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Conceptual design of a manned mobile lunar habitat (vehicle)
Mikeš, Adam ; Porteš, Petr (referee) ; Šálený, Vratislav (advisor)
Bakalářská práce se zabývá konstrukcí lunárního vozidla. V práci jsou popsány případy reálného použití lunárního vozidla. Dála se práce zabývá konstrukcí podvozku lunárního vozidla. Úkolem konstrukční části je návrh ideálního podvozku pro měsíční povrch s důrazem na hmotnost a jednoduchost provedení. Konstrukční řešení jsou následně podrobena analýze za účelem dosáhnutí efektivních výsledků.
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Pevnostní posouzení konstrukce výřezu dveří přetlakovatelného habitatu pro extrémní prostředí
Sláma, David ; Šálený, Vratislav (referee) ; Návrat, Tomáš (advisor)
Main goals of this master thesis are following: to perform the state of the art research of overpressure constructions (especially space habitats, plane fuselages); to create an own concept of the functional inside ending (hole) in the sandwich panel for a door; to perform stress-strain analysis of this concept; to perform the design optimalization of this concept in order to minimise the weight. To solve the problems above software Ansys 17.2 is chosen, because it allows to: model the material of the honeycomb core of sandwich panel as homogenous linear orthotropic material; evaluate reserve factors of all critical limit states; perform the design optimalization; perform Monte Carlo simulation. First and second design optimalizations discover, that with defined parameters: 0,635 mm width of aluminium sandwich face sheets and inner overpressure 0,1 MPa, a creation of the model, that would be safe by changing the values of design variables is not possible. Specifically, the maximum value of shear stress on the glued areas between aluminium face sheets and honeycomb core is higher than the shear strength of the glue. Therefore, two new concepts are created. First for inner pressure 0,03 MPa and bigger width of aluminium face sheets 3,175 mm, second for inner pressure 0,02 MPa and same width of aluminium face sheets 0,635 mm. For both these concepts, an overall reserve factor is calculated. First, the value of an overall reserve factor is calculated deterministically. Secondly, the value of an overall reserve factor is calculated stochastically considering the variance of material properties of the honeycomb core ± 10 % by Monte Carlo simulation. An overall reserve factor of the concept with inner pressure 0,02 MPa is determined as 1,21. An overall reserve factor of the concept with inner pressure 0,03 MPa is determined as 1,20. The weight of the concept for inner pressure 0,03 MPa is though 4 times bigger than the weight of the concept for inner pressure 0,02 MPa. In the concept for inner pressure 0,02 MPa the maximum value of HMH stress in aluminium components is critical, stochastically considered material properties of the honeycomb core don’t have a significant influence on this value. In the concept for inner pressure 0,03 MPa the value of maximum shear stress on the glued areas between aluminium face sheets and the honeycomb core is critical, stochastically considered material properties of the honeycomb core have a significant influence on this value. In the concept for inner pressure 0,03 MPa an absolute error of overall reserve factor is 8 % (overall reserve factor calculated deterministically was 1,28) which is significant. Monte Carlo simulation is also used to find that the value of Poisson ratio XY of the honeycomb core doesn’t have statistically significant influence on all limit states. Value of the reserve factor of the honeycomb core is higher than 2 in both concepts. Monte Carlo simulation discovers that this value can be significantly lower. Using Tsai-Wu failure criteria the reserve factor in the concept for inner pressure 0,02 MPa is determined as 2,72 deterministically x 2,41 stochastically (absolute error 31 %), in the concept for inner pressure 0,03 MPa the reserve factor is determined as 6,85 deterministically x 6,17 stochastically (absolute error 68 %).
