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Viewing 1 to 30 of 1711
2017-03-28
Technical Paper
2017-01-0113
Vaclav Jirovsky
Today's vehicles are being more often equipped with systems, which are autonomously influencing the vehicle behavior. The close future is awaiting more systems of the kind and even significant penetration of fully autonomous vehicles in regular traffic is expected by OEMs in Europe around year 2025. The driving is highly multitasking activity and human errors emerge in situations, when he is not able to process and understand the essential amount of information. Future autonomous systems very often rely on some type of inter-vehicular communication. This shall provide the vehicle with similar or higher amount of information, than driver uses in his decision making process. Therefore, currently used, and debatable, 1-D quantity TTC (time-to-collision) will definitely become inadequate. Regardless the vehicle is driven by human or robot, it’s always necessary to know, whether and which reaction is necessary to perform.
2017-03-28
Journal Article
2017-01-1352
David Gardiner
Abstract This paper presents an experimental study of the vapour space flammability of Fuel Ethanol (a high-ethanol fuel for Flexible Fuel Vehicles, commonly known as “E85”) and gasoline containing up to 10% ethanol (commonly known as “E10”). The seasonal minimum vapour pressure limits in specifications for automotive spark ignition fuels are intended, in part, to minimize the formation of flammable mixtures in the headspace of vehicle fuel tanks. This is particularly important at subzero temperatures, where the headspace mixture may not be rich enough to prevent combustion in the presence of an ignition source such as a faulty electrical fuel pump. In the current study, the upper temperature limits of flammability were measured for field samples of “E85” and “E10”, and a series of laboratory-prepared blends of denatured ethanol, Before Oxygenate Blending (BOB) gasoline, and n-butane.
2017-01-10
Technical Paper
2017-26-0336
Ganesh Liladhar Yewale, Abhishek Tapkire, D Radhakrishna, Popat Shejwal, Kaushal Singh, Gaurav Panchal
Abstract VRDE has developed Wankel type rotary engine to achieve high power output & fuel efficiency for indigenization programme of UAVs. This engine is meeting all performance parameters needed for intended aerial vehicle. This paper describes the testing methodology followed by development engineers to prove the endurance and reliability of UAV engine for airworthiness certification. This paper gives the brief about testing carried out on the Wankel engine, failures faced during endurance testing and their rectification to enhance the life of the engine to achieve hundred test cycle mark. This paper also briefs about the test set up, endurance test cycles simulating the practical operating conditions.
2016-11-07
Technical Paper
2016-22-0006
John R. Humm, Narayan Yoganandan, Frank A. Pintar, Richard L. DeWeese, David M. Moorcroft, Amanda M. Taylor, Brian Peterson
The objective of the present exploratory study is to understand occupant responses in oblique and side-facing seats in the aviation environment, which are increasingly installed in modern aircrafts. Sled tests were conducted using intact Post Mortem Human Surrogates (PMHS) seated in custom seats approximating standard aircraft geometry. End conditions were selected to represent candidate aviation seat and restraint configurations. Three-dimensional head center-of-gravity linear accelerations, head angular velocities, and linear accelerations of the T1, T6, and T12 spinous processes, and sacrum were obtained. Three-dimensional kinematics relative to the seat were obtained from retroreflective targets attached to the head, T1, T6, T12, and sacrum. All specimens sustained spinal injuries, although variations existed by vertebral level.
2016-09-20
Technical Paper
2016-01-1991
Syed J. Khalid
Abstract Aircraft subsystems essential for flight safety and airworthiness, including flight controls, environmental control system (ECS), anti-icing, electricity generation, and starting, require engine bleed and power extraction. Predictions of the resulting impacts on maximum altitude net thrust(>8%), range, and fuel burn, and quantification of turbofan performance sensitivities with compressor bleed, and with both high pressure(HP) rotor power extraction and low pressure(LP) rotor power extraction were obtained from simulation. These sensitivities indicated the judicious extraction options which would result in the least impact. The “No Bleed” system in Boeing 787 was a major step forward toward More Electric Aircraft (MEA) and analysis in this paper substantiates the claimed benefits.
