Дисертації з теми "Aircraft protection"

Carefree handling refers to the ability of a pilot to operate an aircraft without the need to continuously monitor aircraft operating limits. At the heart of all carefree handling or maneuvering systems, also referred to as envelope protection systems, are algorithms and methods for predicting future limit violations. Recently, envelope protection methods that have gained more acceptance, translate limit proximity information to its equivalent in the control channel. Envelope protection algorithms either use very small prediction horizon or are static methods with no capability to adapt to changes in system configurations. Adaptive approaches maximizing prediction horizon such as dynamic trim, are only applicable to steady-state-response critical limit parameters. In this thesis, a new adaptive envelope protection method is developed that is applicable to steady-state and transient response critical limit parameters. The approach is based upon devising the most aggressive optimal control profile to the limit boundary and using it to compute control limits. Pilot-in-the-loop evaluations of the proposed approach are conducted at the Georgia Tech Carefree Maneuver lab for transient longitudinal hub moment limit protection. Carefree maneuvering is the dual of carefree handling in the realm of autonomous Uninhabited Aerial Vehicles (UAVs). Designing a flight control system to fully and effectively utilize the operational flight envelope is very difficult. With the increasing role and demands for extreme maneuverability there is a need for developing envelope protection methods for autonomous UAVs. In this thesis, a full-authority automatic envelope protection method is proposed for limit protection in UAVs. The approach uses adaptive estimate of limit parameter dynamics and finite-time horizon predictions to detect impending limit boundary violations. Limit violations are prevented by treating the limit boundary as an obstacle and by correcting nominal control/command inputs to track a limit parameter safe-response profile near the limit boundary. The method is evaluated using software-in-the-loop and flight evaluations on the Georgia Tech unmanned rotorcraft platform- GTMax. The thesis also develops and evaluates an extension for calculating control margins based on restricting limit parameter response aggressiveness near the limit boundary.

Carbon/Carbon (C/C) composite is defined as a carbon fiber reinforced carbon matrix. Since 1958 research has been carried out on the C/C composites. The main reason for the development of new C/C composites is the number of advantages it has to offer when compared with the regular materials. The areas where C/C composites are being used extensively are aerospace, military, etc. These C/C composites have better physical, mechanical, thermal properties when compared to steel. That is the reason C/C brakes made a huge impact in the aerospace industry. The main drawback associated with the C/C brakes which are used in aerospace applications is the oxidation of the composite at higher temperatures. Also other problem linked with the C/C brake is the migration of the inhibitors on to the friction surface of the brake which can eventually decrease the friction coefficient of the brake material. So, characterizing the commercially available Anti-Oxidant(A/O) system, developing a new A/O system which can not only provide better oxidation protection, but also an improved anti-oxidant migration resistance will be our main goal of this project.

The more-electric aircraft (MEA) concept is widely viewed as the next evolutionary step towards enabling the industry goal of developing optimised, fuel efficient aircraft. MEA have an increased dependency on electrical energy for distribution to secondary systems and, in order to service this increased dependence, the electrical power systems (EPS) are more complex with increased voltage distribution levels, power conversion stages and safety critical components compared with their conventional counterparts. These complexities will only increase in future platforms as they further embrace the MEA concept - the migration to increasingly novel, critical and complex EPS will incur several development and integration challenges. This thesis considers the fundamental challenge of maintaining high reliability standards within future aircraft EPS through the development of accurate and discriminative real-time protection systems which will react during fault conditions. Specifically, the thesis researches novel methods that improve real-time aircraft EPS protection and health management systems by 1) accurately diagnosing degraded faults before their progression to critical failure and 2) diagnosing faults that are difficult to detect using only conventional protection methods – in particular, series arc faults are considered. Within future aircraft EPS, the volume of operational data is expected to significantly increase beyond that of the conventional systems; consequently, the thesis focuses on the use of data-driven, machine learning based methods, to enable these extended functionalities of the EPS protection and health management systems. The types of machine learning modelling techniques that were chosen are explained and justified. Conventional protection methods are described, including a discussion on the difficulties in using them to detect both degraded fault modes and arcing conditions. The necessity to detect these types of faults in an accurate and timely manner is also discussed. One of the main contributions of the thesis is the proposal of the EPSmart method that can autonomously diagnose and isolate a multitude of degraded faults within an aircraft representative EPS. These degraded faults include intermittent and incipient conditions, which, in comparison to overcurrent faults, often lack the energy to be detected by conventional means. Early, and accurate, detection of these conditions will improve overall system health management and reliability and ensure safe operation of the aircraft. Further contribution is the design of the IntelArc method that can detect series arc faults within direct current supplied systems. Accurate detection of series arc faults is extremely challenging as, despite their presence being a serious fire hazard, they result in a decrease of load current. Although methods do exist for diagnosis of series arcing, there remain challenges with regards to accurate detection across different system configurations and operating conditions. The thesis shows the potential for IntelArc to provide accurate detection across a variety of configurations and operating conditions. While the thesis only describes the initial development of these novel methods, the significant conclusions are that application testing has shown the potential for them to enhance real-time network protection, fault tolerance and health management of aircraft EPS through detection of degraded fault and arcing conditions.

This body of work examines the process involved in researching a mobile explosive containment unit for use on board a commercial aircraft. If a device with unknown origin were discovered on board a commercial aircraft an explosive containment unit could be used to dispose of it thereby preventing the passengers and the hardware from incurring any harm. A methodology was developed to help understand and effectively capture the properties of nominal explosives, the detonation pulse, ensuing shock and pressure waves. This methodology was developed with the purpose of mitigating these explosive effects. The information concerning the material properties, shape and sizes of an explosive containment unit were all analyzed to identify one optimal containment unit. This containment unit was utilized extensively in modeling to determine a range of possible materials and reinforcement methods, for reducing the total weight of the unit. Upon optimizing the containment unit numerical analysis was performed on a fuselage section of a narrow body commercial aircraft with the containment unit. The containment unit was successful in arresting the explosion before it was able to cause harm to its surroundings. The success of these containment units proves that the methodology discussed and developed here is capable of rabidly developing and analyzing explosive containment units to fit a wide variety of needs.
Master of Science

Magnesium alloys exhibit desirable properties for use in transportation technology. In particular, the low density and high specific strength of these alloys is of interest to the aerospace community. However, the concerns of flammability and susceptibility to corrosion have limited the use of magnesium alloys within the aircraft cabin. This work studies a magnesium alloy containing rare earth elements designed to increase resistance to ignition while lowering rate of corrosion. The microstructure of the alloy was documented using scanning electron microscopy. Specimens underwent salt spray testing and the corrosion products were examined using energy dispersive spectroscopy.

