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Lower limb prosthetics FEM analysis
Omasta, Milan ; Náhlík, Luboš (referee) ; Paloušek, David (advisor)
This masters´s thesis deals with computational modeling of transtibial lower-limb prosthesis. For assesment of loading character and geometrical configuration, the gait analysis of an amputee, including ground reaction force measurement, strain gauge analysis and motion analysis, was accomplished. Information on geometry was obtained using 3D optical scanning procedure. Material model was gathered using non-destructive mechanical testing and mimicked in a FEA software. For loading conditions the static structure analysys using FEM was accomplished. The critical poins in construction was found. Recognition of agreement about experimental and computational model was accomplished.
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Design and stress analysis of temperature and force sensor in hot rolling process.
Nejedlý, Pavel ; Pohanka, Michal (referee) ; Horský, Jaroslav (advisor)
In the process of hot rolling is roll surface thermo-mechanically stressed. To define lifetime of roll or to increase it by change of thermal mode, temperatures and forces acting on this roll need to be known. For this purpose should be used sensors, that are placed near by surface of roll. Aim of the first part of diploma thesis is to debug 2D computing model (MKP) to achieve the match of temperature graphs with experimentally measured values, which was recorded by temperature sensors in real process of rolling. In the second part the same temperature boundary conditions are applied on 3D model, which is used to solve mechanical strength check of the temperature sensor. The last part of thesis is design and verification of mechanical strength of the designed force sensor. The used boundary conditions were acquired in Laboratory of heat transfer and flow. The computing system ANSYS 11 is used to design a model of geometry and numerical calculation. This diploma thesis will be used as donating solution for the granted project, which started in this year with Laboratory of heat transfer and flow partnership.
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Computational and experimental analysis the state of stress of turbine blade
Damborský, Petr ; Jaroslav, Kovařík (referee) ; Malenovský, Eduard (advisor)
This diploma thesis deals with dynamic analysis of the steam turbine blade. This blade is part of the last row of low pressure level of steam turbine. Computational analysis has been performed in first part using FEM and software ANSYS. A Transient analysis has been used to solve forced vibrations. Main goal is to obtain a behavior of main stresses and its directions as a function of loading of the blade in the crack initiation area. Second part deals contain a an experiment. Experiment has been set up to perform a modal analysis which is necessary to obtain a fundamental numbers. Then the vibration of the blade has been performed. To perform this experiment same edge conditions as which has been used during the computational analysis. Goal is the same as in the first part – obtain a behavior of main stresses and its directions as a function of loading of the blade in the crack initiation area. The comparison of results obtained during experimental analysis and computational analysis has been performed in the last part of the thesis. Also the question if any geometrical nonlinearities appeared during analyses is answered.
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Motivation of employees as a factor of competitiveness of the company in the international business
Rýznarová, Pavla ; Němečková, Iveta (advisor) ; Machková, Hana (referee)
There exists a never-ending struggle to gain a dominant market position at the national and international markets. The globalization and processes of integration have made this struggle more intense. It is more and more difficult to find new means to achieve desired goals. The best means of companies are represented by their competitive advantages and it does not matter if they focused on the price, product's attributes or on the quality of the delivery. However, we can consider as the most successful companies those that will be able to use their competitive advantages synergistically and those that will be able to create more inimitable sources of the competitive advantages. Motivation of employees is one of these sources. People are endowed with knowledge and skills. People represent the driving force of today's economic potential. Let's satisfy their needs and observe the growth of their own initiative and productivity.
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Departures Hall
Kubíček, Ján ; Buchta, Stanislav (referee) ; Bajer, Miroslav (advisor)
This thesis focuses on the design and assessment of the supporting steel structure of departures hall for international airport Pardubice. The design is processed in two variants, one of which is selected and further elaborated. The hall contains one-story built for office and comercial use. To obtain the internal forces in the structure, modelling of the hall in the FEM computermodeling software was selected. The thesis includes manual assessment of selected elements and details, the assessment of elements in computational software, drawings and bill of material.
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Security of wireless computer networks IEEE 802.11
Škodák, Jaroslav ; Jeřábek, Jan (referee) ; Koutný, Martin (advisor)
This work describes available and used standards, protocols and mechanisms used to secure IEEE 802.11 wireless networks. In the next section are listed vulnerabilities and possible attacks against different types of security. The principles of individual attacks on authentication, WEP security and WPA/WPA2 personal mode are described and realized using various software especially linux program aircrack-ng. Password for WEP security is obtained by passive eavesdropping data, using ARP replay injection and by creating own frames. The last two methods are used to generate traffic on the network, which is captured and then used to derive the WEP password. By injecting ARP frames, password was found in the number 60 000 captured frames and about 180 000 frames of data was needed for passive method. Decryption of WEP frame was done by fragment and KoreK chopchop attacks. This decrypted frame could be used to create fake frames and obtain WEP password. Brute force attack is realized for security WPA (WPA2) personal mode (often due to lack of strong password) by comparing password (passphrase) from password list. Speed of comparing is about 200 passwords/s.
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CFD model of modulated water jet
Foldyna, Josef ; Sitek, Libor
In this paper, results of CFD simulation of modulated jet break-up in the air are presented. The results are compared with results of visualization of modulated jets obtained in the laboratory experiments. In addition to that, results of simulation of modulated jet impact onto flat perpendicular surface are compared with laboratory measurement of stagnation force of modulated jet.
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Education regarding issues related to traffic accident insurance fraud
VIČAR, Jan
Based on their own experience the insurance companies are forced to intensively deal with detection and prevention of insurance frauds. Education of the public is the most effective way how to prevent the amount of insurance fraud cases, so therefore the main goal of this thesis is to provide to police officers in the Czech Republic as well as to other people the education material focused on occurrence of insurance frauds happening in connection with traffic accidents. The thesis is also the warning against committing the offense of insurance fraud, because the relevance and also possible consequences of offense are here also mentioned. Is shows how big effort is given by insurance companies and the Police of the Czech Republic for detection and prevention with the usage of modern methods. Practical part of the thesis contains knowledge and experience of insurance assessor and criminologist of the Police of the Czech Republic, gained by the personal interview. These experience from real work and situations are the most valuable resources.
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Stiffness estimation at the machining head and the strength analysis of the moving parts of the machining center MCV 1220.
Zbožínek, Martin ; Houfek, Martin (referee) ; Vrbka, Jan (advisor)
Main objective of the work was to estimate the possibilities and the limits of elementary stress and strain analysis of the construction. At the beginning it was necessary to simplify the problem to the 1-D bar problem. The calculation was performed for three typical loading cases, namely for the middle and the border position of the machining head. The contact forces and momentums and the displacements at the machining head have been calculated. The obtained results were then used for the stiffness evaluation of the construction at the machining head. The strength analysis of the moving parts of the machinig center has been done, too. Modern software products (Autodesk Inventor, ProENGINEER, ANSYS Workbench, Maple, Mathcad, etc.) were used for the calculation. The results were compared with The Finite Element Method results.
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Strain, stress and strength analysis of the frame construction.
Hrubý, Jaroslav ; Vlk, Miloš (referee) ; Vrbka, Jan (advisor)
This work deals with the stress and strain calculation as well as with the safety evaluation at the plane (2-D) frame loaded by the individual force F. The aim of this work is not acquiring the use of cutting-edge computer programs to determine the stress and deformation, but to learn how to use practically the basic calculation methods being taught at the subject Strength of materials to get practical experience with the application of these calculation methods.
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