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Design of computational algorithm for using of hollowed shaft in electric machine
Tobiáš, Jan ; Hadaš, Zdeněk (referee) ; Vlach, Radek (advisor)
The aim of this work is to develop the possibility of usage the hollow shafts in electric machines. The first part focus on explanation theory of mechanic, which is connected with loading of the shaft. Specifically are explained the methods of computation deformation and normal stress. Next is mentioned the theory of gyroscope and described its consequence. After that is explained problematique of critical speeds. In the following part is described process of solving the shaft loading according the previous analytic formulas. These formulas are formulated to be able to reflect the shaft loading depending on value of inner diameter as property. Practical part focus on creating the calculator for usage the hollow shaft in electric machines. In this chapter is described how the calculator works and how to controll it by user. In the last part are shown calculated results and their analysis. In the summary is mentioned possible usage of the results and ideas for improvements.
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Web Application with Interactive Educational Video
Tobiáš, Jiří ; Burget, Radek (referee) ; Kolář, Dušan (advisor)
Goal of this work is create web application for the management of interactive education contents. The application will be able to show interactive content for users in course. Also, it will show users the result of their activities. For content administrators, the application will provide more detailed outputs that should serve as feedback, to improve the content. For creating outputs, the application will need to be able record users activities.
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Analysis of transfer matrix method using for calculation of electrical machines rotor with influence of magnetic pull
Tobiáš, Jan ; Majer, Zdeněk (referee) ; Vlach, Radek (advisor)
This master thesis is dealing with modeling of the rotor system based on the numerical transfer matrix calculations. This method is suitable for fast analysis of beam bodies to observe the resulting deflection and critical speed in regard to the initial circumstances. The bearing stiffness is a significant input factor that affects the outcomes of the analysis, especially the critical speed the rotor system. First of all,the available approaches to analyze the bended beam bodies are discussed focused on explanation of the transfer matrix algorithm. After that, the approach to estimate the bearing stiffness based on the Hertz contact theory is presented. Further, a brief explanation is given about the heat arising in the rotor bearings. The following chapters are focused on description of the software solver for rotor system analysis based on the transfer matrix method, considering the bearing stiffness estimation based on Hertz contact theory, with possible calculations of the induced bearing heat losses. In the end, the practical use of the developed software is presented with the analysis of the obtained results of the rotor deflection, critical speed, and bearing power loss. There is also discussed a comparison of the different bearing stiffness estimation with the impact to the computation outcomes, especially on the rotor critical speed, followed by comparison conclusion implementation into rotor system analysis.
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Analysis of transfer matrix method using for calculation of electrical machines rotor with influence of magnetic pull
Tobiáš, Jan ; Majer, Zdeněk (referee) ; Vlach, Radek (advisor)
This master thesis is dealing with modeling of the rotor system based on the numerical transfer matrix calculations. This method is suitable for fast analysis of beam bodies to observe the resulting deflection and critical speed in regard to the initial circumstances. The bearing stiffness is a significant input factor that affects the outcomes of the analysis, especially the critical speed the rotor system. First of all,the available approaches to analyze the bended beam bodies are discussed focused on explanation of the transfer matrix algorithm. After that, the approach to estimate the bearing stiffness based on the Hertz contact theory is presented. Further, a brief explanation is given about the heat arising in the rotor bearings. The following chapters are focused on description of the software solver for rotor system analysis based on the transfer matrix method, considering the bearing stiffness estimation based on Hertz contact theory, with possible calculations of the induced bearing heat losses. In the end, the practical use of the developed software is presented with the analysis of the obtained results of the rotor deflection, critical speed, and bearing power loss. There is also discussed a comparison of the different bearing stiffness estimation with the impact to the computation outcomes, especially on the rotor critical speed, followed by comparison conclusion implementation into rotor system analysis.
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Design of computational algorithm for using of hollowed shaft in electric machine
Tobiáš, Jan ; Hadaš, Zdeněk (referee) ; Vlach, Radek (advisor)
The aim of this work is to develop the possibility of usage the hollow shafts in electric machines. The first part focus on explanation theory of mechanic, which is connected with loading of the shaft. Specifically are explained the methods of computation deformation and normal stress. Next is mentioned the theory of gyroscope and described its consequence. After that is explained problematique of critical speeds. In the following part is described process of solving the shaft loading according the previous analytic formulas. These formulas are formulated to be able to reflect the shaft loading depending on value of inner diameter as property. Practical part focus on creating the calculator for usage the hollow shaft in electric machines. In this chapter is described how the calculator works and how to controll it by user. In the last part are shown calculated results and their analysis. In the summary is mentioned possible usage of the results and ideas for improvements.
