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Viewing 1 to 30 of 237
2013-09-17
Technical Paper
2013-01-2112
Vitaly Voloshin, Yong Chen, Rudolf Neydorf, Anna Boldyreva
This paper is dedicated to the study and improvement of the aerodynamic properties of the feeder airship in the context of MAAT project. FP7 MAAT project is based on the concept of two different types of airships (the cruiser and the feeder) working together as a transportation system. The current feeder concept includes unconventional shape changing envelope. Two problems are considered in this paper. The first problem is to find a condition of the effective vertical ascent for the feeder (from the ground to the altitude of the cruiser). A series of CFD simulations were carried out for the top flow for a range of altitudes from 0 to 16 km and velocities between 2 and 10 m/s. The results confirm the appearance of some negative effects, including high drag during the vertical ascent, especially, at low altitudes. The second problem is to study and reduce the side wind effects on the ascending feeder airship.
2013-09-17
Technical Paper
2013-01-2147
Joshua Smith, Duncan Kochhar-Lindgren
Precision hole inspection is often required for automated aircraft assembly. Direct contact measurement has been proven reliable and accurate for over 20 years in production applications. At the core of the hole measurement process tool are high precision optical encoders for measurement of diameter and countersink depth. Mechanical contact within the hole is via standard 2-point split ball tips, and diametric data is collected rapidly and continuously enabling the system to profile the inner surface at 0 and 90 degrees. Hole profile, countersink depth, and grip length data are collected in 6 seconds. Parallel to the active process, auto-calibration is performed to minimize environmental factors such as thermal expansion. Tip assemblies are selected and changed automatically. Optional features include concave countersink and panel position measurement.
2013-09-17
Technical Paper
2013-01-2076
Amir Massoudi
Multi-Layer Insulation (MLI) is the thermal insulation typically used in spacecraft or any other devices that are exposed to both extreme heat and cold. MLI blankets work to protect delicate internal and external applications from UV radiation, atomic oxygen, and mechanical stresses by using Teflon coated fiberglass cloth. The layers are usually made of a film made out of polyester or polyimide with vapor deposited layers of aluminum on one or both sides of the film to form reflector layers. These reflectors are separated by materials with low thermal conductivity. All the layers simply protect the system by preventing excessive heat loss from inner components and excessive heating from outer sources. Typically, MLI blankets are divided into a cover or outer layer, a reflector, a separator layer, an inner layer, and it has hardware installed to pass electrical charge from the surface of the blanket.
2013-09-17
Journal Article
2013-01-2184
Desire Guzman, Javier Camacho, Asuncion Rivero, Juan Ramon Astorga
Aerospace manufacturing requires efficient manufacturing processes. Composite materials are extensively used and manufacturing processes must evolve to overcome composite constraints for manufacturing and joining. Bolting is an extended joining process for composite materials in which a deformable blind bolt is stressed until joining forces are high enough to cause bolt breakage and ensure sufficient compression forces in the joint. Among bolting methods, blind bolting is an efficient composite joining method that enables the construction of aerospace composite structures accessing joints from a single side of the joint (front side), thus allowing for constructing closed structures where accessing the back side (blind side) is not possible. However, not being able to access the deformed head at the blind side prevents to perform a quality control and ensure a proper bolt deformation and a proper installation.
2013-09-17
Journal Article
2013-01-2151
Cosmos Krejci
Electroimpact's newest riveting machine features a track-style injector with Bomb Bay Ejection Doors. The Bomb Bay Ejection Doors are a robust way to eject fasteners from track style injector. Track style injectors are commonly used by Electroimpact and others in the industry. Using the Bomb Bay Doors for fastener ejection consists of opening the tracks allowing very solid clearing of an injector when ejecting a fastener translating to a more reliable fastener delivery system. Examples of when fastener ejection is needed are when a fastener is sent backwards, when there are two in the tube, or when a machine operator stops or resets the machine during a fastening cycle. This method allows fasteners to be cleared in nearly every situation when ejecting a fastener is required. Additional feature of Electroimpact's new injection system is integrated anvil tool change.
2013-09-17
Technical Paper
2013-01-2218
Dennis Michael Crowley, Carwyn Ward, Kevin Potter
Composite production rates will need to increase markedly to meet future demand, especially in the case of mainstream automotive. Coupled with that is need to keep quality levels high and costs down. Scrap represents a large portion of this cost and should be minimised. Due to the complexities of composite manufacture there are numerous sources of variation. These variations mean that a composite part cannot be considered to be “flawless”. Instead acceptable levels of variation are established. These requirements govern whether or not a part is scrapped based on a set of measurements. These measurements are carried out assuming that there are no flaws arising from the design of the part. This paper details the attempt to manufacture a flat panel followed by some more complex features in order to determine if the acceptance criteria can be rigidly adhered to.