Much research of Anti-Oxidant has been developed and is still being developed to protect Carbon-Carbon(C/C) material from oxidizing. C/C materials tend to lose their mechanical properties due to the oxidation. The aerospace brake industries have conducted a lot of research on this, because C/C material is an excellent material to be used for brake systems if a good oxygen protection is developed for it. The research performed by Dr.Jarlen Don detected a problem with the oxidation at high temperatures with the current composition. Phosphorus based coating does not protect C/C for more than 15 hours at 871C. By doing a multi-layer coating of the anti-oxidant, the anti-oxidant will be able to protect the brake systems better at a high temperature. To address the problem, research and experiments were conducted to protect oxidation at higher temperatures by using a silicon-based anti-oxidant. Silicon based overcoat will be the top layer of the anti-oxidant while the bottom will be the phosphorus based anti-oxidant that previously has been coated.

Thesis (M.S. in Operations Research)--Naval Postgraduate School, June 2009.
Thesis Advisor(s): Horne, Gary E. "June 2009." Description based on title screen as viewed on July 13, 2009. Author(s) subject terms: border security, border protection, border patrol, unmanned aerial system (UAS), UAV, MANA, Nearly-Orthogonal Latin Hypercube, regression tree, linear regression. Includes bibliographical references (p. 89-93). Also available in print.

Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Prasad, JVR; Committee Member: Costello, Mark; Committee Member: Johnson, Eric; Committee Member: Schrage, Daniel; Committee Member: Vela, Patricio. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Purpose - This master thesis evaluates the hybrid-electric aircraft project E-Fan X with respect to its economical and environmental performance in comparison to its reference aircraft, the BAe 146-100. The E-Fan X is replacing one of the four jet engines of the reference aircraft by an electric motor and a fan. A turboshaft engine in the cargo compartment drives a generator to power the electric motor. --- Methodology - The evaluation of this project is based on standard aircraft design equations. Economics are based on Direct Operating Costs (DOC), which are calculated with the method of the Association of European Airlines (AEA) from 1989, inflated to 2019 values. Environmental impact is assessed based on local air quality (NOx, Ozone and Particulate Matter), climate impact (CO2, NOx, Aircraft-Induced Cloudiness known as AIC) and noise pollution estimated with fundamental acoustic equations. --- Findings - The battery on board the E-Fan X it is not necessary. In order to improve the proposed design, the battery was eliminated. Nevertheless, due to additional parts required in the new configuration, the aircraft is 902 kg heavier. The turboshaft engine saves only 59 kg of fuel. The additional mass has to be compensated by a payload reduced by 9 passengers. The DOC per seat-mile are up by more than 10% and equivalent CO2 per seat-mile are more than 16% up in the new aircraft. --- Research limitations - Results are limited in accuracy by the underlying standard aircraft design calculations. The results are also limited in accuracy by the lack of knowledge of some data of the project. --- Practical implications - The report contributes arguments to the discussion about electric flight. --- Social implications - Results show that unconditional praise given to the environmental characteristics of this industry project are not justified.

Purpose - Find optimal flight and design parameters for three objectives: minimum fuel consumption, Direct Operating Costs (DOC), and environmental impact of a passenger jet aircraft. --- Approach - Combining multiple models (this includes aerodynamics, specific fuel consumption, DOC, and equivalent CO2 mass) into one generic model. In this combined model, each objective's importance is determined by a weighting factor. Additionally, the possibility of further optimizing this model by altering an aircraft's wing loading is analyzed. --- Research limitations - Most models use estimating equations based on first principles and statistical data. --- Practical implications - The optimal cruise altitude and speed for a specific objective can be approximated for any passenger jet aircraft. --- Social implications - By using a simple approach, the discussion of optimizing aircraft opens up to a level where everyone can participate. --- Value - To find a general answer on how to optimize aviation, operational and design-wise, by using a simple approach.

Purpose - This thesis presents a comparison of aircraft design concepts to identify the superior propulsion system model among turbo-hydraulic, turbo-electric and classic jet propulsion with respect to Direct Operating Costs (DOC), environmental impact and fuel burn. --- Approach - A simple aircraft model was designed based on the Top-Level Aircraft Requirements of the Airbus A320 passenger aircraft, and novel engine concepts were integrated to establish new models. Numerous types of propulsion system configurations were created by varying the type of gas turbine engine and number of propulsors. --- Findings - After an elaborate comparison of the aforementioned concepts, the all turbo-hydraulic propulsion system is found to be superior to the all turbo-electric propulsion system. A new propulsion system concept was developed by combining the thrust of a turbofan engine and utilizing the power produced by the turbo-hydraulic propulsion system that is delivered via propellers. The new partial turbo-hydraulic propulsion concept in which 20% of the total cruise power is coming from the (hydraulic driven) propellers is even more efficient than an all turbo-hydraulic concept in terms of DOC, environmental impact and fuel burn. --- Research Limitations - The aircraft were modelled with a spreadsheet based on handbook methods and relevant statistics. The investigation was done only for one type of reference aircraft and one route. A detailed analysis with a greater number of reference aircraft and types of routes could lead to other results. --- Practical Implications - With the provided spreadsheet, the DOC and environmental impact can be approximated for any commercial reference aircraft combined with the aforementioned propulsion system concepts. --- Social Implications - Based on the results of this thesis, the public will be able to discuss the demerits of otherwise highly lauded electric propulsion concepts. --- Value - To evaluate the viability of the hydraulic propulsion systems for passenger aircraft using simple mass models and aircraft design concept.

