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Application of drawingless documentation in the design of a milling clamping device
Schneider, David ; Michalec, Michal (referee) ; Svoboda, Petr (advisor)
The bachelor's Thesis describes the construction of a milling fixture for clamping a component on a machine tool using drawing-less documentation. Available methods of clamping workpieces for machining are described here, and the creation of drawing-less documentation is further explained. Today, in the vast majority of cases, classic drawing documentation is used, which is in many ways more tedious than the processing of described 3D digital data about the model. The work describes the creation of drawing-less documentation on a specific design solution of a milling clamping device. This solution is developed on the basis of three proposals for possible conceptual solutions for the clamping fixture. Complete, drawingless documentation of all individual parts of the product. The bachelor's thesis shows the advantages of drawing-less documentation compared to 2D drawings of components, but also mentions shortcomings that reduce the overall impression. A possible improvement that could simplify the presentation of digital model data is suggested.
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Optimization of hydrostatic bearing pad geometry using CFD simulation
Dryml, Tomáš ; Vimmr, Jan (referee) ; Michalec, Michal (advisor)
The master's thesis deals with the optimization of hydrostatic bearing pad geometry using CFD simulation and experimental measurements. By combining experimental and numerical approaches, the effect of variation of hydrostatic bearing recess shape and depth on individual operating parameters is investigated. The effect of geometry variations is determined by numerical simulations which have been validated with experimentally obtained data. The results show that the ideal recess depth should correspond to 20-50 times the lubrication layer height The simulations also show that depth variation has a significant effect on the operating parameters. In contrast, the variation of the recess shape does not significantly affect the operating parameters of the bearing. The design of the optimum geometry of the hydrostatic bearing is particularly important because it can bring significant financial and energy savings associated with the operation of (especially large-sized) hydrostatic bearings.
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Hydrostatic bearings for wind energetics
Procházka, Michal ; Foltýn, Jan (referee) ; Michalec, Michal (advisor)
This bachelor thesis deals with the bearing of the main rotor shaft of a wind turbine using hydrostatic bearings. Wind turbines come in many designs and the thesis then determine the operating parameters and bearings used in horizontal axis turbines of different installed power outputs. Currently, repairs, as well as servicing of bearings, are very costly and affect the operation of the entire power plant. Hydrostatic bearings offer advantages that could reduce the failure rate of wind turbine bearings. The operating parameters of turbines of different outputs were used to calculate the selected hydrostatic bearings. The results shows that the use of this type of bearings is possible for turbines with different power outputs, but higher efficiency is estimated for larger turbines (for example 8 MW turbine). The energy consumption of bearing, required to drive the hydrostatic bearings, reaches 0,03 % of the total output, compared to 0,39 % for the smaller 55 kW turbine. The calculation has been simplified in the initial energy performance estimation and further steps could include bearing geometry optimization or extending the operating parameter range of the wind turbines.
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Influence of inlet hole position in hydrostatic bearing recess using CFD simulation
Androvič, Dominik ; Svoboda, Petr (referee) ; Michalec, Michal (advisor)
This bachelor thesis deals with the influence of inlet hole position in hydrostatic bearing recess in combination with lubricating film tilting using CFD simulation in ANSYS Fluent software. Before the investigation, encapsulation of hydrostatic bearing, CFD simulation and research of hydrostatic bearings was implemented. For investigation of ours the analytical reference model of an axial hydrostatic bearing based on recommended design parameters was created. The main parameters of interest maximal recess pressure and load capacity of bearing were emerged from analytic solution. Subsequently, the maximal recess pressure and load capacity of the bearing were computed using CFD simulation for selected position of the inlet hole and the lubricating film tilt. The results indicate that the load capacity of the bearing is decreasing with the increasing lubricating film tilt. However, in case of alteration of inlet hole position even combined with selected lubricating film tilts no significant changes in maximal recess pressure or load capacity of the bearing with changing in position of inlet hole has been observed. The obtained results might be used to improve the design of hydrostatic bearings.
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Design of the anti-vibration platform for laboratory scale
Michalica, Jakub ; Michalec, Michal (referee) ; Košťál, David (advisor)
The bachelor thesis deals with the design of passive antivibration platform for laboratory weighing machine. In the first part of the work are listed some common isolation solution. Next is design of three possible solution concepts of this platform and their description. The calculations for possible isolators, analysis of deficiencies of the design and their solutions and measurements of the final antivibration characteristics of the finished piece are made. In the end the platform is compared if it satisfies required parameters.