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Numerical Simulation of Noise Generated by Shear Layer Instabilities
Šálený, Vratislav ; Kozubková, Milada (referee) ; Paur, František (referee) ; Tippner,, Jan (referee) ; Katolický, Jaroslav (advisor)
Predicting and inhibiting aerodynamically generated noise for fast moving vehicles such as cars, aircraft and trains is increasingly important. The tonal noise generated by the shear-layer instability of air flowing around the cavity opening is especially one of the most significant and most intense sources of aerodynamically generated noise. Computational aeroacoustics (CAA) based on the CFD simulations of compressible Navier-Stokes equations offers the most general approach to predicting those aerodynamically induced sounds. Aeroacoustics is practically always associated with turbulent flow and turbulence is the major challenge for CFD simulations. Four different turbulence modelling approaches are examined in this work. Three of them belong to the LES method category and one uses the URANS approach. Appropriate numerical discretization and iteration schemes have been identified for each of these approaches and implemented in the OpenFOAM open source CFD platform. The accuracy, computational performance and convergence reliability of those schemes have been subsequently studied during three-dimensional CFD simulations on a model of a suitable real object. The CFD simulation results are validated by a measurement. An organ pipe has been chosen as the object of this CAA research because it uses self-sustained oscillations, commonly referred as shear-layer (Rossiter) modes, as the source of its tone generation. The numerical simulation of the shear layer modes, respectively the noise generated by instability in the shear layer, is the subject of this work.
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Computation of race car aerodynamics
Vančura, Jan ; Šálený, Vratislav (referee) ; Porteš, Petr (advisor)
The main subject of this diploma thesis is computation of race car aerodynamics. It describes composition method of CFD model with utilization of 3D scanner ATOS and CAD software Pro Engineer. During creating this diploma thesis were found influences of additional aerodynamics components of racing car on globally axle loads.
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Conceptual habitat design for extreme environments - spacesuit design for Mars
Ponka, Jakub ; Lazar, Václav (referee) ; Šálený, Vratislav (advisor)
This bachelor’s thesis deals with the conceptual design of a spacesuit for conditions on Mars. The concept is based on the reaserch part, in which are described current space suit models of different space agencies and extreme conditions on Mars. In the design itself, the emphasis is on weight reduction. This is why materials such as titanium or carbon fiber are used. Also technology for producing oxygen from atmospheric carbon dioxide and digitalization of user interface is used. At the end, the thesis addresses the issue of metabolic heat dissipation from the suit’s internal atmosphere to the surrounding environment.
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Conceptual habitat design for extreme environments - two-person crew module design for NRHO
Valo, Patrik ; Horák, Marek (referee) ; Šálený, Vratislav (advisor)
Táto práca predstavuje komplexný koncepčný návrh lunárneho obytného modulu, ktorý obieha okolo Mesiaca v blízkosti jeho takzvanej NRHO, s implementáciou nafukovacích materiálov. Obytný modul zabezpečuje zdravé prostredie pre dvojčlennú posádku astronautov, ktorá vykonáva experimenty počas 30-dňového pobytu na palube. Návrh modulu zahŕňa rozmerové parametre modulu, zloženie materiálov, funkcie systému pre podporu života, odhad tepelných vlastností, rozmery a umiestnenie solárnych panelov, spôsob komunikácie, vnútorné vybavenie, výpočet celkovej hmotnosti, pobyt orbity a spôsobu pre udržanie na orbite. Táto práca vie prispieť k výskumu Mesiaca a prítomnosti ľudstva vo vesmíre, poskytujúc sľubný dizajn modulu pre možné budúce misie a rozšírenie našich vedomostí o prostredí Mesiaca.
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Numerical Simulation of Noise Generated by Shear Layer Instabilities
Šálený, Vratislav ; Kozubková, Milada (referee) ; Paur, František (referee) ; Tippner,, Jan (referee) ; Katolický, Jaroslav (advisor)
Predicting and inhibiting aerodynamically generated noise for fast moving vehicles such as cars, aircraft and trains is increasingly important. The tonal noise generated by the shear-layer instability of air flowing around the cavity opening is especially one of the most significant and most intense sources of aerodynamically generated noise. Computational aeroacoustics (CAA) based on the CFD simulations of compressible Navier-Stokes equations offers the most general approach to predicting those aerodynamically induced sounds. Aeroacoustics is practically always associated with turbulent flow and turbulence is the major challenge for CFD simulations. Four different turbulence modelling approaches are examined in this work. Three of them belong to the LES method category and one uses the URANS approach. Appropriate numerical discretization and iteration schemes have been identified for each of these approaches and implemented in the OpenFOAM open source CFD platform. The accuracy, computational performance and convergence reliability of those schemes have been subsequently studied during three-dimensional CFD simulations on a model of a suitable real object. The CFD simulation results are validated by a measurement. An organ pipe has been chosen as the object of this CAA research because it uses self-sustained oscillations, commonly referred as shear-layer (Rossiter) modes, as the source of its tone generation. The numerical simulation of the shear layer modes, respectively the noise generated by instability in the shear layer, is the subject of this work.
