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Study of the Chaboche´s plasticity model complexity influence on the stress and deformation at the high pressure vessel
Paraska, Boris ; Obdržálek, Vít (referee) ; Vrbka, Jan (advisor)
The main aim of this thesis is to define material parameters of Chaboche model of plasticity. Adjustment of the parameters has to correspond to the experimental datas. These datas are represented by an uniaxial strain controlled test curve for fewer than two cycles and also by cyclic stress-strain curve. After that, an cyclic tension-compresion test for various parameters of Chaboche´s model of plasticity is simulated in an ANSYS software. Finally, the most suitable configuration of Chaboche´s model of plasticity is used for cylindrical thick-walled body. Cylindrical body represents a simplified model of high-pressure tank of fuel (diesel) – rail in Common Rail system.
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New devices for diagnostics of historical structures
Hasníková, Hana ; Kloiber, Michal ; Zíma, Pavel
The aim of the paper is to present a few new devices that were developed at ITAM AS CR for non-destructive testing of materials, especially those from historically valuable structures. So called microtube is a semi-automatic portable tool for water absorption measurements. It consists of box with microprocessor where the time is recorded and the plastic “pistol” – a part that is in contact with the material surface and where the scaled micro-tube is fixed on. The natural stones, mortars and other porous materials can be measured by the microtube; it is very useful to assess the efficiency of various hydrophobic treatments used within the restoration. The diagnostic device for in-situ assessment of timber in existing structures enables direct determination of conventional compressive strength and modulus of deformability in arbitrary depth along timber profile. The semi-destructive method causes a very gentle damage on the structural members.
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Problems of motions and deformations at the undermined territory
Doležalová, Hana
Underground mining leads to creation of subsidence depression. In the contribution measuring of motions and deformation using GPS technology is presented. Surveying on the geodetic points of the subsidence depression usually has to be done on a large area in a short time. That's why we use GPS mesuring, but also this has to be adapted to the changing surface of the undermined territory. The point coordinates are then used to compute the size and direction of motions and deformations that happen in the subsidence depression.
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Solution of Engine Block Deformations during Assembling
Foltis, Aleš ; Píštěk, Václav (referee) ; Novotný, Pavel (advisor)
Size and distribution of mount deformation are the main topics discussed in this thesis, using different static loading. The thesis’ primary focus is to show how deformation and stress of the engine block with cylinder liner are affected in the assembly order of the cylinder head. The calculation and evaluation of the solution are calculated by using method finite element, software Ansys. In addition other methods are discussed which can also measure the deformation of the engine block.
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Studium struktury a magnetismu FeCo při vysokých deformacích z prvních principů
Čák, Miroslav ; Legut, Dominik ; Šob, Mojmír
Total energies and magnetic moments of FeCo along the tetragonal deformation path are calculated using first-principles electronic structure methods. Total energies are displayed in a contour plot as a function of tetragonal distortion and volume; borderline between the ferromagnetic and nonmagnetic states is shown. The calculated energies may be used to predict the lattice parameters of FeCo thin films on various (001) substrates; here we study the FeCo film on the MgO(001) substrate. The calculated results are compared with available experimental data. The loss of magnetism of FeCo at low atomic volumes and large shape deformations is observed.
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Deformation measurement of motorcycle components
Augste, Jan ; Novotný, Tomáš (referee) ; Tůma, Zdeněk (advisor)
The task of this diploma thesis is technical solution for deformation measuring of motorcycle components. By reason of the technical discretion, technology of measurement was changed to another, using image processing. Retrieval which describes fundamental principle of method named photogrammetry and the main conditions of measuring. For a practical testing the carbon composite tube of main motorbike fork was used. It was loaded a with a bending moment. Due to measuring technology was changed, so the design of loading bench was change too. In the end of diploma thesis is appreciation of practical experience discovered in writing of this thesis.
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Reference temperature prediction from tensile test parameters
Šmida, T. ; Babjak, J. ; Dlouhý, Ivo
Reference temperature of fracture toughness temperature diagram has been predicted based on tensile test data. Neuron analysis was applied to solve these properties correlation. For fracture toughness determination three-point bend specimens have been applied, the reference temperature being calculated applying multi-temperature method. Different strength and deformation properties have been evaluated from standard tensile specimens focusing on data from localised deformation during specimen necking. Totally 29 data sets from low alloy steels have been generated for the analysis. Good correlation of predicted and experimentally determined values has been found. Further analysis with higher number of data sets is needed to increase the accuracy of predicted values and decrease the number of input data.
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