Composite materials like carbon fiber-reinforced polymers (CFRPs) present highly appealing material properties, as they can combine high strength with low weight. In aerospace applications, these properties help to realize lightweight designs that can reduce fuel consumption. Within the aerospace industry, the use of these types of materials has increased drastically with the introduction of a new generation of commercial aircraft. This increased use of CFRP drives a need to develop more rational manufacturing methods. For aerospace applications, CFRP products are commonly manufactured from a material called prepreg, which consists of carbon fibers impregnated with uncured polymer resin. There are two dominant manufacturing technologies for automated manufacturing using prepreg, automated tape layup and automated fiber placement. These two technologies are not suitable for all types of products, either due to technical limitations or a combination of high investment costs and low productivity. Automation alternatives to the two dominant technologies have been attempted, but have so far had limited impact. Due to the lack of automation alternatives, manual manufacturing methods are commonly employed for the manufacturing of complex-shaped products in low to medium manufacturing volumes. The research presented in this thesis aims to explore how automated manufacturing systems for the manufacturing of complex CFRP products made from prepreg can be designed so that they meet the needs and requirements of the aerospace industry, and are suitable for low to medium production volumes. In order to explore the area, a demonstrator-centered research approach has been employed. A number of demonstrators, in the form of automated manufacturing cells, have been designed and tested with industrial and research partners. The demonstrators have been used to identify key methods and technologies that enable this type of manufacturing, and to analyze some of these methods and technologies in detail. The demonstrators have also been used to map challenges that affect the development of enabling methods and technologies. Automated manufacturing of products with complex shapes can be simplified by dividing the process into two steps. Thin layers of prepreg are laid up on top of each other to form flat laminates that are formed to the desired shape in subsequent forming operations. The key methods and technologies required to automate such a system are methods and technologies for automated prepreg layup, the automated removal of backing paper and the forming of complex shapes. The main challenges are the low structural rigidity and tacky nature of prepreg materials, the extensive quality requirements in the aerospace industry and the need for the systems to handle a wide array of prepreg shapes. The demonstrators show that it is possible to automate the manufacturing of complexshaped products using automated layup and forming of prepreg laminates. Tests using the demonstrators indicate that it is possible to meet the quality requirements that apply to manual manufacturing of similar products. / Polymera kolfiberkompositer erbjuder en eftertraktad kombination av låg vikt och högstyrka som kan bidra till lättviktskonstruktioner som t.ex. kan leda till bränslebesparingarför passagerarflygplan. Inom flygindustrin har användningen av denna materialtyp ökatkraftigt med introduktionen av en ny generation flygplan som till mer än hälften består avkompositmaterial. Den ökade användningen av polymera fiberkompositer medför ett ökatbehov av rationella produktionsmetoder. Inom flygindustrin tillverkas ofta polymera kolfiberkompositprodukter av så kallatprepreg-material som består av kolfibrer impregnerade med en plast. Det finns tvåhuvudalternativ för automatisk tillverkning av prepreg-baserade produkter, automatisktejpläggning eller automatisk fiberplacering. De två alternativen har tekniskabegränsningar och är förknippade med mycket höga investeringskostnader vilket gör attdet finns produkter som de inte kan tillverka eller som inte är kostnadseffektiva atttillverka med dessa två metoder. Andra automatiska alternativ har utvecklats, men har intenått någon större industriell implementering. Bristen på automatiseradetillverkningsalternativ leder till att produkter med komplex form, och som tillverkas i småoch medelstora volymer ofta tillverkas manuellt. Forskningen som presenteras i denna avhandling syftar till att undersöka hur automatiskatillverkningsceller för tillverkning av polymera kolfiberkompositprodukter med komplexform kan utformas så att de uppfyller de krav som gäller för tillverkningen av produkterför flygindustrin och är lämpliga för låga och medelhöga tillverkningsvolymer. Endemonstratorcentrerad forskningsmetod har använt för att utforska området och ett flertaldemonstratorer har byggts och testats tillsammans med partners från industrin och andraforskningsorganisationer. Demonstratorerna, som