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Determination of input parameters of advanced soil constitutive models using optimization methods
Koudela, Pavel ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
Choice of the constitutive model and determination of input parameters are necessary for a successful application of numerical methods in geotechnical engineering. Higher complexity of modern constitutive models results in an increase of the number of input parameters and time requirements for their calibration. Optimization methods are a possible solution for this problem. An application in which metaheuristic optimization method Particle swarm optimization (PSO) is involved is presented in this thesis. Critical review and testing of various PSO alternatives was performed in the first part of this thesis. The most efective PSO alternatives were chosen. In the second part connection between PSO algorithm and finite element solver was prepared. Automatization of determination of constitutive models input parameters was performed on three boundary value problems: laboratory test (oedometer), in-situ test (pressuremeter) and geotechical construction (retaining wall). Three types of constitutive models are used. Linear elastic-perfectly plastic Mohr-Coulomb model, elastoplastic non-linear Hardening soil model and Hardening soil - small strain model.
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Design of retaning structure in the Brno- sever district
Koporec, Vladimír ; Koudela, Pavel (referee) ; Miča, Lumír (advisor)
The bachelor's thesis deals with the design of the sheet pile construction of the construction pit of the underground car park of a multifunctional house in Brno and its impact on the adjacent tunnel. The design and assessment of the sheet pile structure is developed on the basis of the results obtained in the GEO5 program. For a more detailed analysis of the impact of the proposed sheet pile structure on the adjacent tunnel, a numerical analysis is performed in the PLAXIS 2D program. As part of this analysis, a study of the influence of the material model (Mohr-Columb, Hardening soil and Hardening soil small) on the change of deformations and internal forces in the tunnel is made. The results of the work show the interaction between the proposed structure and the tunnel.
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Utilization of cone penetration tests in the load-transfer method for bored large diameter piles
Štetiar, Juraj ; Koudela, Pavel (referee) ; Chalmovský, Juraj (advisor)
This thesis is focused on the use of the results of cone penetration tests and the method of transfer functions for the design of drilled large-diameter piles. The introductory part clarifies the theoretical basis of cone penetration testing, method of transfer functions, various material models and the regression coefficients in the nonlinear method of pile settlement calculation. The theoretical introduction will be followed by other chapters in which the theory is applied to specific practical cases. The third part consists of geotechnical interpretation of the results of two static load tests in two different localities using graphical and numerical outputs (limit load curves, force distribution along the length of the pile, dependences of displacements and deformations on the pile depth, shaft frictions and more). The next part deals with the evaluation of the CPT at the site of the load test and the compilation of the calculation profile at the site based on the obtained data. In the fifth part there will be an inverse analysis of load tests using the method of transfer functions in the software developed at the Institute of Geotechnics, Faculty of Civil Engineering, Brno University of Technology. An inverse analysis of load tests using finite elements method and obtained data from the CPT can be found in chapter 6. Within this analysis, several material models will be applied and compared to the issue. This analysis will be followed in the fifth part by a comparison of direct correlation methods for determining the ultimate pile shaft friction from CPT data with the results of inverse analysis by MTF to determine the most suitable method. Finally, from the obtained data the regression coefficients will be adjusted for the calculation of the second limit state of lone piles by a nonlinear method (according to Masopust).
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Experimental and Numerical Analysis of the Volume Changes of Fine-grained Concretes
Odstrčil, Štěpán ; Frantík, Petr (referee) ; Kucharczyková, Barbara (advisor)
This diploma thesis deals with the experimental and numerical analysis of volume changes of fine-grained concrete. Experiments were carried out, measuring both the length changes as well as the mass losses and the internal temperature of the test specimens made from fine-grained concrete. The measurements were divided into two parts (phases). The first phase took approx. 72 hours. The second phase was focused on the long-term measurements and will be completed after stabilization of the mass losses and length changes. In the diploma thesis, the first phase of measurement was elaborated in detail, both in terms of experimental and numerical analysis. In addition, a C # .NET program was created to facilitate the processing of raw measurement data from the data logger. Finally, a comparative calculation was performed according to the model B4, where the result of the calculation was compared with the results of the experiment.