2016-09-20
Technical Paper
2016-01-1999
Debabrata Pal, Frank Feng
Abstract In 3-phase AC application, there is additional heat dissipation due to skin effects and proximity effects in bus bars. In addition, when the 3- phase AC is used to drive a motor at high fundamental frequency, for example between 666 Hz and 1450 Hz, there are higher bus bar losses due to presence of higher frequency harmonic content. High frequency current carrying bus bars in aircraft power panels are typically cooled by natural convection and radiation. In this paper a thermal and electrical finite element analysis (FEA) is done for a bus bar system. For electrical loss modeling, 3D electromagnetic FEA is used to characterize losses in three parallel bus bars carrying AC at various frequencies. This loss analysis provides correlation of heat loss as function of frequency. A method is presented where this AC loss is incorporated using computational fluid dynamics (CFD) based thermal model.
2016-09-20
Technical Paper
2016-01-2025
Amir Fazeli, Adnan Cepic, Susanne Reber
Abstract Aircraft weight and center of mass are two critical design and operational parameters that have to be within a design envelope to ensure a safe and efficient operation of aircraft. Previous efforts to accurately determine aircraft weight and center of mass before takeoff using landing gear shock strut pressures have failed due to the distortion of measured pressures by shock strut seal friction. Currently, aircraft loading process is controlled with loading sheets and passenger/cargo weight estimation as there are no online measurement systems that can accurately and efficiently estimate aircraft weight and determine the center of mass location before takeoff. However, errors in loading sheets, shifting cargo and errors in weight estimation could lead to incorrect loading of aircraft and, consequently, increase the risk of accidents, particularly in cargo flights.
2016-09-20
Technical Paper
2016-01-2043
Richard C. Millar, Thomas Mazzuchi, Haflidi Jonsson
Abstract The SPA-10 project, sponsored by U.S. National Science Foundation, is to acquire and qualify a replacement for the retired T-28 “storm penetration” aircraft previously used to acquire meteorological data to enable understanding and modelling of mid-continent thunderstorms. The National Science Foundation selected the Fairchild A-10 (bailed from the U.S. Air Force) as the platform to be adapted to perform the storm penetration mission to altitudes of eleven kilometers, and funded Naval Postgraduate School’s Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) as prime contractor. An expert panel conducted a review of the SPA-10 project in 2014 and recommended a risk analysis addressing hazards to the aircraft and pilots, such as icing, hail, turbulence and lightning. This paper presents the results of the risk analysis performed in response to this need, including recommended mitigations.
2016-09-20
Technical Paper
2016-01-2040
Satya Swaroop Panda, Uday Kishore Tammiraju
Abstract Most of the real world problems pose practical challenges for making decisions primarily due to availability of limited data. Quantification of risk and assessment of structural reliability becomes difficult in such scenarios. Techniques for performing safety analysis for such problems are discussed in this paper. While complete characterization of a system behavior may be difficult with limited data of its response, statistical models based on extreme value theory provide the basis for making decisions with reasonable confidence. The same may not be true, however, for such structures early in their design cycle due to limited experience of their performance. In such cases response surface methodology can be very useful in determination of risk and suitably making modifications to the design to improve the reliability of the component or system. Applications of these methods for some real world scenarios are demonstrated.
2016-09-20
Journal Article
2016-01-1976
Kiran Thupakula, Adishesha Sivaramasastry, Srikanth Gampa
Abstract Aviation safety is one of the key focus areas of the aerospace industry as it involves safety of passengers, crew, assets etc. Due to advancements in technology, aviation safety has reached to safest levels compared to last few decades. In spite of declining trends in in-air accident rate, ground accidents are increasing due to ever increasing air traffic and human factors in the airport. Majority of the accidents occur during initial and final phases of the flight. Rapid increase in air traffic would pose challenge in ensuring safety and best utilization of Airports, Airspace and assets. In current scenario multiple systems like Runway Debris Monitoring System, Runway Incursion Detection System, Obstacle avoidance system and Traffic Collision Avoidance System are used for collision prediction and alerting in airport environment. However these approaches are standalone in nature and have limitations in coverage, performance and are dependent on onboard equipment.
2016-04-05
Journal Article
2016-01-0497
Brian Falzon, Wei Tan
Abstract The development of the latest generation of wide-body carbon-fibre composite passenger aircraft has heralded a new era in the utilisation of these materials. The premise of superior specific strength and stiffness, corrosion and fatigue resistance, is tempered by high development costs, slow production rates and lengthy and expensive certification programmes. Substantial effort is currently being directed towards the development of new modelling and simulation tools, at all levels of the development cycle, to mitigate these shortcomings. One of the primary challenges is to reduce the extent of physical testing, in the certification process, by adopting a ‘certification by simulation’ approach. In essence, this aspirational objective requires the ability to reliably predict the evolution and progression of damage in composites. The aerospace industry has been at the forefront of developing advanced composites modelling tools.