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Compulsory Contractual Insurance
Tobiáš, Jan ; Vybíral, Roman (advisor) ; Karfíková, Marie (referee)
Compulsory Contractual Insurance Abstract The subject of this diploma thesis is legal regulation of compulsory contractual insurance in the Czech legislation with a focus on its general regulation in civil law. The special regulation of compulsory liability insurance for lawyers, health service providers and the insurance of a guarantee in case of bankruptcy of the travel agency is also called for. The methods of description, analysis and, to a lesser extent, comparisons are used to fulfil the objectives of this work. The first chapter deals with the concept of compulsory contractual insurance. It includes a historical excursion. The largest part of the chapter describes the types of compulsory insurance and their distinction from voluntary and statutory insurance. The conclusion of this section is a preview of the legislation on compulsory contractual insurance in selected countries. The second chapter focuses on the description and analysis of the current legislation on compulsory insurance. At the beginning of the chapter, a description of the general regulation of the insurance contract, its subjects and form are made. The largest part of the chapter is devoted to the analysis of provisions that represent the general basis for compulsory contractual insurance. Introduced are partial changes made by the...
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Web Application with Interactive Educational Video
Tobiáš, Jiří ; Burget, Radek (referee) ; Kolář, Dušan (advisor)
Goal of this work is create web application for the management of interactive education contents. The application will be able to show interactive content for users in course. Also, it will show users the result of their activities. For content administrators, the application will provide more detailed outputs that should serve as feedback, to improve the content. For creating outputs, the application will need to be able record users activities.
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Analysis of cyclic plasticity of fatigued nickel based superalloys at elevated temperatures
Petrenec, Martin ; Tobiáš, Jiří ; Polák, Jaroslav ; Šmíd, Miroslav ; Chlupová, Alice ; Petráš, Roman
Cyclic strain controlled multiple step tests have been performed on cylindrical specimens of cast Inconel 738LC superalloy at 23 and 800 °C and Inconel 792-5A superalloy at 800 °C in laboratory atmosphere. The effect of temperature on the cyclic stress-strain response characterized by internal and effective cyclic stress components and on the dislocation arrangement has been studied. The evolution of the effective and internal stress components and effective elastic moduli were derived from the hysteresis loops analyzed according to the statistical theory of the hysteresis loop. Cyclic hardening/softening curves and shortened cyclic stress-strain curves were obtained at all temperatures in both superalloys. The shortened cyclic stress-strain curves (CSSCs) can be fitted by power law at all temperatures and for both materials. They are shifted to lower stresses with increasing temperature. The CSSC of Inconel 792-5A is shifted to higher stress amplitude in comparison with that of Inconel 738LC due to different number and type of precipitates. Observation of dislocation structures by TEM revealed cyclic strain localization into persistent slip bands. Cyclic stress-strain response is compared at all temperatures in both superalloys and discussed in relation to the changes of internal and effective stress components and microstructural parameters of the material. Higher stress response of the Inconel 792-5A than of the Inconel 738LC superalloy at 800°C is due to higher effective stresses of respective γ´ phases.
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Low Cycle Fatigue and Analysis of the Cyclic Stress-strain Response in Superalloy Inconel 738LC
Tobiáš, Jiří ; Chlupová, Alice ; Petrenec, Martin ; Polák, Jaroslav
The paper describes the results of fatigue behavior study on cast polycrystalline nickel based superalloy tested at 23 and 800 °C. Cylindrical specimens of Inconel 738LC were cyclically strained under total strain control to fracture and multiple step tests were performed to study the effect of temperature on the internal and effective cyclic stress components. Fatigue life curves were approximated by the Manson- Coffin and Basquin laws. The resulting curves were shifted to lower fatigue lives with increasing temperature. The evolution of the effective and internal stress components and effective elastic modules were derived from the hysteresis loops which were analyzed according to the statistical theory of hysteresis loop. Cyclic stress-strain response at both temperatures and the changes of internal and effective stress components were discussed in relation to microstructural parameters of the superalloy.
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