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Hygrothermal processes in walls of wooden houses
Vencel, Lukáš ; Vlach, František (referee) ; Bečkovský, David (advisor)
This diploma thesis solves the problems of hydrothermal processes in walls of wooden houses and associated issues. A chosen were two apartment buildings, where they underwent exmerimental measurement of indor air, in order to determine the boundary conditions commonly boundary building evelope. Was followed by hygrothermal analysis of four commonly used constructions of wooden buildings in the Czech Republic, using various numerical methods. The quantity of information obtained from various numerical methods were analyzed individually. The final part of the thesis is devoted to experimental measurements of diffusion properties of materials. Namely foil vapor barrier, in terms of its influence on the perforation vapor diffusion resistance factor. Information obtained from the experiments were applied to re numerical analysis for walls with a foil vapor barrier. Followed by comparing both cases, in terms of changes hygrothermal behavior of structures with influence of perforation of the vapor barrier.
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Experimental study of reinforcement in light-weight concrete components
Lisztwan, Dominik ; Kocáb, Dalibor (referee) ; Vymazal, Tomáš (advisor)
This bachelor thesis describes the experimental comparison of behaviour of reinforced lightweight concrete panels. Panels are reinforced with traditional steel grid and basalt composite reinforcement. The comparison of results is based on set of data from static load tests. The results of load test are also compared to the results made with nonlinear numerical analysis by finite element method and also calculation by hand. A part of this thesis includes determination of physical and mechanical properties of used concrete.
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Experimental and numerical analysis of reinforced concrete elements
Niedoba, Jakub ; Láník, Jaromír (referee) ; Žítt, Petr (advisor)
This master‘s thesis deals with the behaviour of strengthened reinforced concrete beams. The aim was to evaluate different types of strengthening in comparison not only with each other, but also with the reference beam. Three reinforced concrete beams were fabricated for the purpose of the thesis. The first served as a reference beam, the second was strengthened with carbon lamella glued to the lower edge of the reinforced concrete beam, and the last one was strengthened with unbonded post-tensioning system. Subsequently, they were all loaded by a four-point bending. An evaluation was then carried out which shows that the two strengthened reinforced concreate beams resist the load much better than the reference beam. In the conclusion, different utilization possibilities of both methods are listed, as well as the disadvantages that must be taken into account when designing.
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Numerical analysis of the lightning on small aircraft
Krutílek, David ; Ochodnický, Ján (referee) ; Dražan, Libor (referee) ; Raida, Zbyněk (advisor)
This dissertation deals with the numerical analysis of effects of a lightning strike on an aircraft and with the design of the optimal composition of the composite structure in terms of lightning strike protection. When optimizing the composition, a simplified model of the composite nose section of an EV-55 aircraft is used. The optimization of the composite structure is based on results of experimental measurements and testing. On the simplified model of the nose part, the material composition of the composite is verified and the direct and indirect effects of the lightning discharge are numerically estimated
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Equivalent circuit realizations of the simple chaotic oscillators
Kobza, Jaromír ; Dostál, Tomáš (referee) ; Petržela, Jiří (advisor)
The aim of this paper is to introduce with basic theory the problems encountered when considering the circuit implementation of autonomous RC chaotic oscillator with nonlinearity. All oscillator prototypes are based on one type of universal oscillator circuit. This circuit is able to generate a lot of attractors on condition of different entrance parameters. The design is based on a mathematical simulation, which includes the generation of electronic circuit values. The work is focused the transformation of these values to operational circuit configuration and simulation in a circuit simulator. The final task is to acquire chaotic attractors. Oscilloscope and spectrum analyser photos will verify the operation.
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