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Comparison of approaches to the assessment of buckling of variously long and supported columns
Ostratická, Klára ; Pokorný, Jan (referee) ; Šebek, František (advisor)
The bachelor's thesis deals with assessment of the buckling stability. The differences between elastic and inelastic buckling and effects on the critical force are described. The effect of material, supports and length of the column is described in more detail. During buckling, the character of deformation changes, the compressed column starts to bend at a definite point. This point is called bifurcation point and the limit is amount of critical force. The calculation of critical buckling force is carried out analytically for selected examples using the Euler and Johnson methods. The results are numerically checked by the finite element method in Ansys. The results for linear buckling are identical. Examples of nonlinear buckling are also calculated numerically. The difference is found in critical force for contact surfaces without friction and with friction. Defining the critical force can prevent the collapse of the entire structure, thus avoiding catastrophic incidents.
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Stress analysis of the only extant pier of the former Ivančice viaduct
Pelaj, Jakub ; Fuis, Vladimír (referee) ; Vaverka, Jiří (advisor)
The bachelor thesis focuses on the stress analysis of the original Ivančice viadukt pillar. The introductory part describes the theoretical basis necessary for the analysis. The second part deals with the history and assembly of the bridge. The third part dedicates to the creation of three-dimensional structure which serves as a basis for conducting the stress analysis. The following part provides a detailed expanation of the solution process and analytical calculations itself. In the conclusion, the obtained results are verified using numerical calculations a supplement with partial results concerning an additional type of load.
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Buckling analysis of the load-bearing system
Majer, Tomáš ; Löffelmann, František (referee) ; Šplíchal, Jan (advisor)
The research part of the work summarizes the knowledge in the field of calculation of buckling stability and methods of heat transfer. The next part deals with the calculation of the buckling stability of two types of samples using an analytical approach, finite element method, and verified using experimental measurements. Finally, the work deals with CFD calculation for determining the temperature field on the examined samples, which is used to calculate the buckling stability with temperature influence.
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Stability analysis of swinging props turbines
Bukovský, Petr ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
Master thesis deals with a computing simulation of two props turbines lines. The thesis output is gaining maximum possible load, at which a commencement of deformation stability critical state for various geometrical imperfections has not arisen yet. The calculation has been done by FEM in two different ways: linear solution (using a calculation conversion into eigenbuckling) and nonlinear solution (using a FEM deformation option). Result analysis compares both methods outcomes. Safety factor for the props operation has been proposed taking into consideration known influences on operating state.
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Finding kinematic quantities of a mechanism and a structural analysis of its members after blockage
Zvozil, Ondrej ; Vosynek, Petr (referee) ; Fuis, Vladimír (advisor)
Diplomová práca, ktorá vznikla v spolupráci so spoločnosťou AUFEER DESIGN (AFD), sa zaoberá analýzou konkrétneho stieračového mechanizmu automobilu. Najprv je uvedená stručná história stieračov. Stieracie sústavy sú potom rozdelené podľa ich usporiadania a spôsobu pohonu. V nasledujúcej kapitole je formulovaná problémová situácia, problém a systém podstatných veličín. Kinematické veličiny kľúčových bodov mechanizmu sú určené analytickým aj numerickým prístupom. Výpočtový model pre kinematickú analýzu je vyvinutý v Matlabe a SimMechanics. Ďalšia časť je venovaná vytváraniu konečno-prvkového modelu v programe ANSA. Všetky deformačne-napäťové analýzy sú vykonané v programe Abaqus. Prvá z nich je parametrická štúdia, ktorá odhaľuje kritické polohy mechanizmu z hľadiska tlakového namáhania určitých súčastí. Mechanizmus v kritických polohách je potom zaťažovaný so zablokovanými ramenami stieračov. Nakoniec sú urobené lineárne analýzy straty vzpernej stability súčastí, u ktorých môže nastať, nasledované nelineárnymi analýzami so zahrnutými imperfekciami.
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Evaluation of buckling risk at beams made of two various materials
Zvěřina, Martin ; Dušek, Daniel (referee) ; Burša, Jiří (advisor)
Aim of this work is evaluation of buckling risk at beams made of two various materials and delimitation limits for critical power buckling beam from two various materials by the help of relations for prismatic beam. Further is here processed analyst determination critical force buckling for free beam from two various materials and also analyst determination critical force buckling for fixed beam from two various materials.
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Analysis of possibilities of solution of buckling of a screw-shaped beam
Pokorný, Jan ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
Bachelor’s thesis deals with the effect of the pretwist of a column on the increase in buckling load and also focuses on a column with rectangular cross section. This problem is divided into two main parts. The first one is represented by the column with a large thread pitch, the second one by a small thread pitch. The results are obtained by a numerical approach using MATLAB software. The verification is carried out via finite element software. The outcome of this thesis is plotting the ratio of the critical loads of the twisted and prismatic columns against the ratio of the side lengths of the rectangular cross section. The results are shown for both types of considered columns.
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Evaluation of risk of buckling in bimaterial columns
Benešovský, Marek ; Návrat, Tomáš (referee) ; Burša, Jiří (advisor)
Bachelor’s thesis contains the principle of determining the critical load of buckling of column with nonconstant parameters. There is a solution for the column composed of one and two materials and solutions for the column with two different cross-sections. An essential part of this work is the numerical solution, which is used for solving nonlinear equations in implicit form. In this work, these equations occur when solving columns of two materials and two different cross-sections. For the numerical solution, it is necessary to set an initial approximation. Initial aproximation and numerical solution are solved by a program, which was created for this work. In the final part, are stated several graphs. The most important graph represents relation of the ratio of approximate critical load obtained by interpolation of Euler's relation and critical load gained numerically on the ratio of Young’s modules of both materials.
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Calculation of workpiece deflection when machining
Grebeň, Petr ; Zouhar, Jan (referee) ; Píška, Miroslav (advisor)
Selected chapters of the science branch "Elasticity and strength" applied to manufacturing of thin parts with various solution approaches. Applying theory of bars and a non-linear differential equation for the deflection line of the second order to a machined shaft. Numerical calculation in the ANSYS program. Evaluation and design of solution variants to machine thin shaft parts without supporting them.
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