2013-09-17
Technical Paper
2013-01-2222
Brian Tucker, Alan Love, Roger Caesley
Helicopter rotor systems are increasingly using flexible composite structures to provide the required control movement for the rotor blades. These structures such as rotor head flex beams can experience very high surface strains, which can be in the order of 15,000 με. This makes it difficult for them to be monitored using conventional surface bonded strain sensors. Helicopter rotor hubs incorporating thick composite flexures are subjected to delamination failures with correlate to bending excursions. Measurement of this deflection could be used to predict remaining useful life of the flexure and other hub components. Previous efforts to measure surface strains using fiber optic sensors led to mixed results and prompted an effort to explore embedded sensors. As part of a Vertical Lift Consortium project, the authors tested proof of concept manufacturing specimens to establish the ability of the sensors to survive the cure process in a closed cavity mold tool.
2013-09-17
Technical Paper
2013-01-2255
Jovan D. Boskovic, Joseph Jackson, Raman Mehra
In this paper we present results of a study of an integrated aero-propulsion flight control system. The resulting problem is that of controlling the system in which actuators operate on different time scales. This is a difficult problem since the control strategy needs to balance between not using the slow actuator at all, and slowing down the overall system to the time scale of the slow actuator. In the case of aero-propulsion control design for F/A-18 aircraft, the part of the control derivative matrix associated with engines is not full rank so not all states of interest can be simultaneously forced to track the commands. A control strategy that takes this constraint into account has been developed. The proposed IRAP approach is illustrated through simulation of F/A-18 aircraft dynamics under flight-critical control effector failures.
2013-09-17
Journal Article
2013-01-2330
Olivier Pahud, Didier Hoste
The composites development team at Bombardier Aerospace has pushed the Integrated Product Development Team to a new level. The team has been created outside the business priorities and was partially funded by a provincial government initiative to create a greener aircraft. A dedicated R&D team can reduce the gap between the different disciplines by encouraging them to work as one entity and rapidly develop high Technology Readiness Level (TRL) and high Manufacturing Readiness Level (MRL) solutions. Additionally, the interactions between the groups create a harmonization of the development philosophy and a sharing of the building block approach. This leads to a significant cost and lead time reduction in the coupon, element and detail testing. The constitution of the team also has a great impact on the level of expertise and the flexibility to adjust to new demands.
2013-09-17
Technical Paper
2013-01-2294
Faisal Khan, Ian Jennions, Tarapong Sreenuch
In today's aircraft the diagnostic and prognostic systems play a crucial part in aircraft safety while reducing the operating and maintenance costs. Aircraft are very complex in their design and require consistent monitoring of systems to establish the overall vehicle health status. Most diagnostic systems utilize advanced algorithms (e.g. Bayesian belief networks or neural networks) which usually operate at system or sub-system level. The sub-system reasoners collect the input from components and sensors to process the data and provide the diagnostic/detection results to the flight advisory unit. Several sources of information must be taken into account when assessing the vehicle health, to accurately identify the health state in real time. These sources of information are independent system-level diagnostics that do not exchange any information/data with the surrounding systems.
2013-09-17
Technical Paper
2013-01-2163
David Arriola, Aurelien Reysset, Marc Budinger, Frank Thielecke, Jean-Charles Mare
Recent trends towards lighter and more efficient commercial aircraft have motivated airframers to consider the use of electromechanical actuators EMA as the primary means of power for aircraft flight control systems. The transition from state-of-the-art hydraulic actuation to new electromechanical technologies poses a great challenge to both airframers and system suppliers for the correct and complete definition of new requirements. Transient effects such as electric motor overheating and inertial loads, previously not present or irrelevant for hydraulic actuators, now have to be taken into account. A knowledge-based environment containing design drivers for electromechanical components is combined with a validation method in order to aid the systems engineer to accomplish such task. This approach offers the potential to guarantee that all requirements are covered by a new technology, and that they are complete and consistent.
2013-09-17
Technical Paper
2013-01-2165
Alexandra Francois-Saint-Cyr, Boris Marovic, Weikun He
Electronic systems play a key role in the high reliability and safety of modern aircrafts. Components have become smaller and faster leading to an increase in power density and making thermal management a more vital part of the overall design. This paper will demonstrate how thermal transient testing combined with computational fluid dynamics (CFD) can help balance these design constraints and ensure that critical devices will work safely within their prescribed temperature limits. The first part of the paper will focus on the thermal characterization of a component using a continuous measurement method known as the static method per JEDEC51-1 standard. This data provides an insight of the overall component thermal performance and it can also be translated to structure function which helps with detecting potential internal thermal bottlenecks, such as a die attach material.
