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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Rám klece výtahu / Frame of the lift car

Mikšík, Libor January 2013 (has links)
This master’s thesis deals with the strength analysisby frame lift cage with lift capacity of 675 kg used the Finite Element Method (FEM). Furtheris performed the calculation of the guideanchoring instituted for this steel structure and the strength analysis of the used guides according to norm ČSN EN 81-1. The thesis also includes the drawing of the frame lift cage.
112

Zástavba pohonné jednotky LYCOMING do letounu Bristel UL / Installation of the LYCOMING power unit into the Bristel UL aircraft

Kročil, Petr January 2020 (has links)
This diploma thesis focuses on Lycoming drive unit mounting used in two-seater plane of VLA category (the very light aircraft). In the beginning characteristics of currently produced Bristell aircrafts are described. Following chapters aim at research selection of new drive unit mounting based on multi-criteria decision analysis. For selected unit, the weight, center of mass and flight performance are calculated. Additionally, the construction of engine mount is proposed. According to CS-VLA and CS-23 stress level of mounting is defined followed by strength verification. Later in this thesis, a suitable engine cover for engine and cockpit cooling is proposed. A complete fuel system is described in following chapter. Last chapter deals with financial costs of re-engining as well as aircraft operational costs.
113

Využití paralelizace při numerickém řešení úloh nelineární dynamiky / The exploitation of parallelization to numerical solutions regarding problems in nonlinear dynamics

Rek, Václav January 2018 (has links)
The main aim of this thesis is the exploration of the potential use of the parallelism of numerical computations in the field of nonlinear dynamics. In the last decade the dramatic onset of multicore and multi-processor systems in combination with the possibilities which now provide modern computer networks has risen. The complexity and size of the investigated models are constantly increasing due to the high computational complexity of computational tasks in dynamics and statics of structures, mainly because of the nonlinear character of the solved models. Any possibility to speed up such calculation procedures is more than desirable. This is a relatively new branch of science, therefore specific algorithms and parallel implementation are still in the stage of research and development which is attributed to the latest advances in computer hardware, which is growing rapidly. More questions are raised on how best to utilize the available computing power. The proposed parallel model is based on the explicit form of the finite element method, which naturaly provides the possibility of efficient parallelization. The possibilities of multicore processors, as well as parallel hybrid model combining both the possibilities of multicore processors, and the form of the parallelism on a computer network are investigated. The designed approaches are then examined in addressing of the numerical analysis regarding contact/impact phenomena of shell structures.
114

Volba parametru metody SUPG pro konečné prvky vyššího řádu přesnosti / Choice of the SUPG parameter for higher order finite elements

Kohutka, Jiří January 2014 (has links)
In this work, we deal with the finite element method Streamline Upwind/Petrov-Galerkin (SUPG) and use it to solve boundary value problem for the stationary convection-diffusion equation with dominant convection with Dirichlet boundary condition on the whole boundary of bounded polyhedral computational domain of dimension 1 and 2, respectively. We consider a quadratic Lagrangian finite elements on the line segments and triangles, respectively. The core of the work is a proposition of choice of stabilizing parameter of SUPG method as an elementwise affine function in outflow boundary layer and as an elementwise constant function in the rest of the computational domain. We show that this choice gives a more accurate solution than the choice of the stabilization parameter as a constant in each element. 1
115

Mechanická analýza vlivu výrobních odchylek na styk hlavice a jamky totální endoprotézy kyčelního kloubu / Mechanical Analysis of the Influence of Fabrication Tolerances on Contact Conditions between the Acetabular Cup and the Femoral Head in Total Hip Replacement

Koukal, Milan January 2010 (has links)
In endoprosthesis surgery there are typically a high percentage of implant defects, these can lead to failure of the whole prosthesis. One type of total hip replacement function loss is acetabular cup loosening from the pelvic bone. This disertation examines manufacture perturbations as one of the possible reasons for this kind of failure. Both dimension and geometry manufacturing perturbations of ceramic head and polyethylen cup were analyzed. We find that perturbations in the variables analysed here affect considered values of contact pressure and frictional moment. Furthermore, contact pressure and frictional moment are quantities affecting replacement success and durability. From obtained results it can be recommended to fit head and cup with a clearance of between 0 mm and 0.05 mm. It can not be recommend using interference type of fit because of strong deterioration of the contact conditions. Roundness perturbation of ceramic head should not exceed 0.025 mm.
116