Aviation industry is continuously growing especially for very long distance flights due to the globalisation of local economies around the world and the explosive economic growth in Asia. Reducing the time of intercontinental flights from 16-20 hours to 4 hours or less would therefore make the, already booming, ultra-long distance aviation sector even more attractive. To accomplish this drastic travel time reduction for civil transport, hypersonic cruise aircraft are considered as a potential cost-effective solution. Such vehicles should also be fuelled by liquid hydrogen, which is identified as the only viable propellant to achieve antipodal hypersonic flight with low environmental impact. Despite considerable research on hypersonic aircraft and hydrogen fuel, several major challenges should still be addressed before such airliner becomes reality. The current thesis is therefore motivated by the potential benefit of hydrogen-fuelled hypersonic cruise vehicles associated with their limited state-of-the-art. Hypersonic cruise aircraft require innovative structural configurations and thermal management solutions due to the extremely harsh flight environment, while the uncommon physical properties of liquid hydrogen, combined with high and long-term heat fluxes, introduce complex design and technological storage issues. Achieving hypersonic cruise vehicles is also complicated by the multidisciplinary nature of their design. In the scope of the present research, appropriate methodologies are developed to assess, design and optimize the thermo-structural model and the cryogenic fuel tanks of long-range hydrogen-fuelled hypersonic civil aircraft. Two notional vehicles, cruising at Mach 5 and Mach 8, are then investigated with the implemented methodologies. The design analysis of light yet highly insulated liquid hydrogen tanks for hypersonic cruise vehicles indicates an optimal gravimetric efficiency of 70-75% depending on insulation system, tank wall material, tank diameter, and flight profile. A combination of foam and load-bearing aerogel blanket leads to the lightest cryogenic tank for both the Mach 5 and the Mach 8 aircraft. If the aerogel blanket cannot be strengthened sufficiently so that it can bear the full load, then a combination of foam and fibrous insulation materials gives the best solution for both vehicles. The aero-thermal and structural design analysis of the Mach 5 cruiser shows that the lightest hot-structure is a titanium alloy construction made of honeycomb sandwich panels. This concept leads to a wing-body weight of 143.9 t, of which 36% accounts for the wing, 32% for the fuselage, and 32% for the cryogenic tanks. As expected, hypersonic thermal loads lead to important weight penalties (of more than 35 %). The design of the insulated cold structure, however, demonstrates that the long-term high-speed flight of the airliner requires a substantial thermal protection system, such that the best configuration (obtained by load-bearing aerogel blanket) leads to a titanium cold design of only 4% lighter than the hot structure. Using aluminium 7075 rather than titanium offers a further weight saving of about 2 %, resulting in a 135.4 t wing-body weight (with a contribution of 23 %, 25 %, 18%and 34%from the TPS, the wing, the fuselage, and the cryogenic tanks respectively). Given the design hypotheses, the difference in weight is not significant enough to make a decisive choice between hot and cold concepts. This requires the current methodologies to be further elaborated by relaxing the simplifications. Investigation of the thermal protection must be extended from one single point to different regions of the vehicle, and the TPS thickness and weight should be considered in the structural sizing of the cold design. More generally, the design process should be matured by including additional (static, dynamic and transient) loads, special structural concepts, multi-material configurations and other parameters such as cost and safety aspects.

The thesis illustrates the efforts made to proof how water repellent surfaces can help reducing ice accretion in icing conditions: tests performed in an icing wind tunnel showed that application of superhydrophobic coatings allow considerable savings in supplied heating power, necessary to keep an aerodynamic wing clean from ice, and reduce runback ice, which often forms in unprotected areas. The present thesis is the result of a three year research study, aimed at understanding the potential of superhydrophobicity for combating icing accretion on aircrafts. The project was performed in the framework of a collaboration between University of Bergamo, University of Alberta and Alenia Aermacchi, an Italian aeronautic company. A considerable part of the work has been devoted to understanding the dynamic interaction between the liquid and the solid surface through single drop impact experiments. Performing drop impact studies allowed explaining the role of different parameters, e.g. impact Weber number and surface wettability, during drop impact on a solid surface and identifying the mechanisms that promote water shedding from the surface. Water drop impact tests performed in isothermal conditions allowed to understand in which conditions surface wettability has an effect on drop dynamics, and also to evaluate characteristic times related to drop impact (e.g. spreading time and rebound time). Water drop impact in freezing conditions, i.e. on surfaces below 0°C, showed that surface temperature does not affect drop dynamics, unless frost is present on the surface.

