The motivation of the thesis is to decrease the time waste that is caused by repetitive processes during the first phase analyses of new launcher projects. Currently, the feasibility check of a launcher project consumes time and effort due to the communication traffic between many disciplines. The thesis provides a tool that performs the first analyses of custom launchers without the need of CAD modelling of the components. 3D Launcher Architecture Tool is developed to be able to analyze many different launcher architectures for advanced projects within a short time. To achieve that, a graphical user interface is developed that performs mass, center of gravity, and moments of inertia calculations; visualizes the launcher components with respect to the user’s input; and exports the data as text file that can be used in CATIA to autonomously model parts according to the output parameters from the tool. Even though there are comparable existing tools, none of them found 100% suitable for the ArianeGroup’s usage; thus, 3D Future Launcher Architecture Tool is created. It is capable of performing the fundamentally specified features, yet highly open for improvements.

This thesis reports the results of an investigation into the compressive strength of unidirectionally reinforced carbon fibre composites when loaded parallel to the fibres. A comprehensive review of previous research is presented and from this it is clear that no overall theory e,d.sts for predicting the unidirectional compressive strength of high volume fraction carbon composites. A study of the points raised in the survey led to the postulation of a three dimensional analytical model based on energy considerations, which provides substantial insights into the behaviour of unidirectional composite under compressive load. Strength predictions were made using the results of this three dimensional model and .the finite element analysis of the composite micro-structure, the latter providing infoxmation about the stress state at the fibre matrix interface, Different techniques used for measuring the unidirectional compressive strength of carbon fibre reinforced plastic are compared, since the published data shows a considerable variability between methods. This comparison was carried out at an analytical level, using MSC-Nastran finite element analysis software and at an experimental level by comparative testing. Using the optimum test technique selected from these results, measurements were made on XAS/91 1+, T300/914 and HMS/914 composite with and without absorbed moisture. These were then compared to the strength predictions made from the model a good fit being shown for dry composite strength predictions.

This thesis investigates what design of a large UAV performing VTOL using only electrical motors is the most viable in terms of extending its range. Because it uses batteries for power, its powered time is limited, posing the need for a way of extending its flight time. By using a tiltwing design, its vertical flight time is cut at the same time as it will be able to perform as a glider, increasing its range drastically. To achieve the best lift-to-drag ratio, the high-lift F3B RG15-airfoil was chosen, giving the UAV a lift-to-drag ratio of 36,48, and a maximum range per descend glide of approximately 25,5 kilometers. The fuselage will be a simple, aerodynamic body just big enough to hold the batteries and the load while giving the wing the ability to tilt without interfering with the rotors. The material used in this thesis comes from a company which produces high-strength carbon fiber tubes and rods as well as a 3k twill weave carbon fiber prepreg for the skin, making the structure as light and strong as possible. The result is an aircraft with a structural weight of 56,6 kilograms that is strong enough to lift with a combined weight of 495 kilograms and at the same time perform a safe glide flight.

<p> Combustion in scramjet engines is faced with the limitation of brief residence time in the combustion chamber, requiring fuel and preheated air streams to mix and ignite in a matter of milliseconds. Accurate predictions of autoignition times are needed to design reliable supersonic combustion chambers. Most efforts in estimating non-premixed autoignition times have been devoted to hydrogen-air mixtures. The present work addresses hydrocarbon-air combustion, which is of interest for future scramjet engines. </p><p> Computation of ignition in supersonic flows requires adequate characterization of ignition chemistry and description of the flow, both of which are derived in this work. In particular, we have shown that activation energy asymptotics combined with a previously derived reduced chemical kinetic mechanism provides analytic predictions of autoignition times in homogeneous systems. Results are compared with data from shock tube experiments, and previous expressions which employ a fuel depletion criterion.</p><p> Ignition in scramjet engines has a strong dependence on temperature, which is found by perturbing the chemically frozen mixing layer solution. The frozen solution is obtained here, accounting for effects of viscous dissipation between the fuel and air streams. We investigate variations of thermodynamic and transport properties, and compare these to simplified mixing layers which neglect these variations. Numerically integrating the mixing layer problem reveals a nonmonotonic temperature profile, with a peak occurring inside the shear layer for sufficiently high Mach numbers.</p><p> These results will be essential in computation of ignition distances in supersonic combustion chambers.</p><p>