2013-09-17
Journal Article
2013-01-2169
Sonia L. Repetto, James F. Costello, Benjamin De Lacy Costello, Norman M. Ratcliffe, Joseph K.-W. Lam
Dissolved water is a normal component of jet fuel which is vapourised during combustion; however, free water is a contaminant that can starve engines, freeze to form ice crystals capable of blocking fuel feeds, support microbial growth, and contribute towards corrosion. Jet fuel may be protected from the potentially hazardous effects of free-water using biocides and icing/corrosion inhibitors. This investigation seeks to identify novel chemical approaches to the dual management of both water contamination and ice formation in jet fuel. The strategy of using organic molecules as dehydrating agents remains a relatively neglected approach perhaps because of the complexity of the physical organic chemistry involved in developing and refining these systems.
2013-09-17
Technical Paper
2013-01-2240
David W. Fogg, Weibo Chen, Rob Chambers
Refrigeration systems with parallel evaporators are prone to systemic instabilities and thermal excursions, particularly under variable loading conditions. Conventional vapor compression systems require evaporators to discharge at very high vapor qualities to prevent liquid ingress to the compressor. This requires active control algorithms to regulate the flow to individual evaporators. This paper introduces a novel liquid recirculation loop that minimizes the effects of flow maldistribution and prevents dryout using passive components. The loop utilizes a refrigerant phase separator, in conjunction with passive inlet restrictions, to mitigate flow maldistribution and support larger evaporator mass flow rates corresponding to low-to-moderate exit qualities. With greater margin in exit quality before dryout occurs, thermal excursions at the evaporator outlets are readily avoided.
2013-09-17
Technical Paper
2013-01-2244
Taewoo Kim, Sejong Oh, Kwanjung Yee
The purpose of this study is to investigate the effects of the size and location of wind fences on the rotor performance to avoid as well as quantify any adverse effects of outside wind on the measurement accuracy. To this end, firstly, a novel actuator disk method is developed which couples open source CFD code named OpenFOAM with blade element method and rotor flapping equations. Secondly, the parametric studies are conducted with respect to wind fence configurations which contain fence radius, inlet/outlet duct size and location etc. For quantitative evaluation of rotor performance variation according to inlet/outlet duct size, the mass flow and momentum rate on the ducts are. The rotor performance variation depending on the wind fence configuration is examined and consequently parametric study cases are classified according as calculated rotor thrust coefficient. Moreover, it is explained the difference of flow field in wind fence by demonstrating the pressure coefficient.
2013-09-17
Technical Paper
2013-01-2242
Andreas Himmler, Jace Allen, Vivek Moudgal
Hardware-in-the-loop (HIL) testing is an indispensable tool in the software development process for electronic control units (ECUs) and Logical Replaceable Units (LRUs) and is an integral part of the software validation process for many organizations. HIL simulation is regarded as the tried-and-tested method for function, component, integration and network tests for the entire system. Using the Model based design approach has further enabled improved and faster HIL implementations in recent years. This paper describes the changing requirements for HIL simulation, and how they need to be addressed by HIL technology. It also addresses the challenges faced while setting up a successful HIL system: namely the division of tasks, the total cost of ownership, budget constraints and tough competition and the adaptability of a HIL simulator to new demands. These requirements are discussed using a dSPACE HIL system architecture that was designed from the ground-up to address these needs.
2013-09-17
Journal Article
2013-01-2230
Thomas Wasselin, Stephane Richard, Fabrice Le Berr, Jean-Charles Dabadie, Guillaume Alix
Reducing greenhouse gas emissions to limit global warming is becoming one of the key issues of the 21st century. As a growing contributor to this phenomenon, the aeronautic transport sector has recently taken drastic measures to limit its impact on CO2 and pollutants, like the aviation industry entry in the European carbon market or the ACARE objectives. However the defined targets require major improvements in existing propulsion systems, especially on the gas generator itself. Regarding small power engines for business aviation, rotorcrafts or APU, the turboshaft is today a dominant technology, despite quite high specific fuel consumption. In this context, solutions based on Diesel Internal Combustion Engines (ICE), well known for their low specific fuel consumption, could be a relevant alternative way to meet the requirements of future legislations for low and medium power applications (under 1000kW).