är kompletta tillverkningsceller, haranvänts för att identifiera metoder och utrustning som är nödvändiga att utveckla för attautomatisera denna typ av tillverkning och för att undersöka några metoder och tillhörandeutrustning mer i detalj. Demonstratorerna har också använts för att kartlägga faktorer sompåverkar hur metoder och utrustning utformas. Automatisk tillverkning av produkter med komplex form kan förenklas genom att delaupp tillverkningen i två steg. Först läggs prepreg-ark ihop till ett laminat som formas tillproduktens form i ett efterföljande steg. För att automatisera denna typ av tillverkningbehöver nyckelmetoder och nyckelutrustning för hopläggning av laminat, borttagning avskyddspapper samt formning av laminat till komplexa former utvecklas. Viktiga faktorersom påverkar utformningen av tillverkningscellerna är prepreg-materialens låga styvhetoch klibbiga yta, de höga kvalitetskrav som gäller för tillverkning avflygplanskomponenter samt att systemen måste hantera en stor mängd olikformadeprepreg-ark. Demonstratorerna visar att det är möjligt att automatisera tillverkningen avpolymera kolfiberprodukter med komplex form genom automatisk uppläggning ochformning av plana laminat. Tester med demonstratorerna pekar på att det är möjligt atttillverka produkterna i enlighet med de kvalitetskrav som finns för manuell tillverkningav liknande produkter.

MATS Satellite

Sportbilsbranchen har utvecklats i flera decennier och det råder en konstant efterfrågan för nya idéer och teknologier som kan förbättra sportbilar. Detta stämmer framförallt in inom superbilsbranchen, där det är en stor konkurrens mellan företag om vem som först utvecklar nya teknologier som gör deras bilar till de attraktivaste på marknaden.   Ett område inom fordonsutvecklingen är aerodynamik och dess användning för att förbättra fordons prestanda vid körning i raksträckor och i kurvor. Sportbilstillverkarnas mål är oftast att utveckla fordon till att accelerera snabbt, nå en hög topphastighet, kort bromssträcka samt att nå så hög hastighet som möjligt i kurvor utan att glida av vägen. Det finns flera metoder för att uppnå detta, men det sätt som behandlas i denna rapport är anvädningen av bakvingar.   Bakvingar förekommer i flera konfigurationer och modifikationer för att uppfylla användarens önskemål och krav. De vingkonfigurationer som behandlas i detta projekt är single- och multi-elementa vingar. Single-elementa vingar kännetecknas av att de består av en enkel vingarea. Fördelen med dessa konfigurationer är att de producerar låga luftmotstånd vid låga anfallsvinklar, vilket bland annat gör dem optimala för höga hastigheter. Multi-elementa vingar består av två eller fler vingareor. I och med detta kan en större negativ lyftkraft uppnås vilket gör dem optimala vid svängning. Multi-elementa vingar kan även användas vid högre anfallsvinklar med en minskad risk att turbulens uppstår.   Syftet i detta projekt var att ge en teoretisk analys av vad som kan uppnås om en single- och multi-element vinge kombineras i en och samma konfiguration. Tanken är att i praktiken har denna kombinerade vingkonfiguration en klaff som kan fällas ut för att kunna utnyttja båda vingkonfigurationernas fördelar och på så sätt förbättra sportbilars acceleration, topphastighet, bromsningsförmåga samt svängningshastighet.   Metoden bestod av att använda teoretiska beräkningar och analyser för att nå slutsatser om en sådan typ av vinge skulle vara fördelaktig, eller om de existerande konfigurationerna är tillräckliga. Detta gjordes genom att använda en tidigare analys som undersökte kraftskillnaderna hos en single- och multi-element vinge med samma dimensioner. Med vingarnas data kunde beräkningar genomföras på ett typfordon, där resultaten av vingarnas påverkan på fordonets topphastighet, acceleration, bromsning och kurvkörning samlades in och jämfördes. Med dessa jämförelser kunde en slutsats dras om vilka vingkonfigurationer som visade bäst resultat vid de olika situationerna.     Resultatet visar att en vinge som är en kombination av single- och multi-element kan vara fördelaktig över existerande konfigurationer. I och med att den single-elementa vingen har lägst luftmotstånd så passar den bäst vid acceleration vid hög hastighet samt för att uppnå höga topphastigheter. Vid acceleration i låga farter är den multi-elementa vingen mer fördelaktiga på grund av dess högre negativa lyftkraft. Den multi-elementa vingen passar även bättre för kraftigare bromsningsverkan samt högre svängningshastigheter. / The sports car industry has been under constant development for decades and there is a large demand for new ideas and technologies that can improve sports cars. This is particularly true in the super car industry, where there is a constant competition between companies about who first develops new technologies that can make their cars the most attractive on the market.   