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Integrity breach analysis of storage tank using FEM
Ševčík, Martin ; Vincour, Dušan (referee) ; Létal, Tomáš (advisor)
This master thesis is focused on computational modelling of critical external as well as internal pressure acting of the repaired tank. During cleaning of pipelines, the gas mixture entered into this storage tank causing loss of integrity in the connection between the roof and the shell. The first part of the thesis is focused on check calculation of the shell in exceptional conditions. The next part describes the repair of the tank including check of the pillar according to ČSN EN 1993 1 1 and ČSN EN 1993-1-6. The main part of the thesis is focused on determination of the buckling resistances of the tank in original as well as repaired state using ANSYS Mechanical software. The results are comparable with original tank, whose buckling resistance was not decreased due to the repair.
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Pressure pipe damage: Numerical estimation of point load effect
Zouhar, Michal ; Hutař, Pavel ; Ševčík, Martin ; Náhlík, Luboš
The most relevant loading conditions for real polymer pipe systems are not only internal pressure, but also loading caused by sand embedding including bending or different kinds of point loads. It has been shown that service lifetime of buried pipes can be reduced especially due to stress concentration caused by external point loads. If the pipe is loaded locally the stress is concentrated here and a crack can initiate at this position or the existing crack can be affected by corresponding stress redistribution. In the paper the effect of the hard indenter, Poisson's ratio, hoop stress level and pipe wall thickness on the crack shape was estimated using numerical simulations of the creep crack propagation based on finite element method. Relation between crack length and crack width was found and expressed by simple relationship. A deeper understanding of the point load effect in order to prevent unexpected failure of the pipelines is of paramount importance for pipeline design.
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Modely dynamické podmíněné korelace a jejich aplikace při mitigaci rizika portfolia
Ševčík, Martin ; Frýd, Lukáš (advisor) ; Nevrla, Matěj (referee)
This bachelor thesis investigates asymmetry in returns of corn, gold and crude oil (both spot and futures) and hedging effectiveness of these commodities when employing DCC family models for hedge ratio estimation. The asymmetry in conditional variances was found to be significant only in case of crude oil spot and futures returns and asymmetry in conditional correlation of spot and futures returns was not shown to be significant in neither of the investigated commodities. With respect to the hedging performance, we conclude that differences in hedging performance measured by hedging effectiveness index are negligible and thus do not support superiority of DCC family models over OLS, which served as a benchmark. Historical Value at Risk, on the contrary, identified the DCC with asymmetry in conditional variance (despite asymmetry not being significant) to be appropriate for corn hedging, however not for the other two commodities, where the OLS based hedge ratio performed similarly or even better than the DCC family models. The main contribution of the thesis thus lays in empirical investigation of asymmetry in returns of selected commodities and testing hedging potential of DCC family based hedge ratio.
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FRACTURE MECHANICS ASSESSMENT OF CRACKED WELDED POLYOLEFIN PIPES
Mikula, Jakub ; Ševčík, Martin ; Hutař, Pavel ; Náhlík, Luboš
The aim of this paper is to present methodology for estimation of fracture mechanics parameters in polyolefin pipes with an axially oriented crack using three dimensional numerical analyses. Linear elastic fracture mechanics is used for description of fracture behavior. In the paper, three different variants of pipe weld with an internal axial semi-elliptical crack are studied. Numerical models correspond to a cracked pipe containing material nonhomogeneity in the welding area caused by welding process. A critical locations of the crack initiated along the pipe wall is found and the stress intensity factor for such cracks with real crack shape are numerically estimated in these critical locations. The methodology presented here can be used for estimation of residual lifetime of welded polymer pipes containing crack.
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Numerical solution of strain and stress components of pressure vessels
Ševčík, Martin ; Lošák, Petr (referee) ; Florian, Zdeněk (advisor)
The bachelor thesis deals with pressure vessels in terms of their definition and categorization. In the following part is carried out an assessment of various types of pressure vessels in terms of their using in engineering, this part is a research study. Further part is focused on solution of deformation and stress of pressure vessel by analytical and numerical way. The part of analytical solution is focused on both membrane and momentum shell. Numerical solutions are made by FEM in calculation software Ansys Workbench 16.2.
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Racing Game in 3D
Ševčík, Martin ; Láník, Aleš (referee) ; Šuška, Boris (advisor)
This bachelor's thesis describes issues of interaction between Java Monkey Engine (jME) and models created with program Autodesk 3D Studio Max. It contains theoretical basis for the jMonkey Engine architecture and Lightweight Java Game Library (LWJGL). In the following section, the thesis describes techniques of working with objects in the 3D scene and their way of implementation.
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Wireless sensor network
Ševčík, Martin ; Fedra, Zbyněk (referee) ; Prokopec, Jan (advisor)
This bachelor thesis deal with the ZigBee wireless technology and design of a simple sensor network on its principle. The network is designed for a smaller apartment. As the temperature sensor is used DS1631 thermometer. Communi-cation of the coordinator with the computer ensures XPort®. Used modules from the Meshnetics company integrates the AVR processor and the radio transmitter / receiver at 2.4 GHz operating frequency.
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3D Racing Game For Android Platform
Ševčík, Martin ; Polok, Lukáš (referee) ; Láník, Aleš (advisor)
This master's thesis deals with the possibilities of using open source 3D game engine Java Monkey Engine (jME) in developing applications for the Android platform. It includes theoretical knowledge for the jMonkey Engine architecture and the Android platform. In the following section, the thesis describes used techniques and external libraries in solving issues of interaction between jME and Android platform and of working with objects in the 3D scene and their way of implementation.
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