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Fatigue Crack Growth Retardation Techniques for the Integral Airframe Structure
Jetela, Václav ; Růžička, Milan (referee) ; Petrásek, Miloslav (referee) ; Klement, Josef (advisor)
Při zavádění integrální letecké konstrukce vyvstal problém s rychlým růstem únavové trhliny v této konstrukci. Jednou z možností, jak zpomalit růst trhliny a zvýšit životnost konstrukce, je aplikace tzv. zastavovače trhliny. Tato disertační práce porovnává aditivně vyráběné a lepené zastavovače trhlin z hlediska životnosti, rychlosti šíření trhliny a delaminace. V případě lepených zastavovačů trhlin; doposud nebyla věnována pozornost zastavovačům z nerezové oceli. Nerezová ocel se jeví jako vhodný kandidát z důvodu koeficientu tepelné roztažnosti blízkého hliníkové slitině, vysoké tahové pevnosti a vysokého modulu pružnosti v tahu. S ohledem na aditivně vyráběné zastavovače trhlin, žádná pozornost nebyla věnována zastavovačům trhlin z materiálů odlišných od podkladové konstrukce. Za účelem doplnění současného stavu poznání byly vybrány tyto aditivní technologie: studená kinetizace a ultrazvuková konsolidace. Metodou studené kinetizace byly deponovány zastavovače z nerezové oceli a titanové slitiny. Metodou ultrazvukové konsolidace byly navařeny zastavovače z nerezové oceli. V experimentální části práce byl pozorován růst únavové trhliny v podkladové konstrukci. Delaminace zastavovače byla monitorována metodou pulzní termografie s následnou rekonstrukcí termografického signálu. Lepené zastavovače trhlin z nerezové oceli se prokázaly jako vhodná alternativa k zastavovačům s uhlíkovými vlákny. Nerezové zastavovače výrazně snížily rychlost šíření únavové trhliny, čímž značně prodloužily životnost vzorku. Bohužel, všechny zastavovače připravené metodou studené kinetizace urychlily růst únavové trhliny, čímž došlo k předčasnému selhání vzorku. Ultrazvukově konsolidované zastavovače s dvěma vrstvami oceli byly nejefektivnější z hlediska zvýšení životnosti. Tato práce navíc prokázala, že pro detekci delaminace v ultrazvukově konsolidovaném laminátu je možné použít metodu pulzní termografie.
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Space Debris
Kvačová, Kristýna Kateřina ; Konečný, Pavel (referee) ; Petrásek, Miloslav (advisor)
The theoretical part of the diploma thesis focuses on the characterization of the artificial space debris in Earth's orbit. The methods of debris removal, the space debris mitigation guidelines, and related international documents are elaborated. In addition to, detection and monitoring of the orbital population are briefly described. The practical part of the thesis proposes a new method of debris removal which is aimed at CubeSat after mission ending in low earth orbit. The method consists of deorbiting maneuver, which is calculated, and the solid rocket motor for the maneuver performance. This includes the computation of dimensions of the solid rocket motor and the propellant configuration.
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Materials for space technology
Bačová, Alena ; Tříska, Václav (referee) ; Petrásek, Miloslav (advisor)
This master´s thesis is dealing with an analysis of materials used for space technology. The thesis is divided into eight main parts. The first part defines space technology. The second part introduces the issue of designing satellites and planning the space mission. The third part describes the effects of the environment on space technology before launch, during launch and flight, in space, and during atmospheric entry. The fourth part introduces the most used standards in Europe for the space industry. The fifth part analyses materials and their application in the space industry. The sixth part provides an overview of aerospace materials tests. The seventh part analyse processes and damage of material during and after the impact of a small object. The last part is devoted to the preliminary design of the device for a more accurate analysis of the behaviour of the material during the impact of a small object.
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Historical development of rocket engines
Šima, Dávid ; Dubnický, Lukáš (referee) ; Petrásek, Miloslav (advisor)
This bachelor´s thesis is dealing with the historic development of rocket engines and their use on rocket carriers. The work is divided into eight parts. The first part describes the principle of operation of reactive motion and derivation of the Ciolkovskij equation. The second part describes historical development from ancient China to the period before World War II. The fourth part describes the Second World War and especially the missile development in Germany during the war. The fifth part describes mainly rocket engines use in space research of the USA, Russia, Japan, the European Space Agency, India and China. The sixth part describes rocket engines of private companies which were founded in the early 21. century. The seventh part describes aerospike rocket engines and the last part describes physical engines.
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Analysis of transport aircraft damage during of terrorist attack
Čížková, Markéta ; Jetela, Václav (referee) ; Petrásek, Miloslav (advisor)
In its theoretical part, the diploma thesis deals with the reasons leading to terrorist attacks and a brief list of some attacks on aircraft. It also focuses on the aircraft as the target of a terrorist attack, especially the aircraft kite as the major researched part. The conclusion of the theoretical part summarizes a list of types of aircraft fuselage structures in respect of design solutions for load transfer. The practical part determines the extent of damage caused by a missile with a fragmentation warhead. This scope is then applied to the illustrative case. In the following chapters, the calculation of the critical force of a panel loaded with pressure depends on the different nature and extent of damage. Then the work highlights the evaluation of the obtained results, which are also summarized in the conclusions of the work.