One area of development is in aerodynamics and how it can be used to improve vehicle performance when driving on straights and in curves. Usually, the goal is to get the vehicle to accelerate faster, reach a high top speed, have a short braking distance and to have as high speed as possible in curves without slipping off the road. There are several methods to achieve this, but the way that is discussed in this report are the use of rear wings.   Rear wings exist in several configurations in order to reach the requests and requirements of the car manufacturer. The wing configurations addressed in this project are single and multi-element wings. Single-element wings are characterized by their single wing area. The advantage of these configurations is that they produce low resistance at low angles of attack, which among other things makes them optimal for high speeds. Multi-element wings consist of two or more wing areas. With this, a larger negative lifting force can be achieved, which makes them optimal for achieving high turning speeds. Multi-element wings can also be used at higher angles of attack without the risk of the wing stalling.   In this project, the goal is to provide a theoretical analysis of what can be achieved if a single and multi-element wing is combined into one and the same configuration. The idea is that in practice, this combined wing has a flap that can be folded in and out in order to be able to utilize the advantages of both wing configurations and thus improve a sports car's acceleration, top speed, braking ability and turning speed.   The method consisted of using theoretical calculations and analyses to reach conclusions as to whether such a type of wing would be advantageous, or if the existing configurations are good enough for what they are used for. This was done by using a previous analysis that examined the differences between a single and multi-element wing of the same dimensions. With the data from these wings, calculations could then be made on a theoretical car, where the results of the wings' influence on top speed, acceleration, braking and curve driving were collected and compared. With these comparisons, a conclusion could be made about which of the wings were best for the different scenarios.   The result shows that a wing with a combination of single and multi-elements can be advantageous. Since the single-element wing has the lowest drag, it fits best at top speeds. When accelerating at low speeds, multi-element wings are more advantageous because of their higher downforce. They also fit better for greater braking effect and higher turning speeds.

The present thesis deals with the analysis of Environmental Control System (ECS) as a part of the aircraft conceptual design. The research focuses on developing methods for modelling, simulation and optimization of current and future cooling technologies suitable for aircraft applications. The work started with a pre-study in order to establish the suitability of different cooling technologies for ECS application. Therefore, five technologies namely, Bootstrap (BS), Reverse-Bootstrap (RBS), vapour cycle system (VCS), magnetic cooling (MC) and thermo-electric cooling (EC), were assessed from a theoretical point of view by the method of benchmarking. This resulted into the selection of three most suitable technologies that were further modelled and simulated in Dymola. In order to compare the optimum designs for each technology, the models were optimized using the modeFRONTIER software. The comparison was performed based on the optimum ratio of maximum power of cooling and minimum fuel penalty. The results showed that VCS has the “best” performances compared to BS and RBS. In addition to the active technologies, passive cooling methods such as liquid cooling by means of jet-fuel and poly-alpha-olefin were considered to address high heat transfer rates. In order to apply the cooling technologies in the ECS, concept system architectures were formulated using the functional analysis. This led to the identification of basic functions, components and sub-systems interaction. Based on the comparison carried out previously and the functional analysis, two ECS architectures were developed. Design optimization procedure was applied further in order to assess each concept and also to study the differences between the two concept architectures. The results depict the complex interaction of different key parameters of the architectures and their influence on the outcome. The study culminated with a proposed methodology for formulation of systems architecture using information from the optimization results and a robust functional analysis method. To sum up, the thesis proposes a simulation-based optimization method that allows inclusion of ECS system in aircraft conceptual design phase. The study also proves the complexity of the conceptual design stage for ECS architectures which highly influences the design of the combat aircraft.