<p> Due to millions of years of evolution, sharks have evolved to become quick and efficient ocean apex predators. Shark skin is made up of millions of microscopic scales, or denticles, that are approximately 0.2 mm in size. Scales located on the shark&rsquo;s body where separation control is paramount (such as behind the gills or the trailing edge of the pectoral fin) are capable of bristling. These scales are hypothesized to act as a flow control mechanism capable of being passively actuated by reversed flow. It is believed that shark scales are strategically sized to interact with the lower 5% of a boundary layer, where reversed flow occurs at the onset of boundary layer separation. Previous research has shown shark skin to be capable of controlling separation in water. This thesis aims to investigate the same passive flow control techniques in air. </p><p> To investigate this phenomenon, several sets of microflaps were designed and manufactured with a 3D printer. The microflaps were designed in both 2D (rectangular) and 3D (mirroring shark scale geometry) variants. These microflaps were placed in a low-speed wind tunnel in the lower 5% of the boundary layer. Solid fences and a flat plate diffuser with suction were placed in the tunnel to create different separated flow regions. A hot film probe was used to measure velocity magnitude in the streamwise plane of the separated regions. The results showed that low-speed airflow is capable of bristling objects in the boundary layer. When placed in a region of reverse flow, the microflaps were passively actuated. Microflaps fluctuated between bristled and flat states in reverse flow regions located close to the reattachment zone.</p><p>

No description available.

No description available.

Abstract Aircraft maintenance within the aviation industry is an essential part as the purpose is to maintain the aircrafts built-in security and reliability levels. Aircraft require approved and straightforward maintenance to ensure safe operation and airworthiness. The maintenance program's intention is to ensure that a function operates properly despite an uncertain environment. During flights, aircraft are exposed to a large number of loads, which causes components and parts to be affected negatively. Because of this, a maintenance program is presented, the program tries to constantly detect and correct any potential errors before a functional error occurs. This degree project is about finding out about the pros and cons of extending or shortening the maintenance interval within the aircraft maintenance program. In addition, the purpose is to draw conclusions about how airline, aircraft turbine performance and age are related to extension or shortening of this maintenance interval. The dissertation was written at the Academy of Innovation, Design and Technology at Mälardalens högskola, Västerås. The work process was carried out in several steps. The first step was to deepen the knowledge within the field and understand the maintenance program. This was done through literature studies and information gathering on the subject. The second step was to analyze and process the general information and answers from the interview questions. The work included the advantages and disadvantages caused by extension or shortening of maintenance intervals without affecting the reliability that maintenance requirements ensure. / Sammanfattning Underhåll av flygplan inom en flygverksamhet är en väsentlig del då avsikten är att bevara planets inbyggda säkerhets- och tillförlitlighetsnivåer. Flygplan kräver ett godkänt och rätthanterligt underhåll för att det ska kunna opereras på ett säkert samt luftvärdigt sätt. Underhållsprogrammets avsikt är att garantera att en funktion opererar korrekt trots en osäker miljö. Under flygningar utsätts flygplan för ett stort antal belastningar vilket leder till att komponenter och delar påverkas negativt. Ett underhållprogram försöker ständigt hitta och uträtta potentiella fel innan det uppstår ett funktionellt fel. Detta examensarbete handlar om att ta reda på vilka för- och nackdelar det finns med att förlänga eller förkorta underhållsintervall inom flygets underhållsprogram. Syftet är dessutom att dra slutsatser angående om hur flygbolag, flygplanets motorprestanda och ålder har ett samband vid förlängning eller förkortning av detta underhållsintervall. Examensarbetet skrevs på akademin för Innovation, Design och Teknik vid Mälardalens högskola, Västerås. Arbetsprocessen utfördes i flera olika steg. Första steget i arbetet var att fördjupa sig inom området och förstå sig på flygets underhållsprogram. Detta gjordes med hjälp av litteraturstudie och informationsinsamling inom ämnet. Därefter bearbetades den insamlade informationen och svaren från intervjufrågorna till arbetets resultat. Arbetet resulterade bland annat till vilka för- och nackdelar som medförs genom att förlänga eller förkorta underhållsintervallen utan att det påverkar driftsäkerheten som underhållskraven säkerställer.

