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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.
11

Most přes železniční trať / Bridge ower railway line

Prekop, Michal January 2020 (has links)
Diploma thesis is focused on a design of the road bridge of the category S7,5 in cadastral territory of a municipality Polanka nad Odrou. Three preliminary studies have been proposed. Box girder beam with a slant walls were selected for more detailed processing. Construction of the bridge is going to be build by time-dependent analysis on a solid formwork. The calculation of load is done by using computer software Midas Civil 19 v 2.1. and Scia Engineer 19.1. Selected preliminary was assessed according to the recent Europan standards.
12

Rám kočky 330 t mostového licího jeřábu / Frame of foundry trolley crane 330 t

Otevřel, Marek January 2015 (has links)
The topic of this diploma thesis is the frame of the foundry trolley crane 330/65/20t. The crane crab is used for handling with molten metal. The frame is analyzed by strength inspection and fatigue strength inspection. The process is according to ČSN EN 13001. The analyses are made by using finite element method on a beam and shell models. The diploma thesis was made in cooperation with the Královopolská a.s. company.
13

Improved equivalent circuit modeling and simulation of magnetostrictive tuning fork gyro sensors

Starke, E., Marschner, U., Flatau, A. B., Yoo, J.-H. 06 September 2019 (has links)
In this paper a new equivalent circuit is presented which describes the dynamics of a prototype micro-gyro sensor. The concept takes advantage of the principles employed in vibratory gyro sensors and the ductile attributes of GalFeNOL to target high sensitivity and shock tolerance. The sensor is designed as a tuning fork structure. A GalFeNOL patch attached to the y-z surface of the drive prong causes both prongs to bending the x-z plane (about the y axis) and a patch attached to the x-z surface of the sensing prong detects Coriolis-force induced bending in the y-z plane (about the x axis). A permanent magnet is bonded on top of each prong to give bias magnetic fields. A solenoid coil surrounding the drive prong is used to produce bending in the x-z plane of both prongs. The sensing prong is surrounded by a solenoid coil with N turns in which a voltage proportional to the time rate of change of magnetic flux is induced. The equivalent circuit enables the efficient modeling of a gyro sensor and an electromechanical behavioral simulation using the circuit simulator SPICE. The prongs are modeled as wave guiding bending beams which are coupled to the electromagnetic solenoid coil transducer. In contrast to known network approaches, the proposed equivalent circuit is the first tuning fork model, which takes full account of the fictitious force in a constant rotating frame of reference. The Coriolis force as well as the centrifugal force on a concentrated mass are considered.
14

Hydro-mechanical optimization of a wave energy converter

Ekweoba, Chisom Miriam January 2022 (has links)
Wave energy conversion technology has gained popularity due to its potential to be-come one of the most preferred energy sources. Its high energy density and low car-bon footprint have inspired the development of many wave energy converter (WEC) technologies, few of which have made their way to commercialisation, and many are progressing. The Floating Power Plant (FPP) device is a combined floating wind and wave converter. The company, Floating Power Plant, was established in 2004 and has developed and patented a floating device that consists of a semi-submersible that serves as a foundation for a single wind turbine and hosts four wave energy converters (WECs). Each WEC consists of a partially submerged wave absorber whose pitching motion generates energy from incoming waves. The wave absorbers are connected to an oil hydraulic power take-off system located in a dry “engine room” above the free water surface, where the mechanical energy in the absorber is converted to electricity. When undergoing pitching movements, there are interactions between individual wave absorbers and the surrounding platform. This thesis focuses on developing methods to improve the FPP WEC’s hydrodynamic interactions. The first part of this thesis optimises the wave absorber (WA) ballast. An ana-lytical model is developed to enable systematic selection of WA ballast combination with significantly less computational effort when compared with the more conven-tional means, such as using CAD software. The study suggests an algorithm with which the absorbed power and resonance frequency can be improved and adjusted by manipulating the ballasts’ mass, the position of its centre of gravity, placement and inclination of the WA. The proposed method is generic and can be applied to other WEC concepts or submerged bodies in general. The results show the feasibility of designing the absorber ballast to offer passive control for increased wave absorption. It demonstrates the effect of ballast on the WA inclination, resonance frequency and response amplitude operator (RAO). The second part focuses on the optimisation of the FPP platform geometry. The genetic algorithm optimisation technique is implemented to maximise the annual en-ergy produced by the relative pitch motion of the WA to the floating platform. The optimised variables are characteristic lengths of the floating platform, most of which are part of the immediate surrounding walls of the absorber. The objective function is a function of the WA’s annual energy production (AEP) and RAO. Results show the feasibility of improving the hydrodynamic interaction between the floating platform and its integrated wave absorbers for a given wave climate by using a heuristic search technique. The number of iterations to convergence tends towards increased values when considering more optimised variables. It is also observed that the computational time appears to be independent of the number of variables but is significantly impacted by the computational power of the machine used.
15

Obloukový silniční most / Highway arch bridge

Vavřička, Lukáš January 2022 (has links)
The aim of the master thesis was a design of arch highway bridge made of prestressed reinforced concrete. In the beginning two versions of construction were designed, with box-girder and double-girder cross section of bridge deck, from which the variant of double-girder cross section in combination with box-girder arch were chosen for further detail postprocessing. The basics of the solution laid in right choice of dimensions of elements creating load-bearing system and construction geometry. Subsequently global beam model was created, which was used to prestress design and structural assessment of ultimate and serviceability limit states of pillars, arches and bridge deck during the building phases, service lifetime and in the end of lifetime of construction. For detail assessment, linear and nonlinear analysis was created using Midas Civil. To check the cross-sectional direction of bridge deck, slab model was made using Scia Engineer software
16

Návrh předpjatého komorového mostu / Design of prestressed box gireder bridge

Hofírek, Radovan January 2013 (has links)
This thesis deals with bridging of a lowland valley and the creek Dolanský in the section Jánovce – Jablonov on the Slovak motorway D1. Four variants of the bridge have been developed. Subsequently prestressed single box gilder with large overhangs that are supported by precast struts was selected as the most suitable variant. The construction of the bridge will take place in a formwork suspended on overhead launching scaffolding. The static assessment according to the Europan standard has been drawn up for this variant. The load of the bridge is projected according to the ČSN EN 1991-2 - Traffic loads on bridges and the dimensoin of concrete structures according to the ČSN EN 1992-2 - Concrete bridges - Design and detailing rules. The calculation of load is done using computer software SCIA Engineer 10.1 and Midas Civil.
17

Dynamická analýza koleje / Dynamic analysis of track

Mojžíšek, Dominik January 2018 (has links)
The diploma thesis deals with descriptions of vehicle - track dynamic interface. There are described basic analytical models of railway track. The numerical models are created by using finite element methods with moving load simulated axle of rail vehicle. The aim of thesis is to create the model which most accurately describes the dynamic phenomena in the track. The results from models are compared with data obtained by measuring in the track. Next aim of thesis is to determine dependency of rail cross-sectional characteristics on equivalent rail head wear and then on rail deflection.

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