2013-09-17
Journal Article
2013-01-2236
Rudolf Neydorf, Sergey Novikov, Roman Fedorenko
This paper is devoted to a method of creating of the automated ballonet system for pressure control inside an airship envelope. Along with the study of the effects of the positional control system parameters, the authors develop novel control scheme. It is based on a new hybrid controller, which combines positional approach to forming the output control signal with a contour of continuous correction of input signal, which defines the pressure drop on the surface of the envelope as a function of the flight altitude. This approach allows reducing the effect of self-oscillations of airship envelope internal pressure on the flight altitude. In order to prove the new approach the mathematical model is being obtained. The results of the derivation and simulations of the control system operation are presented in this paper.
2013-09-17
Journal Article
2013-01-2234
John C. Dalton, Roger Nicholson
We live in an era of increasing twin-engine commercial airplane operations, with large and very quiet high bypass ratio engines. At the same time, due to several decades of increased attention to the environment, we have large and increasing hazardous species bird populations. These trends, when combined, are not a prescription for continued assurance of a remarkable and enviable safety record for commercial aviation. Therefore, greater diligence must be placed on the evaluation of the current and future aviation wildlife hazard. We have some new weapons in this fight for greater capability to live with this situation. The basic problem is that different databases are populated independently from one another and often contain conflicting, contradictory, and erroneous data. Databases that were used individually, but not necessarily combined, are being utilized in a conjoined methodology to give us a better picture of the actual risk involved.
2013-09-17
Technical Paper
2013-01-2224
Joseph R. Malcomb
Previous Flex Track drilling systems move along two parallel tracks that conform to the contour of a work piece surface. Until recently, applications have been limited to relatively simple surfaces such as the cylindrical mid-body fuselage join of a commercial aircraft. Recent developments in the state of the art have introduced the 5-axis variant which is capable of precision drilling on complex contours. This paper presents solutions to two positioning challenges associated with this added functionality: the ability to align the spindle axis normal to an angled drilling surface while maintaining accuracy in tool-point position, the ability to maintain synced motion between dual drives on complex track profiles.
2013-09-17
Journal Article
2013-01-2228
David K. Winstanley
Honeywell has developed a unique turbofan engine for application to the super mid-size business aviation market, the HTF7000. This paper will describe the design of this engine including aeromechanical design of its components. The unique design features of this engine will be described along with the technology growth path to keep the engine current. This paper will also describe several features which have been developed for this engine in response to new regulatory requirements. Some aspects of the engine to aircraft integration will also be described.
2013-09-17
Journal Article
2013-01-2226
Abdelatif Atarsia
This technical paper deals with design and manufacture of axial and orbital cutters for drilling large diameters holes in Carbon Fiber Reinforced Plastics (CFRP) / Titanium (TA6V) thick stack by means of an Automated Drilling Unit fixed on a drilling template. Creating tools that drill such stacked holes in a single operation is particularly difficult. The common strategies for tool designs designated to cutting composites stacked with metals as titanium include uncoated carbide, tools with a diamond coating applied by chemical vapor deposition (CVD). It is also question of what kind of drilling process should we use to achieve larger holes in minimum time. Therefore, axial drilling process with pilot, drill and ream steps find a competitor drilling process named orbital drilling which can achieve both operations in one step allowing then, burrless, free delamination, small and easy removable chips all with one tool being able to achieve different hole sizes.
2013-09-17
Technical Paper
2013-01-2207
Michele Cencetti, Laura Mainini, Paolo Maggiore
A Multi-Objective Optimization (MOO) problem concerning the thermal control problem of Multifunctional Structures (MFSs) is here addressed. In particular the use of Multi-Objective algorithms from an optimization tool and Self-Organizing Maps (SOM) is proposed for the identification of the optimal topological distribution of the heating components for a multifunctional test panel, the Advanced Bread Board (ABB). MFSs are components that conduct many functions within a single piece of hardware, shading the clearly defined boundaries that identify traditional subsystems. Generally speaking, MFSs have already proved to be a disrupting technology, especially in aeronautics and space application fields. The case study exploited in this paper refers to a demonstrator breadboard called ABB. ABB belongs to a particular subset of an extensive family of MFS, that is, of thermo-structural panels with distributed electronics and a health monitoring network.
2013-09-17
Technical Paper
2013-01-2211
Julien Savard, Lin Bao, Guy Bois, Jean-François Boland
The Integrated Modular Avionics (IMA) architecture has been a crucial concern for the aerospace industry in developing more complex systems, while seeking to reduce space, weight and power (SWaP), as well as development, certification and production time. From a software perspective, that objective pushes developers to migrate toward safety critical space and time partitioning environment. However, mainstream commercial real-time operating systems (RTOS) offering such partitioning can be restrictive in early development due to very high licensing costs. That situation is even more striking when considering that low-cost alternatives could instead be used for system modeling and early simulation before acquisition of a target platform. This paper reviews existing low-cost and open-source development environments to propose a novel design flow. The proposed methodology starts with model-based analysis in the AADL modeling language.