In this Master Thesis, numerical models of ADCS components are performed. The models will be used in the design of the first 3U CubeSat of the CSU Montpellier, the ROBUSTA 3-A. The goal of the thesis is to develop numerical models of angular rate sensors and reaction wheels and to obtain relevant information of these components in the context of the R-3A mission. Firstly, the state-of-the-art of models are outlined, and the most suitable are chosen. Secondly, assumptions are made, and the models are implemented. Next, the models are parametrized for specific elements to be used on R-3A. Lastly, the models are validated and simulated. The results of simulations confirm a choice of the CoTS components for the R3A mission. Besides, the results provide information about system performance parameters such as RW acceleration time, maximum satellite speed, and attitude knowledge accuracy in eclipse.

The main purpose of this research is to understand various aspects of the solar wind plasma interaction with the Earth's Moon by the means of kinetic computer simulations. The Moon is essentially a non-conducting object, that has a tenuous atmosphere and no global magnetic field. Then the solar wind plasma impacts the lunar surface, where it is absorbed or neutralized for the most part. On average about 10% of the solar wind protons reflect in charge form from lunar crustal magnetization and up to 20% reflect from the lunar surface as neutral atoms.First we consider the Moon to be a perfect plasma absorber and we study the global effects of the solar wind plasma interaction with the Moon using a three-dimensional self-consistent hybrid model. We show that due to the plasma absorption in the lunar dayside, a void region forms behind the Moon and a plasma wake forms downstream. Then we study different parameters that control the lunar wake, discuss various mechanisms that fill in the wake, and compare our simulations with observations. We also discuss the effects of lunar surface plasma absorption on the solar wind proton velocity space distribution at close distances to the Moon in the lunar wake. Moreover, we show that three current systems form in the wake that enhance the magnetic fields in the central wake, depress the fields in the surrounding areas, and confine the fields and plasma perturbations within a Mach cone. Finally we study the effects of protons reflected from lunar crustal magnetic fields on the global lunar plasma environment. We show that the reflected protons interact with the solar wind plasma, compress the fields and plasma upstream in the lunar dayside and downstream outside the Mach cone. The conclusion of this thesis work is that the solar wind plasma interaction with the Moon is dynamic and complex. This is, however, due to the kinetic nature of this interaction because of the scales of the interaction regions where the Magnetohydrodynamics (fluid) approach cannot address the detailed physics. This reveals the importance of kinetic modeling to understand this interaction. The results of this study will feed forward to human space exploration, kinetic theories of plasma interaction with airless bodies, and fundamental plasma physics processes. / Godkänd; 2014; 20140325 (shafat); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Shahab Fatemi Ämne: Rymdteknik/Space Technology Avhandling: Kinetic Modeling of the Solar Wind Plasma Interaction with the Moon Opponent: Lektor Geraint Jones, Mullard Space Science Laboratory, Department of Space & Climate Physics, University College London, Dorking, Surrey Ordförande: Docent Mats Holmström, Avd för rymdteknik, Institutionen för system- och rymdteknik, Luleå tekniska universitet/Institutet för rymdfysik, Kiruna Tid: Torsdag den 22 maj 2014, kl 10.00 Plats: Aula, Institutet för rymdfysik, campus Kiruna, Luleå tekniska universitet