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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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Development of methods for analysys road safety barriers in terms of dynamic effects
Koudelka, Ivan ; Krejsa,, Martin (referee) ; prof. Ing. Alois Materna, CSc., MBA (referee) ; Salajka, Vlastislav (advisor)
The presented work analyses the methodology and approach of the legislation. It presents in the press presented results of numerical modelling of the impact of vehicles crashed into barriers that are being solved in the Czech Republic and worldwide. It presents a recommendation of a methodology for assessing crash barriers. The methodology follows the basic principles used in the TP 101 and EN 1991-1-1. The kinetic energy of the vehicle at the moment of impact is replaced with substitute static force, whose effects are comparable with those of a vehicle collision. The supporting structure of crash barriers is implemented in compliance with means of statics. The calculation includes the vehicle deformation, which represents the real distribution of the energy absorbed by the deformation of the vehicle and the energy that crash barriers need to absorb. The proposed methods allow to take into account non-linear behaviour of the structure both in terms of geometry and in terms of material nonlinearity. The work also deals with the interpretation of various types of support structures in the computational model. A specific case is used for a demonstration of a way of modelling the elastic supporting column of crash barriers in the soil, or modelling the friction of a loose concrete block over the surface. To ensure the proper position of interconnected loose blocks corresponding to the reality, a method of modelling the place of a possible contact of the breakthrough is drafted. A significant contribution to the more accurate calculation is achieved by sequential increase of the load on the construction by using load increment and measurement of energy increases absorbed by the deformation in each step. The presented methodology is an effective tool to assess crash barriers. For the application of this tool, using common resources and facilities available to almost every designer dealing with statics of structures is sufficient. In conclusion, the knowledge obtained fr
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Study of impact of a transport vehicle into a structure.
Sychrová, Šárka ; Salajka, Vlastislav (referee) ; Němec, Ivan (advisor)
Master's thesis deals with the analysis of the impact of transport vehicle on a building structure. Transport vehicle is represented by an airliner and building structure is represented by a containment of a nuclear power plant. The aim of thesis was to explore the possibility of numerical simulation of an impact of transport vehicle on a building structure utilizing the RFEM program and evaluation of the damage extent.
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Actions on bridges caused by the water flow and floating items
Řezník, Jindřich ; Duchan, David (referee) ; Špano, Miroslav (advisor)
The subject of this thesis is the enumeration and analysis methods applicable to the calculation of loads on bridges from water and water-borne objects. It involves a hydrodynamics loads, loads from captured debris and from impacts of the individual water-borne objects and their clusters. It includes an assessment of the current situation, the teoretical analysis and model calculations on the concrete bridge with the evaluation of usable methods.
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Simulator for check of seat belts function
Neuwirth, Zdeněk ; Prášil, Ludvík (referee) ; Mazůrek, Ivan (advisor)
Thesis is oriented on project construction universal apparatus for introduction and research effects deceleration and impact with possibility setting initial velocity. Basic application proposed test station is crash simulation for diagnostic safety belts. At first there're in work presented physical value that describe action in progress at impact, further safety belts, their testing and test . Considerable volume of work is devoted to project actuation, system obstruction kinetic energy and basic construction. Subsequently is presented proposed construction and performed strenght calculation. In the end there are summarized basic characteristics proposed construction, short financial opinion, process of installation and safety rules for using this equipment.
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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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Bird mortality at transparent barriers
Houdová, Monika ; Reif, Jiří (advisor) ; Koleček, Jaroslav (referee)
Bird mortality at transparent barriers (noise barriers or common house windows) is undoubtedly very important environmental issue, because of the rapid development of human society and even more rapid growth of very dangerous places for birds. At this time there is no review article yet, that would synthesize each sub-study on the extent to which individuals can die on those obstacles, which factors are critical for the ability of obstacle avoiding, how much collision threaten the vitality of bird populations and if we can prevent such unintended damage. This bachelor thesis handle with these questions as a literary review. From the available information we can suggests that the most important factor is migration behavior of birds, individuals migrating through the night are much more at risk than those migrating during the day, mostly because of light pollution, which can confuse them. The most dangerous time of year in this direction is clearly autumn, and that also relates with migration. Population losses caused by collision to the transparent barriers can be up to 20 % of the total population per year. Thesis in addition to a summary of available information on the issue proposes and evaluates possible preventive aplications, which may further serve to effective conservation for birds among...
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The absolute I and the conception of knowledge in the philosophy of J. G. Fichte
Kollert, Lukáš ; Karásek, Jindřich (advisor) ; Landa, Ivan (referee)
This bachelor thesis outlines basic features of object-consciousness and tries to show that it must be grounded in a "consciousness" of another type, which doesn't have the structure (non-identity of subject and object) characteristic for the consciousness of an object. The pre- reflective relation of the self to itself or immediate "consciousness" of the self is identified as a basis enabling self-(re)cognition in reflexion. The next step puts forward one of reasons to ascribe this relation of the self to itself to the self-positing absolute I (here the absence of subject-object difference is typical). The fourth chapter addresses questions concerning the possibility to explain the object-consciousness and the presence of manifold in the I from the standpoint of unlimited and self-identical absolute I. It further distinguishes several forms of realism and idealism rejected by Fichte himself and follows the course leading to Fichte's own position, i. e. real-idealism or ideal-realism. Finally, the text discusses in detail the concept of "check" (Anstoß), which is understood as one of the key concepts of the early science of knowledge. Key words: Fichte, science of knowledge, self-consciousnes, object-consciousness, absolute I, check, idealism, realism, sensation, reflection
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Bird mortality at transparent barriers
Houdová, Monika ; Reif, Jiří (advisor) ; Koleček, Jaroslav (referee)
Bird mortality at transparent barriers (noise barriers or common house windows) is undoubtedly very important environmental issue, because of the rapid development of human society and even more rapid growth of very dangerous places for birds. At this time there is no review article yet, that would synthesize each sub-study on the extent to which individuals can die on those obstacles, which factors are critical for the ability of obstacle avoiding, how much collision threaten the vitality of bird populations and if we can prevent such unintended damage. This bachelor thesis handle with these questions as a literary review. From the available information we can suggests that the most important factor is migration behavior of birds, individuals migrating through the night are much more at risk than those migrating during the day, mostly because of light pollution, which can confuse them. The most dangerous time of year in this direction is clearly autumn, and that also relates with migration. Population losses caused by collision to the transparent barriers can be up to 20 % of the total population per year. Thesis in addition to a summary of available information on the issue proposes and evaluates possible preventive aplications, which may further serve to effective conservation for birds among...
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