Aviation industry is continuously growing especially for very long distance flights due to the globalisation of local economies around the world and the explosive economic growth in Asia. Reducing the time of intercontinental flights from 16-20 hours to 4 hours or less would therefore make the, already booming, ultra-long distance aviation sector even more attractive. To accomplish this drastic travel time reduction for civil transport, hypersonic cruise aircraft are considered as a potential cost-effective solution. Such vehicles should also be fuelled by liquid hydrogen, which is identified as the only viable propellant to achieve antipodal hypersonic flight with low environmental impact. Despite considerable research on hypersonic aircraft and hydrogen fuel, several major challenges should still be addressed before such airliner becomes reality. The current thesis is therefore motivated by the potential benefit of hydrogen-fuelled hypersonic cruise vehicles associated with their limited state-of-the-art.Hypersonic cruise aircraft require innovative structural configurations and thermal management solutions due to the extremely harsh flight environment, while the uncommon physical properties of liquid hydrogen, combined with high and long-term heat fluxes, introduce complex design and technological storage issues. Achieving hypersonic cruise vehicles is also complicated by the multidisciplinary nature of their design. In the scope of the present research, appropriate methodologies are developed to assess, design and optimize the thermo-structural model and the cryogenic fuel tanks of long-range hydrogen-fuelled hypersonic civil aircraft. Two notional vehicles, cruising at Mach 5 and Mach 8, are then investigated with the implemented methodologies. The design analysis of light yet highly insulated liquid hydrogen tanks for hypersonic cruise vehicles indicates an optimal gravimetric efficiency of 70-75% depending on insulation system, tank wall material, tank diameter, and flight profile. A combination of foam and load-bearing aerogel blanket leads to the lightest cryogenic tank for both the Mach 5 and the Mach 8 aircraft. If the aerogel blanket cannot be strengthened sufficiently so that it can bear the full load, then a combination of foam and fibrous insulation materials gives the best solution for both vehicles. The aero-thermal and structural design analysis of the Mach 5 cruiser shows that the lightest hot-structure is a titanium alloy construction made of honeycomb sandwich panels. This concept leads to a wing-body weight of 143.9 t, of which 36% accounts for the wing, 32% for the fuselage, and 32% for the cryogenic tanks. As expected, hypersonic thermal loads lead to important weight penalties (of more than 35%). The design of the insulated cold structure, however, demonstrates that the long-term high-speed flight of the airliner requires a substantial thermal protection system, such that the best configuration (obtained by load-bearing aerogel blanket) leads to a titanium cold design of only 4% lighter than the hot structure. Using aluminium 7075 rather than titanium offers a further weight saving of about 2%, resulting in a 135.4 t wing-body weight (with a contribution of 23%, 25%, 18% and 34% from the TPS, the wing, the fuselage, and the cryogenic tanks respectively). Given the design hypotheses, the difference in weight is not significant enough to make a decisive choice between hot and cold concepts. This requires the current methodologies to be further elaborated by relaxing the simplifications. Investigation of the thermal protection must be extended from one single point to different regions of the vehicle, and the TPS thickness and weight should be considered in the structural sizing of the cold design. More generally, the design process should be matured by including additional (static, dynamic and transient) loads, special structural concepts, multi-material configurations and other parameters such as cost and safety aspects.
Doctorat en Sciences de l'ingénieur et technologie
This thesis was conducted in co-tutelle between University of Sydney and Université Libre de Bruxelles.Professor Dries Verstraete was my supervisor at the University of Sydney (so as a member of SydneyUni), but is automatically registered here as a member of ULB because he worked at ULB almost ten years ago.Ben Thornber is also a member of the University of Sydney but the application does not save it for an unknown reason.
info:eu-repo/semantics/nonPublished

2012 - 2013
Inspection and Maintenance are important aspects when considering the availability of aircraft for revenue flights. Modern airframe design is exploiting new exciting developments in materials and structures to construct ever more efficient air vehicle able to enable efficient maintenance. The improvement in the aircraft safety by advanced structures and protecting nanofillers is a revolutionary approach that should lead to the creation of novel generation of multifunctional aircraft materials with strongly desired properties and design flexibilities. In recent years, the development of new nanostructured materials has enabled an evolving shift from single purpose materials to multifunctional systems that can provide greater value than the base materials alone; these materials possess attributes beyond the basic strength and stiffness that typically drive the science and engineering of the material for structural systems. Structural materials can be designed to have integrated electrical, electromagnetic, flame resistance, and possibly other functionalities that work in synergy to provide advantages that reach beyond that of the sum of the individual capabilities. Materials of this kind have tremendous potential to impact future structural performance by reducing size, weight, cost, power consumption and complexity while improving efficiency, safety and versatility. It is a well-known fact that, actually, also a very advanced design of an aircraft has to take required inspection intervals into account. An aircraft with inherent protective abilities could help to significantly extend the inspection intervals, thereby increasing aircraft availability. The challenge in this research is to develop and apply a multifunctional composite for structural applications. The aim of this project is the formulation, preparation and characterization of structural thermosetting composites containing dispersed protective nanofillers. This project specifically targets composites tailored for multifunctional applications such as lightning strike protection, and flame resistance. These composites were designed to enable their application on next generation aircrafts. With regard to the objectives of this PhD project the multifunctional composite systems were developed with the aim of overcoming the following drawbacks of the composite materials: • reduced electrical conductivity; • poor flame resistance. The thermosetting material was projected considering compatibility criteria so that to integrate different functions into a material that is capable of bearing mechanical loads and serves as a structural material element. [edited by author]
XII n.s.

The thesis illustrates the efforts made to proof how water repellent surfaces can help reducing ice accretion in icing conditions: tests performed in an icing wind tunnel showed that application of superhydrophobic coatings allow considerable savings in supplied heating power, necessary to keep an aerodynamic wing clean from ice, and reduce runback ice, which often forms in unprotected areas. The present thesis is the result of a three year research study, aimed at understanding the potential of superhydrophobicity for combating icing accretion on aircrafts. The project was performed in the framework of a collaboration between University of Bergamo, University of Alberta and Alenia Aermacchi, an Italian aeronautic company. A considerable part of the work has been devoted to understanding the dynamic interaction between the liquid and the solid surface through single drop impact experiments. Performing drop impact studies allowed explaining the role of different parameters, e.g. impact Weber number and surface wettability, during drop impact on a solid surface and identifying the mechanisms that promote water shedding from the surface. Water drop impact tests performed in isothermal conditions allowed to understand in which conditions surface wettability has an effect on drop dynamics, and also to evaluate characteristic times related to drop impact (e.g. spreading time and rebound time). Water drop impact in freezing conditions, i.e. on surfaces below 0°C, showed that surface temperature does not affect drop dynamics, unless frost is present on the surface.

The thesis illustrates the efforts made to proof how water repellent surfaces can help reducing ice accretion in icing conditions: tests performed in an icing wind tunnel showed that application of superhydrophobic coatings allow considerable savings in supplied heating power, necessary to keep an aerodynamic wing clean from ice, and reduce runback ice, which often forms in unprotected areas. The present thesis is the result of a three year research study, aimed at understanding the potential of superhydrophobicity for combating icing accretion on aircrafts. The project was performed in the framework of a collaboration between University of Bergamo, University of Alberta and Alenia Aermacchi, an Italian aeronautic company. A considerable part of the work has been devoted to understanding the dynamic interaction between the liquid and the solid surface through single drop impact experiments. Performing drop impact studies allowed explaining the role of different parameters, e.g. impact Weber number and surface wettability, during drop impact on a solid surface and identifying the mechanisms that promote water shedding from the surface. Water drop impact tests performed in isothermal conditions allowed to understand in which conditions surface wettability has an effect on drop dynamics, and also to evaluate characteristic times related to drop impact (e.g. spreading time and rebound time). Water drop impact in freezing conditions, i.e. on surfaces below 0°C, showed that surface temperature does not affect drop dynamics, unless frost is present on the surface.

