|
|
Three-dimensional Spring Networks and Their Applications
Štafa, Michal ; Brožovský, Jiří (referee) ; Keršner, Zbyněk (referee) ; Frantík, Petr (advisor)
The presented work highlights the remarkable potential of physical discretization – lattice model FyDiK in three-dimensional modelling of non-linear problems in structural mechanics. To achieve the objectives a software application, that implements the model FyDiK along with the 3D graphical user interface has been developed and thus is able to assemble a spring network model. Such a model was used for modelling the formation of cracks and fracture in the concrete specimens and also to model a plastic behaviour of steel I-beam. The calculations were performed by a massive parallelization on CUDA platform. In the first part the basic principles on which the work is based are introduced. Subsequently, a detailed description of individual parts of the model and the issue of parallelization by graphics cards are presented. In the next part the creation of the required software and improving of the model properties of mentioned materials are described. That is followed by evaluation of the achieved results with the comparison of other modelling software. The conclusion summarizes the achievements and suggestions for the further development possibilities of the presented method of modelling.
|
|
| |
|
|
Methods of Static Buckling Analysis
Svoboda, Filip ; Eliáš, Jan (referee) ; Frantík, Petr (advisor)
The aim of this theses is to create application, which is able to calculate buckling load of structure made from 1D bar elements, using finite element method. introduction is devoted to basic principles of buckling and derivation of necessary formulas. Then are described all operations and numerical methods needed for the application. At the and is in detail analyzed few structures and results are compared with known solutions or with other applications.
|
|
|
Modeling of Elastic Mechanisms
Slaný, Jan ; Keršner, Zbyněk (referee) ; Frantík, Petr (advisor)
The thesis deals with constructing and solving a discrete mechanical model from the point of view of dynamics. As an example of a real-world problem which can be approximated in this way, the dynamical behaviour of a bow and arrow during loose have been chosen. In order to solve this particular type of model, a specialized piece of software has been developed. This method and software have been deployed to simulate shooting a straight bow of specific parametres. Two variants for the shape of the bowstaff have been evaluated.
|
|
|
Advanced evaluation of selected fracture tests of fibre reinforcement concrete specimens
Majda, Tomáš ; Frantík, Petr (referee) ; Keršner, Zbyněk (advisor)
The goal of this thesis was evaluation of extensive series of selected three point bending tests on fibre reinforced concrete specimens of ages 7, 28 and 126 days. First the measured data were adjusted by GTDiPS software. Than the assumed contribution of fibres in load--deflection diagram was approximated by regressive function. Contribution of matrix was calculated by deducting the approximated part from full diagram. Using StiCrack software the Young modulus, fracture toughness and fracture energy were calculated for both original and approximated diagram. All results were evaluated and tabled.
|
|
|
Modelling of postcritical states of slender structures
Mašek, Jan ; Eliáš, Jan (referee) ; Frantík, Petr (advisor)
The aim of the presented thesis is to create a compact publication which deals with properties, solution and examination of behavior of dynamical systems as models of mechanical structures. The opening portion of the theoretical part leads the reader through the subject of description of dynamical systems, offers solution methods and investigates solution stability. As the introduction proceeds, possible forms of structure loading, damping and response are presented. Following chapters discuss extensively the possible approaches to system behavior observation and identification of nonlinear and chaotic phenomena. The attention is also paid to displaying methods and color spaces as these are essential for the examination of complex and sensitive systems. The theoretical part of the thesis ends with an introduction to fractal geometry. As the theoretical background is laid down, the thesis proceeds with an application of the knowledge and shows the approach to numerical simulation and study of models of real structures. First, the reader is introduced to the single pendulum model, as the simplest model to exhibit chaotic behavior. The following double pendulum model shows the obstacles of observing systems with more state variables. The models of free rod and cantilever serve as examples of real structure models with many degrees of freedom. These models show even more that a definite or at least sufficiently relevant monitoring of behavior of such deterministic systems is a challenging task which requires sophisticated approach.
|
|
|
Modelling of damping devices in interaction with a structure
Kalina, Martin ; Lehký, David (referee) ; Frantík, Petr (advisor)
The aim of my master’s thesis was to create models of the damping device and observing their behavior in interaction with the structure. First was the construction separately modeled with Java application named FyDiK2D like a model with one degree of freedom. Model of construction takes form like a high, thin rod with full circular cross section. The lower part was restrained into the subsoil. The design was to verify the correct functionality of the model by comparing the analytical and numerical solutions. For capturing the precise behavior of the structure was converted to a multi-stage model. Then the pendulum damper was applied on this construction and found amplitude lies in highest point of multi-stage model. He was then replaced by tuned mass damper. By comparing these amplitudes from both dampers was found which kind of damper is efficient for multi-stage model.
|
|
|
Physical Discretization Modelling of Shrinkage
Bedáň, Jan ; Keršner, Zbyněk (referee) ; Frantík, Petr (advisor)
The aim of this thesis is design and programming of a numerical model of shrinkage of cement composites using physical discretization and solved by parallel processing. Introduction is about the shrinkage of cement composites and explanation of terms, which are included in this thesis. The main part deals with programming of the output model, the procedure of its creation and the results of simulations.
|
|
|
Steel Beam Structure Optimization
Lamoš, Radek ; Eliáš, Jan (referee) ; Frantík, Petr (advisor)
The main subject of this work is to find ideal solution of the steel frame structure and offer the best solution to investors. The aim is to get know how steel structures works, write down internal forces when parametres are changing. Parameters can be profiles, loads or many others. The output should be perfectly optimized construction. The content combines theory of structural mechanics and designing steel structures. This project could be very useful in practice designing of steel frame structures with the possibility of expansion by other parameters.
|
|
|
Modelling of Free Beam Loaded by Follower Load
Mašek, Jan ; Keršner, Zbyněk (referee) ; Frantík, Petr (advisor)
The aim of the presented thesis is to create a non-linear dynamical model of a free rod loaded by a follower force. The model is inspired by a slender flexible missile loaded by an end thrust. Because of the nature of the problem, the model has to be capable of large deflections. Another requirements on the model are to implement material the damping and the damping due to the interaction of the model with a surrounding medium and the influence of gravitational field. In the future, the model will be used for examination of the post-critical behavior of such construction. Therefore low computational demands of the simulation are required. The derived formulation of the numerical model will be implemented using the Java programming language. For observation of the simulation process and for monitoring of the state variables, an appropriate graphic interface will be created. The accuracy of the derived model will be verified by the comparison of selected values to the analytical solution.
|
guest ::