This Master's Thesis handles prestudy work and early hardware development that resulted in architectural definitions and prototype hardware of electronic ground support equipment. This equipment is destined to emulate the electric power consumption of the PPS5000 Hall Effect Thruster (HET), for use in satellite end-to-end tests of the all-electric Geostationary Satellite Electra, developed at OHB Sweden AB. The Thruster Emulator (TEM) was defined through a resulting compilation of intricate interdependent components that interface the satellite power system and the thruster, which yielded an architecture development to support some basic predefined emulator requirements. This architecture was then analyzed to form a base-line conceptual function of the emulator system, which incorporates the entire HET functionality. Six primary HET impedances were defined, of which the three most complex impedances were investigated fully. For the primary thruster discharge, research is shown of the complexity of implementing advanced electronic load hardware directly to the satellite's 5kW power system with respect to the transient primary plasma discharge during thruster start up, and with limitations on the electronic load reducing emulator-thruster similarities. Additionally, a fully functional plasma ignition emulator prototype circuit board was built to be used in the final hardware of the TEM to emulate the external HET cathode start-up functionality. Finally, a feasibility study for designing a possible solution for the large PPS5000 electromagnet impedance was performed, resulting in the manufacture of two prototype inductors with unsatisfying performance results according to the design requirements.

<p>Waves are a fundamental feature in many parts of physics, since they transport energy without transporting matter. This is the case also in space physics. Waves are responsible for energy transport both between different parts of space and between different particles in the space plasma. They are also useful for diagnostics of the space plasma itself. The present thesis considers two different parts of the large subject of space plasma waves: Lower hybrid cavities (LHCs) and simple-pole particle distribution functions.</p><p>The LHCs are localised density depletions that have been observed by several spacecraft. They have increased wave activity in the lower hybrid frequency range, and was previously found on altitudes up to 1750 km. New observations by the Viking and Cluster satellites show that they are common magnetospheric features, at least up to an altitude of 35,000 km. Theoretical results, assuming a cylindrically symmetric density depletion, show that even though the density depletion may decrease slowly with increasing radial distance, and thus be essentially infinite in extent, there is a maximum distance within which a trapped mode, with given wave number <i>k</i><i>z</i> parallel to the geomagnetic field, may propagate. Furthermore, there is a local relation between the plasma density gradient and the lowest possible frequency that the trapped waves can have, for any monotonic density and given <i>k</i><i>z</i>. The combined theoretical and observational results indicate that the length of the cavities is larger than the width by a factor of at least 200.</p><p>Simple-pole particle distribution functions are introduced because they can model high velocity tails of the particle distribution in a way that is not possible to do with Maxwellian distribution functions. These distributions also simplify the calculations. This gives new possibilities for the physical understanding, as well as the numerical calculations, of the dispersion relations of real space plasmas. The dispersion relations of plasmas described by simple-pole distributions are examined, both for unmagnetised and for magnetised plasmas. These examples show how particle populations with the same density and mean particle energy, but with somewhat different distribution functions, have different wave propagation properties that should be observable by existing spacecraft.</p>

