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Proposal for technological layout of machines in a milling room of a mechanical engineering company Tirad
Dohnal, Tomáš ; Navrátil, Petr (referee) ; Kubík, Roman (advisor)
Tirad, a metal machining company, plans to build a new hall as an extension of its operation. This paper deals predominantly with production flow analysis of present operation. The analysis draws upon literary study and the company's previous production experience. Possible placement of machines is suggested in the following part of the paper, based on the analysis and requirements of the company. The fundamental requirement is to separate roughing and finishing technological operations, moving the latter completely into the new hall. The deployment of machines is optimized with regard for materiál flow. The new hall's dimensions are outlined in a drawing. Three options of machine deployment are discussed. In conclusion, these options are compared to one another and also to the present state.
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Stress-strain analysis of the axial turbine of turboprop engine
Kolárik, Matej ; Ing. Petr Navrátil, Ph.D (referee) ; Skalka, Petr (advisor)
This diploma thesis deals with a creation and subsequent analysis of the computational model of the turboprop engine's turbine designed by Prvá Brněnská Strojírna Velká Bíteš. The computational model is created and solved in the finite element model system ANSYS. A cyclic symmetry is taken into account during the solution. The static analysis of the turbine was carried out in objective to quatify prestress effects which are caused by a rotation, higher temperature and an excitation from stator blades. These prestress effects were used in the modal analysis of the turbine. Harmonic analysis were calculated to simulate an operation conditions and a resonance state. The results of these analysis indicate that the higher temperature has the biggest impact on the properties of the turbine. It is also shown, that during the operation of the engine the turbine runs in the mode which is not even close to the resonance state.
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Homogenization of closed foam structures using Kelvin cell
Škoviera, Jozef ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor‘s thesis deals with creating calculation model of the foam structure based on Kelvin cell with closed porosity. First aim of this work is homogenization of the foam structure by identical deformation response in foam structure and continuum. Second aim is follow-up parametrical study of influence of characteristic measures of Kelvin cell on material characteristics. Task was solved in ANSYS software by method of final elements. Resultant dependences rendering was done in MATLAB software.
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Inverter 12 V DC to 230 V AC with Protection
Navrátil, Petr ; Šilhavý, Pavel (referee) ; Kubánek, David (advisor)
This bachelor thesis deals with converter, which alters 12 V of direct input Voltage to 230 V of alternating Voltage output with frequency of 50 Hz. Introduction describes the basic parting of convertors. The chosen concept of designed convertor was based on that chapter. The practical part describes construction of this convertor including necessary safety shielding. At the end, the construction of the converter was tested by practical measuring and it was proven that the result meets with required values with slight anomaly.
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Vibration diagnostics of bearings
Navrátil, Pavel ; Mazal, Pavel (referee) ; Klapka, Milan (advisor)
This bachelor’s thesis introduces the basic principles of vibrodiagnostic methods and their importance for individual fase of bearing’s damage. The selected methods studied are: acoustic emission, SPM (shock pulse method), SEE (spectral emission energy), envelope method, High frequency emission, Crest factor, Kurtosis factor and special method for slow-motion machines Adash Compressed Time.
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Modelling of the randomly formed ceramic foam structure for FEM simulations
Papšík, Roman ; Navrátil, Petr (referee) ; Ševeček, Oldřich (advisor)
This bachelor thesis deals with construction of ceramic foam model with various levels of (ir)regularity for finite element simulations in Ansys. The main objective is to substitute the complex structure of the open cell foam using the beam elements, enabling to perform FE analysis on much larger volumes of foams than the realistic foam models composed of solid elements. In this work, the technique of the model creation is based on the Voronoi tessellation and enables choice of arbitrary (ir)regularity of the modelled structure. The created source codes generate the model data directly in the syntax of APDL language for FEM system Ansys. The first part of the work describes several methods of the space partitioning and methods for substitution of the real foam structure by simplified “wire” model. The second part defines the Voronoi tessellation (diagram) as a key technique for creation of the foam model and describes its algorithms. The next part of the work deals with possibilities and utilizations of various software and libraries, describes creation of the own code in mathematical software Matlab and way how to transfer the model data into the system Ansys. The last part of the work demonstrates functionality of the created model on several FEM simulations, studying response of the ceramic foam on the external mechanical loading, upon consideration of various levels of the foam structure irregularity.
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Regulation of DC hub dynamo
Navrátil, Petr ; Knobloch, Jan (referee) ; Huták, Petr (advisor)
The aim of this bachelor’s thesis is the theoretical preparation, design and implementation of a DC converter for a bicycle charge dynamo with compensation for its large inductance. The designed converter will be able to use the maximal power of the dynamo.
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