No presente trabalho foi implementado um modelo matemático para simular o sistema antigelo eletrotérmico de um aerofólio. Por meio do programa ONERA2D simulou-se o escoamento potencial completo com velocidade 44,7 m/s (100 mph) e 89,4 m/s (200 mph) em torno de um aerofólio perfil NACA0012 de corda 0,914 m (3 pés) com ângulo de ataque de 0°, e calculou-se a eficiência de coleta local de gotículas de água com diâmetro mediano volumétrico de 20 μm. Foram simuladas quatro condições de teste com diferentes distribuições de fluxo de calor nos aquecedores elétricos do sistema antigelo. O modelo previu a distribuição de temperaturas na superfície sólida do aerofólio e no filme de água líquida, e as distribuições de fluxo de água líquida sobre a superfície do aerofólio (\"runback water\") e de coeficiente de transferência de calor por convecção de calor entre a superfície do aerofólio e o escoamento gasoso. Os resultados da simulação obtidos com o modelo foram comparados com resultados experimentais da NASA e os resultados numéricos dos programas LEWICE/ANTICE (EUA) e CANICE (Canada). Para as regiões molhadas pelo filme de água líquida, obteve-se um desvio máximo de temperatura de 2,6°C entre os resultados do presente modelo e o resultados experimentais. Para as regiões secas, onde não existe o filme de água líquida sobre a superfície do aerofólio, obteve-se um desvio de máximo de temperatura de 8°C. As previsões para distribuição de vazão de \"runback\", posição do término do filme de água líquida foram comparadas com os resultados do programa LEWICE/ANTICE. O modelo desenvolvido simula com adequada aproximação os efeitos da transferência de calor e de massa por convecção entre a superfície não-isotérmica do aerofólio ou do filme de água líquida e o escoamento gasoso, bem como os efeitos da transição entre o escoamento laminar e o turbulento na camada limite dinâmica e térmica e ainda a influência do escoamento do filme de água líquida sobre o desempenho do sistema de antigelo do aerofólio.
An electro-thermal anti-ice system was simulated with a mathematical model developed in the present work. A 44.7 m/s (100 mph) and 89.4 m/s (200 mph) full potential flow around a 0.914 m (3 ft) chord NACA0012 airfoil with 0° angle of attack and the local water catch efficiency of 20 μm median volumetric diameter droplets impingement were calculated by the numerical code ONERA2D. Four test conditions were simulated with four different heat flux distributions of the anti-ice system according to the experimental work developed at NASA. The model predicted distributions of solid surface and liquid water film temperatures, runback water flow and convection heat transfer coefficient between airfoil or water surface and gaseous flow. The simulated results obtained by the mathematical model developed were compared to NASA experimental results and the ones predicted by the numerical codes LEWICE/ANTICE (US) and CANICE (Canada). For the regions wetted by the water film, the present model provided 2.6°C maximum temperature deviations between the predicted results and experimental data. For the dry regions, where there is no liquid water on the airfoil surface, an 8°C maximum temperature deviation was obtained. The runback flow and water film ending point position were compared to LEWICE/ANTICE numerical results. The developed model predicts adequately the convection heat and mass transfer effects between the non-isothermal airfoil or liquid water film surface and the gaseous flow, as well the effects of laminar to turbulent flow transition within dynamic and thermal boundary layer and the influence of the liquid water film flow on the anti-ice system performance.

Contrairement aux autres biens meubles, les navires, les aéronefs et les objets spatiaux affectés à la navigation internationale sont rattachés à un Etat. Le lien de droit public établi entre ces engins et l’Etat est communément appelé « nationalité ». Mais ce terme n’exprime pas à leur propos une institution à tous égards identique à la nationalité des personnes. Le rattachement examiné ne repose en effet pas sur des éléments de fait (naissance, ascendance etc.), mais uniquement sur un acte administratif interne, l’immatriculation. L’étude de la pratique, notamment des conventions internationales et des législations nationales, montre clairement que – contrairement à ce qu’on soutient souvent – il n’y a pas lieu de subordonner ce rattachement à un lien effectif. Ce qui importe, compte tenu notamment du fait que ces engins évoluent dans des espaces soustraits à toute compétence territoriale, est d’identifier l’Etat qui est seul compétent à l’égard de l’« ensemble organisé » formé par le véhicule, les personnes et la cargaison à bord, et qui est responsable de ses activités. Le droit international interdit dès lors la double immatriculation, mais il laisse aux Etats le pouvoir discrétionnaire de déterminer les conditions d’attribution de leur « nationalité », sans subordonner l’opposabilité internationale de celle-ci à quelque autre exigence que ce soit. Le danger est toutefois que cela favorise un certain laxisme de l’Etat d’immatriculation, ce qui exposerait au risque que des dommages graves soient causés aux personnes impliquées dans les activités de ces engins et – surtout – aux tiers. Mais ce sont les obligations internationales imposées et les droits corrélatifs reconnus dans le chef de l’Etat d’immatriculation qui sont déterminants à cet égard et non quelque mystérieuse « effectivité » du rattachement. Autrement dit, s’il n’est pas nécessaire d’imposer à l’Etat d’immatriculation des conditions internationales limitant sa liberté dans l’attribution de sa « nationalité » aux engins, il est indispensable d’exiger que celui-ci respecte ses obligations, c’est-à-dire exerce effectivement son contrôle et sa juridiction. Cette constatation se vérifie quel que soit l’engin en cause. Le rattachement créé par l’immatriculation constitue donc une institution "sui generis", commune aux navires, aéronefs et objets spatiaux et dont le régime juridique est encadré par le droit international
Unlike any other movable property, ships, aircraft and space objects that are engaged in international navigation are linked to a State. The legal connection established between these craft/vessels and the State is commonly referred to as “nationality”. However, in this case the term does not represent an institution identical in all respects to the nationality of persons. With regard to vessels, the legal connection to a State is not based on factual elements (such as birth, descent etc.), but merely on the internal administrative act of registration. The study of State practice, notably international conventions and national laws, clearly shows that – contrary to what is often argued – there is no need to make this connection dependent on a pre-existing effective link. What matters most, given that these craft navigate in international space beyond the territorial jurisdiction of sovereign States, is to identify the State that holds sole jurisdiction over said “organized entity” consisting of the vehicle, the persons and the cargo on board and that is responsible for its activities. Public international law therefore prohibits dual registration, but leaves States free to determine the conditions under which they will confer their “nationality”, without imposing any other requirement for the opposability of this legal bond to third States. The danger is that this situation encourages laxity on the part of the States of registry and therefore creates the potential for serious damage incurred by persons involved in these vessels’ activities and – mostly – by third persons. In this regard, it is the international obligations and corresponding rights of the States of registry which are critical, and not a mysterious “effectiveness” of the legal bond. In other words, it is not necessary to impose on the State of registry any international conditions which would limit its freedom with regard to the conferral of its “nationality” upon vessels. It is however indispensable to require that said State complies with its obligations, meaning that it has to effectively exercise its jurisdiction and control over those craft. This statement holds true regardless of the craft concerned. The legal bond created by the registration therefore constitutes a "sui generis" institution, common to ships, aircraft and space objects, and whose legal regime is governed by international law