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Design of a test rig for stress visualisation using photoelasticimetry
Doležel, Miroslav ; Rebenda, David (referee) ; Michalec, Michal (advisor)
The purpose of this work is to construct a specific loading device for the observation of moving samples in the existing polariscope. The experimental method of photoelasticity is often used to observe stationary samples, but the observation of moving samples is less common. However, the time-varying development of the stress profile is very important for understanding of the stress cycles in the machine components. The theoretical part contains a basic information about the method of photoelasticity, its advantages and limitations and the possibility of its use. Then the dynamically stressed machine elements are mentioned, from which the gear is selected as a preferable element for observation in the polariscope. Furthermore, attention is focused on materials and techniques of sample production. The determination of the required load of the gear sample is based on these findings. The most suitable design of the loading device capable of inducing specified stress in the samples is proposed and the critical nodes of the structure are supported by the strength calculations. This design offers variability for clamping different sample sizes and can thus be used to investigate stress in other gear configurations as well.
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Race car bonnet shape design based on flow analysis
Šnajdr, Petr ; Kvarda, Daniel (referee) ; Michalec, Michal (advisor)
The bachelor’s thesis deals with reducing aerodynamic drag of a pneumobile. The thesis summarizes knowledge in the field of vehicle aerodynamics and the principle of CFD simulations. The essence of the work is bonnet shape design of racing pneumobile Typhoon, developed at FME BUT, for lowest possible air resistance. CFD simulations are used to observe and analyse the influence of the bonnet shape on the aerodynamics properties. The designed shape solution of the bonnet significantly contributes to the reduction of aerodynamic drag compared to the existing bonnet. Thanks to this, the vehicle’s parameters are improved from maximum speed to the range. The acquired knowledge can also help in the further development of pneumobiles and in improving the setting of the computational model described in the work.
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Optimization of hydrostatic bearing recess shape
Kopřiva, David ; Omasta, Milan (referee) ; Michalec, Michal (advisor)
This bachelor's thesis deals with the problem of optimizing the recess shape of a hydrostatic bearing. It describes the principle of operation of hydrostatic bearings, their use and previous recess optimizations. A circular recess is considered as the reference geometry. This is firstly investigated by analytical calculation and CFD simulation. The results from the analytical calculation and from the calculation using the CFD simulation are then compared in terms of accuracy of CFD simulation. After verifying the CFD settings, three types of geometry are proposed based on research and previous studies, and with the help of CFD, these geometries are examined with respect to hydrostatic bearing load capacity and recess pressure. All proposed geometry types are then compared with the reference geometry. The results show that the reference geometry has the best results in terms of bearing load capacity and recess pressure. From the point of view of asymmetrical loading and damping, the use of the proposed geometries seems to be more appropriate. This thesis describes a detailed procedure for setting up the CFD and can serve as a basis for further optimization.
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Methods for measuring the geometrical tolerances
Juráňová, Bára ; Michalec, Michal (referee) ; Svoboda, Petr (advisor)
The bachleor’s thesis deals with the analysis of geometric tolerancing of machine parts. The work clarifies the terms and definitions of geometric tolerancing. Simultaneously, the specifications of measuring with measuring devices and gauges, can be found here. The work also proposes a method for aplication geometric tolerance, wich is apply to the shaft od radial fan. Subsequently, the measurement of the prescribed tolerances for this part is described.
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Tribological characteristics of smart fluids
Michalec, Michal ; Čermák, Jan (referee) ; Svoboda, Petr (advisor)
The master's thesis deals with experimental study of tribological characteristics of smart fluids. Smart fluids are substances in liquid state reacting to the presence of magnetic or electric field by change in rheological properties. For possible application in devices using conventional lubricants is necessary to choose suitable smart fluid and study the influence of excitation on formation of lubricating layer, friction and wear. Comprehensive description of excitation influence is executed using three experimental devices and theoretical model for measurements parameters specification. Assessed are lubricant film thickness, friction coefficient and wear under smart fluid activation in non-conformal contact. Results show significant observable influence of smart fluids excitation on all assessed aspects. Understanding the mechanisms of smart fluids excitation can be a key step in development of intelligent devices with active external control of lubricant behaviour and character, that could lead to maintenance cost reduction and effectivity improvement.
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