2013-09-17
Technical Paper
2013-01-2283
Bejoy Sathyaraj, Priyasloka Arya
Structural coverage analysis complements requirement based verification (testing and analysis) by establishing the completeness of testing, to ratify absence of unintended functions and verification of code structure as per software level. The structural coverage should be carried out with due diligence and traceability should be captured between code structure and test cases. Incidental coverage (coverage by chance) need to be avoided and structure coverage should not be rationalized for the lack of robustness test cases. Requirement completeness (depth of requirements- to cover all the minute details of requirements) and coverage (breadth of requirements-to cover all the required functionalities) analysis are necessary independent activities and should not be substituted by structural coverage analysis.
2013-09-17
Journal Article
2013-01-2281
Jan Grymlas, Frank Thielecke
This paper focuses on the virtual integration and test approach used for the evaluation of an automation system developed for the multifunctional operation of fuel cells in commercial aircraft. In order to accomplish the virtual integration a model of the overall automation system is linked with a dynamic model of the complete fuel cell system. For this purpose a modeling approach for complex physical systems is described in this paper. During virtual testing various simulation runs are executed based on automatically generated test cases, which cover a complete flight mission. For this reason a flight mission is modeled as a Statechart that includes next to time- based flight phases also potential events and malfunctions (e.g. engine flame-out, cargo fire). An algorithm is described, which can find all possible state combinations including parallel event sequences.
2013-09-17
Journal Article
2013-01-2277
Emily Dallara, Joshua Kusnitz, Marty Bradley
Current methods of life cycle assessment (LCA) include input-output (IO) models and process-based LCA. These methods either require excessive effort and time to reach a conclusion (process LCA) or do not adequately model how a change in a product's design will affect the environmental footprint (IO LCA). A variation of process-based LCA developed specifically for aircraft is presented in this study. A tool implementing this LCA, “qUWick,” is rapid and easily applicable to multi-disciplinary design optimization of aircraft. Models developed for the material production, manufacturing, usage, and end-of-life of an aircraft are examined. Outputs of qUWick are discussed for future air vehicles. When compared to process LCAs with similar boundaries, qUWick gives similar results, however qUWick models several stages of an aircraft's life cycle more accurately than other aircraft process-based LCAs.
2013-09-17
Technical Paper
2013-01-2279
Christophe Secheret
Taking advantage of its understanding of the needs, stakes and requirements of the strong safety and security expectation of Nuclear Plants in France, Nexess and Desoutter Industrial tools start to offer leading edge RFID solutions answering people flow management and integrated tooling traceability. These solutions aim to enhance security and safety whilst offering productivity improvements, by covering namely tooling management with specialized furniture, storage and warehouse flow management supported by software integrated equipment. Additional solutions exist as well for the search of FOD when brought for assembly or repair in critical areas of the aircraft. With the raising of Battery wireless tools and the raising concerns of FOD the demand for proven technologies in the aerospace is growing. The aim of this paper is to address leading edge technologies to answer safety, FOD and tooling management concerns on the aerospace assembly lines and on MRO's activities.
2013-09-17
Technical Paper
2013-01-2269
Tiago Machado, Jose C. Pascoa, Francisco Brojo, Carlos Xisto
The use of a magnetic field applied to a gaseous conducting boundary layer flow as been proposed as a mean to control boundary layer losses. The solution of the Navier-Stokes equations together with the induction equation for the magnetic field was numerically obtained using a Finite Volume code. The effects of the magnetic field are introduced into the momentum equations by means of a Lorentz force source term. Further, several turbulence models were modified in order to include the magnetic field perturbation. The computation of the transitional flow on a flat plate was made for several values of the magnetic field, and a relaminarization of the flow was obtained for sufficient high values of the magnetic field. The code was also applied for the computation of the flow around an airfoil as an example application of an high speed high-altitude UAV.
2013-09-17
Technical Paper
2013-01-2271
Jakson Monteiro, Jose C. Pascoa, Carlos Xisto
Cyclogiros have the possibility to provide hovering and achieve forward speeds higher than present day helicopters. Yet, due to the inherent unsteady aerodynamics, most of the research approaches have been based on limited experimental testing of computational fluid dynamics. However, and for a parametric analysis, it is important to provide analytic tools that can help in the preliminary design stage. In this work the complexity of the forward flight modeling will be described using an innovative approach. The present proposed model will be benchmarked against experimental and CFD results, further it will be used to propose rotor geometries for 3 working conditions.
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