Low Intensity Conflict (LIC) is a significant feature of the contemporary world and it is a particular challenge to the armed forces of many states which are involved is such conflict, or are likely to become so. This thesis is not concerned with how such difficult conflict situations arise. Rather it is concerned with how, from the point of view of the state, they may be contained and ultimately brought to a satisfactory resolution. The work is thus concerned with the practicalities of ending LIC. More specifically, the purpose of this research is to establish a framework of doctrinal and military principles applicable to the prevention and resolution of LIC. The principles of this thesis are based in numerous historical examples of LIC and six in depth case studies. These distilled principles are analysed in two central chapters, and are then applied in two latter defence force chapters so as to ensure there practicality and resilience. Numerous defence academics and military practitioners have been consulted in the production of this thesis; their contribution has further reinforced the functionality of the principles examined in this research. The research illustrates the criticality of a holistic approach to LIC. The function of this approach is to guarantee the stability of the sovereign state, by unifying civil, police, intelligence and military services. The effectiveness of the military elements must also be ensured, as military force is central to the suppression of LIC. Consequently, the research makes strategic and operational prescriptions, so as to improve the capability of defence forces that are concerned with preventing or resolving LIC.

碩士
嶺東科技大學
高階主管企管碩士在職專班
107
Our country National troops Army formed an army (the F-16. ghost along with the air force two generation of fighter planes in 1990 2000) the following closely army to introduce AH-64E in 2013 (Arab League handkerchief agreement attack helicopter) and in 2015 has introduced UH-60M (black hawk general helicopter), had the remarkable war strength promotion effect for our country national defense, and might carries Taiwan because of the outstanding material chain or the weapon to be possible to let commander provide in the battlefield resorts to arms the option, achieved conquers the enemy sends the victory the key aspect. But spreads the wings while the hard wing to hover the horizon, the rotor flies high the control battlefield, its behind must pay the material plans makes up and maintains the manpower, the usual general outside all is unable to understand and to know, all can have a slogan in the air force and in the army air base: “The air fight has the hero, a ground duty half merit”, may know the rear service maintenance is the hard wing and the rotor may spread the wings to control the battlefield the key, but under the Taiwan this subtropics special island climate environment, the corrosion protects and maintains this is the rear service maintenance troops overcomes the battlefield enemy diligently.

碩士
國立臺灣大學
土木工程學研究所
97
Aircraft shelters are the main targets for the enemy attacks at the airport during wartime. In order to reduce the damage to the aircrafts from the direct Air-Strike or indirect explosion debris；The construction of Hardened Aircraft Shelter （HAS）has already become the first priority of Air-Defense subjects for Taiwan. Most of the air bases at Taiwan are close by sea, without the protection by appropriate facility; the “Operational Readiness” of Avionics System will be suffered by the influences of temperature, humidity, salt, and acid rain...etc. Currently some of the bases have to operate the aircrafts on the apron, because of not having sufficient HASs, and tie-bar exposes, and debris shed off, from the roof of shelter. To ensure the Operational Readiness during shelf-life and survivability at war time, referring the newly designed HAS by USAF, and NATO, could be a good connect for reconstruction. This research is base on the following factors, such as storage environment, the probability of (none) direct hit during wartime, Destruction Mode, and Cost Effectiveness, of cost efficiency etc. The objects for analysis include the traditional RC HAS, hangar, underground tunnel, and the new steel arch shelter. Finally, consult and deliberate the efficiency and the protection strategy of the HAS around the world, and consider the finance status of country；compare with the investment, period of working days, and benefits, choose one of the best options.