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Pevnostní posouzení konstrukce výřezu dveří přetlakovatelného habitatu pro extrémní prostředí
Sláma, David ; Šálený, Vratislav (referee) ; Návrat, Tomáš (advisor)
Main goals of this master thesis are following: to perform the state of the art research of overpressure constructions (especially space habitats, plane fuselages); to create an own concept of the functional inside ending (hole) in the sandwich panel for a door; to perform stress-strain analysis of this concept; to perform the design optimalization of this concept in order to minimise the weight. To solve the problems above software Ansys 17.2 is chosen, because it allows to: model the material of the honeycomb core of sandwich panel as homogenous linear orthotropic material; evaluate reserve factors of all critical limit states; perform the design optimalization; perform Monte Carlo simulation. First and second design optimalizations discover, that with defined parameters: 0,635 mm width of aluminium sandwich face sheets and inner overpressure 0,1 MPa, a creation of the model, that would be safe by changing the values of design variables is not possible. Specifically, the maximum value of shear stress on the glued areas between aluminium face sheets and honeycomb core is higher than the shear strength of the glue. Therefore, two new concepts are created. First for inner pressure 0,03 MPa and bigger width of aluminium face sheets 3,175 mm, second for inner pressure 0,02 MPa and same width of aluminium face sheets 0,635 mm. For both these concepts, an overall reserve factor is calculated. First, the value of an overall reserve factor is calculated deterministically. Secondly, the value of an overall reserve factor is calculated stochastically considering the variance of material properties of the honeycomb core ± 10 % by Monte Carlo simulation. An overall reserve factor of the concept with inner pressure 0,02 MPa is determined as 1,21. An overall reserve factor of the concept with inner pressure 0,03 MPa is determined as 1,20. The weight of the concept for inner pressure 0,03 MPa is though 4 times bigger than the weight of the concept for inner pressure 0,02 MPa. In the concept for inner pressure 0,02 MPa the maximum value of HMH stress in aluminium components is critical, stochastically considered material properties of the honeycomb core don’t have a significant influence on this value. In the concept for inner pressure 0,03 MPa the value of maximum shear stress on the glued areas between aluminium face sheets and the honeycomb core is critical, stochastically considered material properties of the honeycomb core have a significant influence on this value. In the concept for inner pressure 0,03 MPa an absolute error of overall reserve factor is 8 % (overall reserve factor calculated deterministically was 1,28) which is significant. Monte Carlo simulation is also used to find that the value of Poisson ratio XY of the honeycomb core doesn’t have statistically significant influence on all limit states. Value of the reserve factor of the honeycomb core is higher than 2 in both concepts. Monte Carlo simulation discovers that this value can be significantly lower. Using Tsai-Wu failure criteria the reserve factor in the concept for inner pressure 0,02 MPa is determined as 2,72 deterministically x 2,41 stochastically (absolute error 31 %), in the concept for inner pressure 0,03 MPa the reserve factor is determined as 6,85 deterministically x 6,17 stochastically (absolute error 68 %).
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Computation of race car aerodynamics
Vančura, Jan ; Šálený, Vratislav (referee) ; Porteš, Petr (advisor)
The main subject of this diploma thesis is computation of race car aerodynamics. It describes composition method of CFD model with utilization of 3D scanner ATOS and CAD software Pro Engineer. During creating this diploma thesis were found influences of additional aerodynamics components of racing car on globally axle loads.
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