<p>The Earth's bow shock is a boundary where the solar wind becomes decelerated from supersonic to subsonic speed before being deflected around the Earth. This thesis presents measurements by the Cluster spacecraft upstream and at the Earth's quasi-parallel bow shock where the angle between the upstream magnetic field and the bow shock normal is less than 45 degrees. An intrinsic feature of quasi-parallel shocks is the ability of ions, that are reflected off the shock in a specular manner, to propagate far upstream and to interact with the incident solar wind. This leads to the generation of a variety of plasma waves, e.g., Ultra-Low Frequency (ULF) waves, which in their turn interact with the different ion populations. Some of the ULF waves are thought to steepen into so-called Short Large-Amplitude Magnetic Structures (SLAMS). </p><p>This thesis studies the impact of SLAMS on the incident solar wind. SLAMS are thought to play an important role in terms of 1) returning shock-reflected ions back to the shock where they can eventually contribute to downstream thermalisation and 2) local pre-dissipation of the solar wind. </p><p>The first electric field measurements of SLAMS showed a strong electric field rotation over SLAMS in association with the rotation of the magnetic field. This often leads to a local change from quasi-parallel to quasi-perpendicular conditions. In addition, short-scale electric field features were observed, e.g., spiky electric field structures associated with the leading edge of SLAMS and solitary electric field structures on Debye length scales, which are suggested to represent ion phase space holes. </p><p>Using the abilitiy of the four Cluster satellites to obtain propagation vectors of SLAMS and the high-resolution electric field measurements, the electric potential over SLAMS was studied. These structures are associated with a significant potential on the order of a few hundred to thousand Volt. Comparing these findings with data from the ion spectrometer, it was found that the bulk flow is locally significantly decelerated and moderately deflected and heated. In addition, SLAMS reflect incident ions on both the leading and trailing edge. The flux of so-called gyrating ions show a clear maximum in association with SLAMS. This indicates that SLAMS indeed play an important role for pre-dissipation of the solar wind upstream of the shock.</p>

Waves are a fundamental feature in many parts of physics, since they transport energy without transporting matter. This is the case also in space physics. Waves are responsible for energy transport both between different parts of space and between different particles in the space plasma. They are also useful for diagnostics of the space plasma itself. The present thesis considers two different parts of the large subject of space plasma waves: Lower hybrid cavities (LHCs) and simple-pole particle distribution functions. The LHCs are localised density depletions that have been observed by several spacecraft. They have increased wave activity in the lower hybrid frequency range, and was previously found on altitudes up to 1750 km. New observations by the Viking and Cluster satellites show that they are common magnetospheric features, at least up to an altitude of 35,000 km. Theoretical results, assuming a cylindrically symmetric density depletion, show that even though the density depletion may decrease slowly with increasing radial distance, and thus be essentially infinite in extent, there is a maximum distance within which a trapped mode, with given wave number kz parallel to the geomagnetic field, may propagate. Furthermore, there is a local relation between the plasma density gradient and the lowest possible frequency that the trapped waves can have, for any monotonic density and given kz. The combined theoretical and observational results indicate that the length of the cavities is larger than the width by a factor of at least 200. Simple-pole particle distribution functions are introduced because they can model high velocity tails of the particle distribution in a way that is not possible to do with Maxwellian distribution functions. These distributions also simplify the calculations. This gives new possibilities for the physical understanding, as well as the numerical calculations, of the dispersion relations of real space plasmas. The dispersion relations of plasmas described by simple-pole distributions are examined, both for unmagnetised and for magnetised plasmas. These examples show how particle populations with the same density and mean particle energy, but with somewhat different distribution functions, have different wave propagation properties that should be observable by existing spacecraft.

