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Static analysis of pedestrian bridge stucture
Holada, Jiří ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The thesis is focused on a static analysis and compiling a computational model of the suspension bridge for pedestrians and cyclists over the Sázavu river in Zbořený Kostelec vilage. The model is constructed according to the real shape of the structure. The length of the footbridge is 135 m and width 4 m. The calculation and compiling a computational model is processed by program ANSYS free Student Software.
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Detail analysis of complex connection in the structure
Hokeš, Filip ; Hradil,, Petr (referee) ; Kala, Jiří (advisor)
The main objective of the thesis is to find and describe dependence between load carying capacity of a pin connection and a pin hole drilling. The dependence will be made in according to standard ČSN EN 1993-1-8, by theoretical solution and finally by finite element method in the ANSYS system. The second objective of the thesis is focused on a verification of load test results by numerical methods. Numerical solution will be made up in two analysis with different types of finite elements. The most fiiting model will be used as a basis for description of the relationship between capacity and diameter of drilling.
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Wind load analysis of building structures
Ptáček, Václav ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
This bachelor’s thesis is focused on wind load analysis with regard to the dynamic effects caused by wind impact on slender structures. These calculations are conducted for a chimney structure with use of various wind velocities. The thesis includes basic principles of fluid flow modeling in CFD programs like ANSYS CFX.
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Statics, dynamics and kinematics of multibody contacts
Štekbauer, Hynek ; Kala, Jiří (referee) ; Krejsa, Martin (referee) ; Němec, Ivan (advisor)
The dissertation deals with the problem of dynamic contact and kinematic constraints between various entities and the related issues of its implementation for static and dynamic finite element analysis. The reason for the development in this area is the increasing demands on functionality of FEM softwares and also accuracy and performance of computational models. Firstly, the problem of enforcing contact conditions in explicit dynamics is addressed. New methods are proposed with respect to the stability of the explicit time integration scheme so that there is no need to reduce the computational time step, adjust the input variables or solve a large system of equations. These methods are based either on basic kinematic principles or on the energy conservation law. Furthermore, attention is paid to different types of constraint conditions having a wide application in civil engineering practice. Understanding them is the starting point for the subsequent definition of the newly designed finite element of the pulley. The correctness of all theoretically proposed methods and their implementation is demonstrated by numerical examples.
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Simulation of nonlinear response of construction materials and problem of identitifaction of material parameters
Hokeš, Filip ; Kala, Zdeněk (referee) ; Krejsa,, Martin (referee) ; Kala, Jiří (advisor)
The issue of parameter idenetification within numerical simulations can be considered a necessary step in the use of mathematical models, such as complex material models of building materials utilized in finite element method. The problem is particularly epmhasized in the case of anisothropic materials but also in the case of concrete, which behaves differently in tension and compression and which shows different response under rapid-dynamic and long-term loading. Correct capture of the concrete response in the computation requires usage of plasticity theory, damage theory, visco-elasticity and visco-plasticity or their mutual combinations. It results in development of material models and rheological schemes with large amount of parameters that are not commonly available in standards. The disseration presents application of meta-heuristic algorithm Particle Swarm for parameter identification. The success of the method is demonstrated in a pair of cases, first on the identification of elastoplastic material model parameters from stress strain diagram and then to identify the values of stiffness constants and viscosities of the rheological scheme from a creep curve.
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Smoothed Particle Hydrodynamics in Structural Dynamics
Hušek, Martin ; Králik,, Juraj (referee) ; Maňas,, Pavel (referee) ; Kala, Jiří (advisor)
The focus of the thesis is on the application of the Smoothed Particle Hydrodynamics (SPH) method in structural dynamics with an emphasis on usage of quasi-brittle materials. The first part is focused on the introduction, history, and theoretical background of SPH. Numerical examples in which strengths and weaknesses of SPH are shown follow. In addition to pure SPH models, several coupling approaches with the Finite Element Method (FEM) are also discussed. After the introduction of SPH, the focus is on quasi-brittle materials and their reinforced variants. The numerical concept and mathematical background of the Continuous Surface Cap Model are outlined, several benchmarks are presented. Strain-rate effects and their impact on pure SPH and coupled SPH-FEM models are evaluated next. In this section, the author proposes a new approach for SPH models reinforcement with FEM beam elements. The coupling approach was named sublayer coupling and shows a potential in simulations while the SPH tensile instability is alleviated. Since concrete is often associated with heterogeneity and very specific material structure, a unique algorithm for concrete structure generation in combination with SPH is proposed in the next chapter. The concept is based on utilization of coherent noise functions which can bring a variability to numerical models. It has been proved that the algorithm is robust, stable, and easy to implement into the SPH framework. With regard to that, the so-called numerical heterogeneity, a concept of parameters variability implementation, is introduced together with examples. The last part of the thesis is dedicated to the application of SPH in real experiments. The first experiment focuses on a high velocity impact. The second experiment deals with an explosion in which the focus is on both the loaded specimen and charge. Since SPH simulates the explosive, detonation products, and the loaded specimen, it is a fully coupled fluid-structure interaction simulation.
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Analysis of railway behavior on vehicles effects
Peňázová, Gabriela ; Kala, Jiří (referee) ; Salajka, Vlastislav (advisor)
The master’s thesis deals with the possibilities of railway track modeling. The computational models were created in ANSYS Classic. Simplified 2D model represents a longitudal half of classic single track construction, 3D models represent classic single track construction and RHEDA 2000 slab track. Static and dynamic response of 2D model was compared with analytical solutions by Timoshenko and Fryba. Static and dynamic responses of 3D models were analyzed and compared.
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Static analysis of pedestrian bridge stucture
Holada, Jiří ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The thesis is focused on a static analysis and compiling a computational model of the suspension bridge for pedestrians and cyclists over the Sázavu river in Zbořený Kostelec vilage. The model is constructed according to the real shape of the structure. The length of the footbridge is 135 m and width 4 m. The calculation and compiling a computational model is processed by program ANSYS free Student Software.
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Determination of fire resistance of structures
Jindra, Daniel ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
Possibilities of modeling non-linear behavior of concrete within standard room temperatures and increased fire-load values using FEM software ANSYS are studied. Temperature dependences of material models are considered. Fire resistance of reinforced concrete and concrete-steel composite construction is analyzed. Fire loads are defined in accordance with relevant standards. Non-linear structural transient analyses are calculated after temperatures were determined by transient thermal analyses. Results obtained from analyses of simple reinforced concrete structure are compared with approach of isotherm 500 °C method.
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Static analysis of bridge construction: Černý most in Hodonín
Okánik, Michal ; Kala, Jiří (referee) ; Sobek, Jakub (advisor)
The diploma thesis deals with static analysis of the Black bridge in Hodonín city. The creation of the numerical model in ANSYS sw. is described according to the existing project documentation, followed by the application of loading and boundary conditions (including the solution of foundation soil placed on the piles). The selection of the loading is used according ČSN EN standards for analysis and verification of the main construction parts. This work also includes verification of the piles deformations calculated both in ANSYS sw. and by the direct stiffness method (MS Excel is used) and their comparison is done. Amongst other attachments, the verification of the load carrying capacity of the structure (respecting the current traffic limitation allowing only one vehicle to be on the bridge structure) is also provided.
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