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Design of the six seat helicopter with one turboshaft engine
Nasibullin, Bulat ; Tříska, Václav (referee) ; Petrásek, Miloslav (advisor)
The aim of this work is to develop a preliminary design of a six-seat helicopter with a turboshaft engine. The preliminary design of the helicopter consists of processing statistical data on similar helicopters, which are then, based on the specified requirements, used to estimate the basic weight parameters of the helicopter, the main geometric parameters and to determine the type and power of the propulsion unit. It consists of calculations of basic geometric parameters of the aircraft and engine selection. Part of another solution is the aerodynamic calculation of the supporting rotor, from which both the performance of the helicopter in suspension and in forward flight flow. In a special part of the project, the attention is paid to the system of balancing the reaction torque, in this case fenestrone and the solution is supplemented by some specific means installed on the tail beam, which help to balance the reaction torque and improve the directional control parameters of the helicopter.
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An overview of atmospheric carriers for launching satellites into Earth's orbit
Bačová, Alena ; Petrásek, Miloslav (referee) ; Daněk, Vladimír (advisor)
This bachelor´s thesis is dealing with an overview of aircrafts designed as a launch platform for an air launch of satellite into the low Earth orbit. The thesis is divided into four main parts. The first part describes main principles of reaction engine and its two types of engines. The second part provides an overview of aircrafts as launch platform in the USA. The third part deals with these launch platforms in the former SSSR. The fourth part is devoted to aircrafts as launch platform in the Europe.
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Design of single - engine, multi - purpose transport airplane in the CS / FAR category 23
Majtán-Černák, Tomáš ; Petrásek, Miloslav (referee) ; Píštěk, Antonín (advisor)
This diploma thesis deals with a design of single-engine, multi-purpose, transport airplane in Normal category, given by CS/FAR 23. Design is created in highest constructional and technological accordance with L 410 airplane series. Thesis determines airplanes conceptual layout, basic dimensions, basic weight and center of gravity analysis, aerodynamic and aerostatic foundation, flight performances and airplane properties. Thesis arranges various versions of cabin layouts and describes power plant installation and landing gear construction. Results of the thesis shows, that this design is advantageous in various aspects. Design is comparable with competition from perspective of its performances. Financial analysis showed, that costs of development are returnable in relatively low amount of sold airplanes, for a prices, that are lower than a prices, competition is selling similar airplanes for. Moreover, costs of maintenance are expected to be low, as a consequence of using only one engine unit.
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Age forming of aluminium alloys
Stanislav, Filip ; Petrásek, Miloslav (referee) ; Klement, Josef (advisor)
The diploma thesis is focused on the description and the verification of a relatively young creep age forming method. This method is based on a relaxation of stress and a creep of material, which occur by forming a part in the clamping tool during the artificial precipitation heat treatment at elevated temperature. After removing from the tool, the spring back and the residual stresses in the part are smaller compared to the conventional forming methods. This is mainly reflected in the increased fatigue resistance of the structure. The creep aging is only applicable to the precipitation heat treatable alloys. This thesis is focused on aluminium alloys, which are typical for the aerospace industry. The first part of the thesis describes principles of technology, its use in the aviation and material processes in the aluminium precipitation heat treatable alloys during the creep age forming. In the second part, there is a methodology of the verification of technology on samples made of the aluminium alloys ČSN EN AL-P 7075 and ČSN 424203 (approximate equivalent of ČSN EN AL-P 2024). Furthermore, a forming tool is designed, and experiments are performed according to the proposed methodology. At the end of the thesis, the experiments are evaluated and changes in the spring back of the samples are compared for three different methods of forming: the conventional cold clamping forming, the creep age forming and the creep age forming with an overaging.
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Modern Maintenance Procedures for Airframe Inspections for General Aviation Category Aircraft
Koštial, Rostislav ; Petrásek, Miloslav (referee) ; Třetina, Karel (referee) ; Hlinka, Jiří (advisor)
Aircraft scheduled maintenance requirements are rapidly extending and developing due to rapid evolution of small aircraft. This evolution leads to implementation of until recently exclusively airliner class maintenance standards. In the field of general aviation and FAR 23/ EASA CS-23 especially, preventive maintenance based on part replacing or repairing is still dominant. DAMAGE TOLERANCE philosophy implementation into an aircraft design influences maintenance procedures, which are adjusted to older SAFE LIFE philosophy. Aircraft manufactures are developing new ways, how to integrate requirements of damage tolerance application into scheduled maintenance procedures. Huge airliner manufactures (FAR 25/ CS-25) are using the ATA MSG-3 intelligent maintenance approach based on inspection. This dissertation thesis develops intelligent scheduled maintenance methodology, utilizing ATA MSG-3 procedures, expert knowledge and Multiple Criteria Decision Analysis (MCDA).
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