The Earth's bow shock is a boundary where the solar wind becomes decelerated from supersonic to subsonic speed before being deflected around the Earth. This thesis presents measurements by the Cluster spacecraft upstream and at the Earth's quasi-parallel bow shock where the angle between the upstream magnetic field and the bow shock normal is less than 45 degrees. An intrinsic feature of quasi-parallel shocks is the ability of ions, that are reflected off the shock in a specular manner, to propagate far upstream and to interact with the incident solar wind. This leads to the generation of a variety of plasma waves, e.g., Ultra-Low Frequency (ULF) waves, which in their turn interact with the different ion populations. Some of the ULF waves are thought to steepen into so-called Short Large-Amplitude Magnetic Structures (SLAMS). This thesis studies the impact of SLAMS on the incident solar wind. SLAMS are thought to play an important role in terms of 1) returning shock-reflected ions back to the shock where they can eventually contribute to downstream thermalisation and 2) local pre-dissipation of the solar wind. The first electric field measurements of SLAMS showed a strong electric field rotation over SLAMS in association with the rotation of the magnetic field. This often leads to a local change from quasi-parallel to quasi-perpendicular conditions. In addition, short-scale electric field features were observed, e.g., spiky electric field structures associated with the leading edge of SLAMS and solitary electric field structures on Debye length scales, which are suggested to represent ion phase space holes. Using the abilitiy of the four Cluster satellites to obtain propagation vectors of SLAMS and the high-resolution electric field measurements, the electric potential over SLAMS was studied. These structures are associated with a significant potential on the order of a few hundred to thousand Volt. Comparing these findings with data from the ion spectrometer, it was found that the bulk flow is locally significantly decelerated and moderately deflected and heated. In addition, SLAMS reflect incident ions on both the leading and trailing edge. The flux of so-called gyrating ions show a clear maximum in association with SLAMS. This indicates that SLAMS indeed play an important role for pre-dissipation of the solar wind upstream of the shock.

The overall goal of the research presented in this thesis is to extend the physical understanding of the unsteady external aerodynamics associated with highly maneuverable delta-wing aircraft by using and developing novel, more efficient computational fluid dynamics (CFD) tools. More specific, the main purpose is to simulate and better understand the basic fluid phenomena, such as vortex breakdown, that limit the performance of delta-wing aircraft. The problem is approached by going from the most simple aircraft configuration - a pure delta wing - to more complex configurations. As the flow computations of delta wings at high angle of attack have a variety of unusual aspects that make accurate predictions challenging, best practices for the CFD codes used are developed and documented so as to raise their technology readiness level when applied to this class of flows. Initially, emphasis is put on subsonic steady-state CFD simulations of stand-alone delta wings to keep the phenomenon of vortex breakdown as clean as possible. For half-span models it is established that the essential characteristics of vortex breakdown are captured by a structured CFD code. The influence of viscosity on vortex breakdown is studied and numerical results for the aerodynamic coefficients, the surface pressure distribution and breakdown locations are compared to experimental data where possible. In a second step, structured grid generation issues, numerical aspects of the simulation of this nonlinear type of flow and the interaction of a forebody with a delta wing are explored. Then, on an increasing level of complexity, time-accurate numerical studies are performed to resolve the unsteady flow field over half and full-span, stationary delta wings at high angle of attack. Both Euler and Detached Eddy Simulations (DES) are performed to predict the streamwise oscillations of the vortex breakdown location about some mean position, asymmetry in the breakdown location due to the interaction between the left and right vortices, as well as the rotation of the spiral structure downstream of breakdown in a time-accurate manner. The computed flow-field solutions are visualized and analyzed in a virtual-reality environment. Ultimately, steady-state and time-dependent simulations of a full-scale fighter-type aircraft configuration in steady flight are performed using the advanced turbulence models and the detached-eddy simulation capability of an edge-based, unstructured flow solver. The computed results are compared to flight-test data. The thesis also addresses algorithmic efficiency and presents a novel implicit-explicit algorithm, the Recursive Projection Method (RPM), for computations of both steady and unsteady flows. It is demonstrated that RPM can accelerate such computations by up to 2.5 times. / QC 20101019