TNT charge. Reinforcing bars are made of basalt fibre reinforced plastic (BFRP). 3D numerical model has been created, and a software with explicit solver has been used in order to conduct analyses. A simplified method of the blast loading modelling has been utilized. Several cases with different mesh size or finite element formulation are considered. The results are compared with experimental data.
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Prestressed bridge on the expressway
Juřenčáková, Jana ; Zlatuška, Karel (referee) ; Koláček, Jan (advisor)
The purpose of the diploma thesis is to design a expressway bridge over the river Vsetínská Bečva. The bridge is located between Valašské Meziříčí and Vsetín. Separate superstructures are designed for each directions of the expressway. The right superstructure, which is wider, is considered for detailed design. Two variants were proposed, A double T beam superstructure and a box girder superstructure. The three span box girder superstructure was chosen for the design. Spans are 48+65+48 m long. Two options of construction process of the superstructure were proposed. This bridge is designed according to the limit states, the influence of construction process is considered. Structural models of construction were made as a finite element model and a plate model. Structural analysis, drawings and visualization were developed.
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Dynamic and heat transfer analysis of a container with measuring instruments for space probes
Zolotarev, Igor ; Bula, Vítězslav ; Šnábl, Pavel ; Gabriel, Dušan ; Dobiáš, Jiří ; Masák, Jan ; Snížek, Jan ; Souček, Jan
Rocket boosters and spacecraft are subject to intense acoustic environments during launch, which induce high levels of vibration in structural elements and equipment. In addition, elastic structural interactions with propulsion systems and flight control systems can produce low-frequency, high-deflection flight instabilities. Natural vibration of the container with measuring equipment were studied by numerical and experimental methods in the laboratory of Institute termomechanics CAS. Heat transfer analysis inside the container was made by FEM with respect to the conditions during start of the rocket and work in space.\n
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Oxide scales damaging evaluation
Audyová, Markéta ; Vejvoda, Stanislav (referee) ; Lošák, Pavel (advisor)
This work is focused on oxide scale failure and characteristics created in high temperature – supercritical processes. The presence of high temperature corrosion in supercritical processes is minimalised by selection of the right material. For this work was selected material X10CrMoVNb9-1, where formulas of present oxidation scales are Fe2O3, Fe3O4 and FeCr2O4. Each oxidation scale has its own mechanical properties thus it is important to notice scale arrangement, thickness and geometry. Oxide scale mechanical properties, scale failure mechanisms and oxidation scale growth is evaluated in this work. Tension and pressure oxide scale failure are determined by critical values, which are mentioned in this work. Thanks to these values there was possibility to verify the authenticity of the finite element model. Oxidation scales created in heat exchangers are badly accessible thus it is difficult to observe them or remove them mechanically. Tube finite element model with oxidation scales was created in this work. There are simulations of scales on selected steel in supercritical conditions (pressure 24 MPa, temperature 500 °C). Simulation and analytic results are compared. Failure operative conditions are searched for scale FeCr2O4 until its compleate delamination and separation from metal. Aim of this work is to create an oxidation scale model with a possibility of futher use.
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Efekt velikosti částic na lomové chování polypropylenového kompozitu
Nezbedová, E. ; Knésl, Zdeněk ; Hutař, Pavel ; Majer, Zdeněk ; Veselý, P.
The addition of mineral fillers to polypropylene (PP) can profoundly change the mechanical properties of polymer system. The properties of the particles themselves (size, shape, and material properties) can have significant effect on the global behaviour of composite, particularly on its toughness and stiffness. This contribution is focused on effects of particles size and their density on fracture toughness of polyprophylen particulate composite. The effect was studied from the experimental as well as from the theoretical point of view. The change of fracture toughness was estimated with utilisation of linear elastic fracture mechanics approach. The composite was modelled as a three-phase material with homogeneously distributed coated particles and numerically simulated using the finite element program ANSYS.
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