Nesta dissertação analisa-se a utilização de Unmanned Aircraft Systems (UAS) Commercial off the shelf (COTS) em ações de combate/terrorismo, enumeram-se as suas vantagens e desvantagens e define-se a potencial ameaça que representam no âmbito da Harbour Protection (HP). Abordam-se os sistemas Counter-UAS (C-UAS), percebendo como atuam sobre os UAS; e recolhe-se doutrina C-UAS já em vigor em forças militares. Durante a realização desta dissertação foram efetuados testes reais com UAS e navios atracados na Base Naval de Lisboa, de modo a confirmar as capacidades dos sistemas atacantes e as reações a estes, e contribuiu-se para a elaboração das Táticas, Técnicas e Procedimentos (TTP) que estão a ser promulgadas na Marinha Portuguesa. O resultado desta dissertação é uma proposta de medidas a adotar para ajudar a contrariar a utilização de UAS COTS em ações ofensivas contra navios atracados ou fundeados e unidades, instalações e infraestruturas localizadas nos portos.
On this dissertation, the usage of Unmanned Aircraft Systems (UAS) Commercial off the shelf (COTS) in combat/terrorism actions is analysed, referring its advantages and disadvantages, and the potential threat posed by it to Harbour Protection is defined. It is studied what are Counter-UAS (C-UAS) systems, understanding how they work against UAS, and it is gathered information about C-UAS doctrine already in use by military forces. During this dissertation it had been executed real tests using UAS and warships moored at Lisbon Naval Base, in order to confirm the attacking systems’ capabilities and the reactions against them, and it had been given some contribution to the elaboration of Tactics, Techniques and Procedures (TTP) that are being promulgated on Portuguese Navy. This dissertation´s result is a proposal of some measures to be adopted in order to help to counteract the use of UAS COTS in offensive operations against moored or anchored ships and units, installations and infrastructures located in harbours.

Air transport plays a vital role in global economic growth and long-distance commutation. The aviation industry is found to double its fleet size every fifteen years. According to Air Transport Action Group (ATAG), 45 million aircraft took off worldwide in 2019, which translates to 1.5 lakh per day. Similar numbers are reported for other years under normal circumstances. Therefore, aviation appears to be an indispensable part of modern human civilization. Lightning is known to be one of the serious environmental threats to aircraft. Past incidents show that lightning strikes can lead to structural damage, operational interruption, and loss of lives. Field data suggest that, on average, an aircraft can get struck by lightning once or twice a year. Further, according to NOAA, The lightning strikes typically cost approximately two billion dollars to airline operators annually. Therefore, lightning protective measures are considered a crucial aspect of aircraft design. Design of suitable lightning protective measures involves Zoning of aircraft’s outer surface. Aircraft Zoning intends to differentiate lightning attachment points, channel slipping regions, and regions that carry just the stroke current. The first step in Zoning is to identify the initial attachment points. For the same, different methods like laboratory experiments, similarity principle, Rolling Sphere Method (RSM), and field-based approach are suggested in the standard, Aerospace Recommended Practice (ARP)-5414. Several aircraft accidents attributed to lightning strikes during the mid-20th century encouraged engineers to investigate the phenomena more closely. Therefore, several in-flight measurement campaigns were carried out in the late 80's, where the aircraft were flown inside the thunderstorm with the intention of getting struck by lightning. Field observation from these campaigns suggests two modes of lightning attachment, Aircraft-initiated and aircraft-intercepted. In the former one, under the influence of a thundercloud or descending lightning leader, the aircraft initiates bipolar leaders that lead to a strike. These leaders are deemed to propagate hundreds of meters to complete the lightning strike. In aircraft-intercepted strikes, the aircraft intercepts a descending lightning leader and hence gets struck. The methods suggested in the standard for identifying initial attachment points on aircraft are simple and have limitations. − The laboratory experiments on scaled aircraft models or isolated aircraft parts cannot portray all the aspects of discharges leading to the attachment. Therefore, the laboratory results cannot be directly extended to actual aircraft. − The similarity principle suggested in the standard is qualitative and can’t be extended to aircraft of any size and shape. − The field-based approach is not properly described in the standard, and hence, lacks clarity. − The 25 m Rolling Sphere Method (RSM) is routinely employed to determine the initial attachment points. Being a striking-distance-based approach, RSM only depicts the last stage of aircraft- intercepted attachment and, thus, doesn’t consider aircraft-initiated leaders. However, it is reported that 90% of the lightning strikes to aircraft are attributed to aircraft-initiated mode, which involves significant connecting leader activities. Therefore, precise assessment of initial attachment points requires considering the aircraft-initiated leader discharges. From the above discussion, it is evident that modeling bipolar leader discharges from aircraft is imperative in the context of lightning protection design. In literature, it is difficult to find a model for bipolar leader discharges from aircraft. However, works on either negative or positive leader discharge from energized electrodes in laboratory gaps and their extension to grounded objects are well-regarded in the literature. Knowledge from these works is found to be helpful to the present work. In spite of being responsible for most attachments, a model for bipolar leader discharges from aircraft is hard to find in the literature. Therefore, this work aims to develop a model for the inception and propagation of bipolar leaders from aircraft. Electrical discharges being field-driven phenomena, field computation is essential. Identifying the problem in hand as an open-geometry problem, a boundary-based method, Surface Charge Simulation Method (SCSM), is chosen for field computation. SCSM provides the global field distribution around the aircraft. Aircraft extremities are the most probable regions that can initiate discharges and, therefore, requires capturing the field around them in detail. The same is achieved by employing sub-modeling at the extremities. Sub-model charges are calculated using Charge Simulation Method (CSM), while the boundary condition on the sub-model is extracted from the global field solution. Modeling aircraft-initiated leader discharges involve modeling positive and negative leader discharges. Several models for positive and negative leader discharges in laboratory gaps are available in the literature. The latest model available in the literature for a positive leader discharge was developed by Becerra and Cooray. To reduce the computational burden, a simplified version of the model, which is also suggested by them, is considered in the present work. For negative leader discharge, a simplified physical model proposed by Z.Guo et al. is considered. Using the constructed model, the mechanism involved in the inception and propagation of the aircraft-initiated leader discharges is investigated and quantified. In contrast with discharges from energized electrodes or objects on the grounds, a few salient aspects of bipolar leader discharge from aircraft are pointed out. It is shown that aircraft potential changes with the development of connecting leaders, which modifies the field around it. As a consequence of the same, unipolar stable leader discharge from an aircraft is not viable. Therefore, the aircraft-initiated positive and negative leader discharges in a mutually supporting form are essential for the stable propagation of connecting leaders. The minimum ambient fields required for the stable propagation of bipolar leaders from a medium (DC-10) and a small aircraft (SDM) are determined. The values are well within the fields measured during different measurement campaigns. Subsequently, the dependency of this threshold field on permissible pitch and roll angle, aircraft flying altitude, and humidity are quantified. The aircraft-intercepted lightning strikes are also accounted for in this work. It is shown that, being electrically floating, the magnitude of aircraft potential increases, keeping the polarity the same as the descending leader tip potential. However, it is not the case for objects on the ground (i.e., buildings, towers, etc.). Therefore, the striking-distance-based approach, routinely employed for designing lightning protection for grounded objects, cannot be directly extended to aircraft. This also indicates a possible limitation of RSM while applied on aircraft. Further, The critical stroke current below which aircraft-intercepted mode of attachment is most probable is determined for two aircraft models, DC-10 and SDM. Unlike structures on the ground, the weight and volume of the lightning protection for aircraft should be constrained. Therefore, to provide adequate protection, it is absolutely essential to quantify the probability of lightning strikes to aircraft. Thus, based on the above model for lightning attachment, this work develops a methodology for estimating the rate of lightning strikes to aircraft. This method takes aircraft dimensions and spatial densities of lightning flashes and thunderstorms along its route as input. The proposed method is employed to estimate the average annual number of strikes to aircraft worldwide. Subsequently, the dependency of the strike rate on aircraft size and flying altitude are investigated. The entire exercise is carried out for medium-sized (DC-10) and small (SDM) aircraft. The estimated strike rates are well within the range of reported field data. Further, the estimated variation of strike rates with altitudes (below 3 km) correlates well with the data published by Boeing. The small deviations observed in the estimated strike rates are attributed to the assumption of cloud heights and takeoff/landing trajectory. Therefore, given exact data on thunderstorms, lightning flashes, and the operational behavior of an aircraft, the methodology can reliably estimate the rate of lightning strikes to aircraft. In summary, this work has developed a model for the inception and propagation of bipolar leaders from aircraft and also correctly picturizes the direct streamer mode of bridging involved in aircraft-intercepted attachment. The role of the air density (hence, altitude) is incorporated in the model, along with selected humidity values. The proposed model provides a discharge-physics-based method of identifying initial attachment points on aircraft. Therefore, the limitations of the methods suggested in the standard are overcome.The work has also developed a methodology for estimating the strike rate as a function of altitude, aircraft size, thunderstorms, and lightning flash density. The estimated strike rates correlate well with the reported data from field observation.

