|
|
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.
|
|
|
Analysis of welded joints using Finite Element Method
Štěrba, Martin ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
This diploma thesis is concerned with the numerical analysis of welded aluminim structures. In these structures, there are significant decreases in the mechanical properties at the area of the weld and in the heat affected zone as a result of welding. Within this thesis, simulations of quasi-statically loaded welded joints made from EN AW-6082 T6 alloy were performed to investigate the load capacity and ductility of these joints. Computations were performed using a programme system based on an explicit finite element method. To describe material anisotrophy, a nonlinear material model called the Weak texture model was chosen. Material properties of the weld and the heat affected zone were considered to be different from base material. The required material parameters were adopted from available literature, however, material tests and indetification procedure of these parameters were described. In comparison with the experimental data, the results of the numerical simulations showed a relatively good ability of models to capture load capacity of studied welded joints. Nevertheless, due to mesh sensitivity of models caused by localization of deformation, it was not possible to determine ductility of these joints.
|
|
|
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.
|
|
|
Verification of nonlinear material models
Holada, Jiří ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The thesis deals with the verification of nonlinear materials during a dynamic test. The reinforced concrete beam is subjected to an impact load. The deterministic finite element model will be developed using several nonlinear material models. The last part describes the sensitivity analysis with MOP (Metamodel Optimal Prognosis).
|
|
| |
|
|
Analysis of the wind effect on the construction
Tačner, Jan ; Hradil, Petr (referee) ; Kala, Jiří (advisor)
Diploma thesis deals with static and dynamic analyses of a slender bridge structure behavior. The footbridge structure model was created in ANSYS 14.5 programing system. Static and a modal analyses were made afterwards and according to these analyses dynamic wind load and dynamic pedestrian load were applied. Wind load was applied as option of deck without a handrail and as option of deck with fully airtight handrail. Pedestrians were perceived as group of pedestrians and as a sparse crowd. Both applied loads were solved by harmonic analyses. Results of these analyses are resonance curves and tables of accleration.
|
|
|
Ultimita
Jindra, Daniel ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
Structural beam and shell models were assembled in ANSYS program package. Design loads are defined according to Euro codes. Nonlinear analysis of structure has been established. Ultimate limit state of beams and cross sections were determined. Obtained results of ultimate limit state analysis were compared with Euro codes for design thin-walled steel structures.
|
|
|
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.
|
|
|
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.
|
|
|
Wind loads of building structures
Štěrba, Martin ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The bachelor thesis deals with the analysis of the effects of wind load on building structures. In the context of the work is solved the numerical modeling of flow around the solid cylindrical bodies at high Reynolds numbers. To the simulations has been used computational software ANSYS CFX. The outputs of the work are the values of Strouhal numbers and the values of drag and lift coefficient depending on the Reynolds number.
|
guest ::
RSS feed.