Optimalizace parametrů úlohy s rázovým zatížením v programu LS-DYNA

ŠTANGL, Jiří January 2016 (has links)
Master's thesis focuses on numerical modeling of automotive tasks. The text is divided into two main parts. A fuel supply module is the main topic of all numeric analyses of this thesis and it is introduced in the first part. Basics of theoretical continuum mechanics and finite elements method are also explained in the first part. The second part is split into two main topics of the fuel supply module - material damping and contact numerical modeling. Practical reasons for parameter optimization are explained along with particular optimization results and underlying theoretical background.
117

Materiálově nelineární řešení prutových konstrukcí / Material nonlinear solution of beam structures

Kabeláč, Jaromír Unknown Date (has links)
The dissertation deals with solution of beam and frame structure considering material nonlinearity. The finite elements method (FEM) was used as calculation method. The objective of the dissertation was to develop and test finite beam element considering material nonlinearity. A detailed analysis of the problem provided a group of formulations of beam element. Part of the dissertation´s results has been, in several forms, implemented in commercial software. Beam element focused on solution of stress over solid cross sections is introduced in the theoretical part. In terms of topology it is a classical prismatic beam element with two nodes. Six degrees of freedom for translations and rotations are defined in each node plus 7-th degree of freedom for warping function from torsion. Load form axial force, bending moments, primary torsion, shear forces and eventually bimoment for secondary torsion were considered in cross section. Several variants of formulations were created according to inclusion of loading components into material nonlinearity and according to numeric integration method. Inclusion of geometric nonlinearity and fire resistance calculation are discussed in the dissertation. The above mentioned formulations were tested on prototypes as described in the application part which also provides information on the general procedure, architecture and technologies used for implementation of knowledge from the theoretical part into commercial FEM software. The dissertation shows implementation of plasticity for shell, solutions of cross section characteristics and stress on cross section, implementation of beam element with material nonlinearity and module for fire resistance of column. The above mentioned implementations of theoretical conclusions are the main outputs of the dissertation. These implementations are available in thousands of installations throughout Europe where being used at projection of significant constructions.
118

Výpočtová únosnost pilotových základů / Bearing capacity of pile foundations

Michalčák, Jan January 2018 (has links)
The thesis deals with calculation of foundation of pilot bases. In the first part, the author focuses on the numerical application of the Final Element Method for calculating the internal forces on the pilot and the software implementation of the proposal by the Masopust pilot (2nd Limit State). The second, practical part uses previous knowledge and created program to calculate the foundation of the bridge pillar on the bypass around Opava.
119

Výpočtové porovnání ojnic zážehových motorů / SI Engine Con-rods Computational Comparison

Vetešník, Pavel January 2008 (has links)
Diploma work is focused on computational comparison of con-rod of spark ignition four-cylinder engine with volume 1289 cubic centimeters and con-rod of spark ignition three-cylinder engine with volume 1198 cubic centimeters. 3-D models of inspected con-rods were based on real shape. Force loads effects were established after kinematic and dynamic analysis. Stress analysis was made for these force loads effects in selected cases with help of Finite element method. Two con-rods were compared by using of these results.
120

Vliv zanášení svazku trubek v kotli na jeho životnost / The effect of boiler tube bundle fouling on its service life

Volná, Kateřina January 2018 (has links)
Fouling of tube bundles in boilers on the flue gas side affects not only the service life, but also the boiler heat output and increases maintenance and operating costs. Therefore, it is necessary to minimize or completely eliminate this process. This thesis focuses on comparison of the service life and the heat output of the tube bundles with and without deposit in the coal fired boiler. Simulations of flue gas flow in area of tube bundles with and without deposit are performed using ANSYS Fluent software, which shows that the surface of tube bundles with deposit is much less heated than the surface without deposit. The thermal loads of tubes obtained by the CFD analysis are applied to the model, which is created in the program ANSYS Mechanical, where the calculation of the temperature field in the cross section of the pipe is realized. The effect of fouling on creep life and heat output is then evaluated based on simulation results. The results show that fouling increases creep life, but significantly reduces heat output of heavily fouled tubes. Hence the flue gas flows at a higher temperature to the rest of the tube bundle, and the service life of those tubes will therefore probably decrease.

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