碩士
國立臺灣師範大學
衛生教育研究所
87
The purposes of this study are to establish a model for understanding satisfaction of residents and its relative factors about the protections of aircraft noise, and to give suggestions for administrative authorities. The sample elements are drawn from those households where located in the third and the second aircraft noise control areas of Taipei Song Shan airport and the second aircraft noise control area of Kaohsiung Hsiao Kang airport. By using simple random sampling, 300 samples were selected among each area. The data were collected via interview with the total 879 valid questionnaire. Frequency distribution, correlation, multiple regression, and path analysis are used in the data analysis. The major results of this study are as follows: 1. The residents were influenced severely by aircraft noise. 2. Most of the residents are unsatisfied with those protections, and misunderstand what those protections are, and have many needs of the protection. 3. Policy awareness and expectation directly influence residents'' satisfaction. The more awareness and less expectation, the more satisfaction. 4. The expectation of airport noise protection is influenced by cost-benefit assessment. People who have higher benefit perception, lower risk perception, and lower knowledge have lower policy expectation. 5. The knowledge of airport noise protection is influenced by benefit perception. The higher benefit perception, the more awareness of the protection policy. 6. The satisfaction of protections will be reflected on the political statement activity and residents'' moving. It is found that the satisfaction of noise control is the primary cause. 7. The cost-benefit assessment can influence the satisfaction indirectly. Risk perception is the most influential factor. 8. Demographic factors have significant but low influence on major variables. 9. The most important protection is policy of noise resource control because of a causal chain from noise resource to the political statement activity and residents'' moving. This causal chain includes noise resource influences risk perception, risk perception has major impact on expectation of protections, expectation has important influence on satisfaction of protections, and the satisfaction is the major reason of the political statement activity and residents'' moving. 10. The model is designed to explain the residents'' satisfaction of the protections on aircraft noise and fits well. To conclusion, follows are some suggestions for political authorities including: to effectively reduce the noise resources, to increase benefit perception, to communicate well with residents, to set the noise control areas properly, to soundproof the house, to do what residents need, to improve the quality of policy, and to give information about noise.

碩士
逢甲大學
工業工程與系統管理學研究所
97
Data Envelopment Analysis (DEA) is one of performance evaluation methods applying multiple inputs and multiple outputs from targeted decision making units (DMU). Traditional DEA models can only separate efficiency DMUs from non-efficiency DMUs. When one wants to completely rank DMUs or design alternatives, advanced DEA methods might be needed for this purpose. In addition to traditional DEA models, several advanced DEA models are needed for completely ranking design alternatives. The aircraft industry is technology-intensive, experience-intensive and capital-intensive. The aircraft engine accounts for about 30% of the total aircraft product value. The aircraft engine protection system is a key device to preventing aircrafts from malfunction. When designing the engine protection systems, the designer should consider many important factors such as reliability factor, cost factor, volume factor, weigh factor, and satisfactory factor. Using many combinations of design factors, the designer wants to know how to evaluate the best one among all design alternatives by DEA models. In this study, CCR model and BCC model are used to differentiate those efficiency and non-efficiency design alternatives. Then six advanced DEA models, including Andersen and Petersen model, Cross Efficiency model, Aggressive Cross Efficiency model, Benevolent Cross Efficiency model, Cross Reference model, and Common Weight, are analyzed and applied to completely rank those design alternatives. The study results suggest that Andersen and Petersen model and Cross Reference model give a consistent assessment result. On the other hand, Cross Efficiency model, Aggressive Cross Efficiency model and Benevolent Cross Efficiency model show a peculiar ranking result. Common Weight model can not provide a complete rank and need further investigation.