2016-04-05
Technical Paper
2016-01-1463
Jeffrey Aaron Suway, Judson Welcher
Abstract It is extremely important to accurately depict photographs or video taken of a scene at night, when attempting to show how the subject scene appeared. It is widely understood that digital image sensors cannot capture the large dynamic range that can be seen by the human eye. Furthermore, todays commercially available printers, computer monitors, TV’s or other displays cannot reproduce the dynamic range that is captured by the digital cameras. Therefore, care must be taken when presenting a photograph or video while attempting to accurately depict a subject scene. However, there are many parameters that can be altered, while taking a photograph or video, to make a subject scene either too bright or too dark. Similarly, adjustments can be made to a printer or display to make the image appear either too bright or too dark. There have been several published papers and studies dealing with how to properly capture and calibrate photographs and video of a subject scene at night.
2015-09-15
Technical Paper
2015-01-2429
Rickard Olsen, Kerstin Johansen, Magnus Engstrom
Abstract The increased diffusion of cooperation between humans and robotics in manufacturing systems is one of the next things to implement within robotics. Since the computer power gets more and more powerful, the possibilities increase to achieve safer working environment, due to that all safety signals demands fast management of data. This could lead to a possibility to work closer and more direct with a robot, using the robot as a third hand. Within an EU FW7 funded project called LOCOMACHs (Low Cost Manufacturing and Assembly of Composite and Hybrid Structures) there are one study focusing on how to support a future higher TRL-leveled HMI cell (Human Machine Interaction) in an assembly task. The main objective in this paper is to present how different external safety systems could support the whole HMI assembly cell to work properly in an industrial context.
2015-09-15
Technical Paper
2015-01-2461
Enrico Troiani, Maria Pia Falaschetti, Sara Taddia, Alessandro Ceruti
Abstract The high number of hull losses is a main concern in the UAV field, mostly due to the high cost of on-board equipment. A crashworthiness design can be helpful to control the extent and position of crash impact damage, minimizing equipment losses. However, the wide use of composite materials has recently put the accent on the lack of data about the behavior of these structures under operative loads, such as the crash conditions. This paper presents the outcome of a set of tests carried out to achieve a controlled crush of UAV structures, and to maximize the Specific Energy Absorption. In this work, a small-scale experimental test able to characterize the energy absorption of a Carbon-fiber-reinforced polymer under compression was developed introducing self-supporting sinusoidal shape specimens, which avoid the need for complex anti-buckling devices.
2015-09-15
Technical Paper
2015-01-2471
Alessandro Ceruti, Simone Curatolo, Alessandro Bevilacqua, Piergiovanni Marzocca
Abstract The maturity reached in the development of Unmanned Air Vehicles (UAVs) systems is making them more and more attractive for a vast number of civil missions. Clearly, the introduction of UAVs in the civil airspace requiring practical and effective regulation is one of the most critical issues being currently discussed. As several civil air authorities report in their regulations “Sense and Avoid” or “Detect and Avoid” capabilities are critical to the successful integration of UAV into the civil airspace. One possible approach to achieve this capability, specifically for operations beyond the Line-of-Sight, would be to equip air vehicles with a vision-based system using cameras to monitor the surrounding air space and to classify other air vehicles flying in close proximity. This paper presents an image-based application for the supervised classification of air vehicles.
2015-09-15
Technical Paper
2015-01-2590
Yufei Lin, Zakwan Skaf, Ian Jennions
Abstract In the past few decades the number of airplanes has increased dramatically and aircraft systems have become increasingly more complex. Under these conditions, the next generation of airplanes will undergo substantial changes and will make significant technical progress to improve operational safety. This vision is entirely consistent with the adoption of Integrated Vehicle Health Management (IVHM) technology which uses merging of interdisciplinary trends to carry out safe and effective vehicle operation. Hitherto, IVHM has made much progress in the realm of maintenance and operation, but little on safety assessment. This paper discusses the issues around how IVHM could be used to aid the operational safety assessment in the aviation industry. Special attention is paid to existing safety assessment methods, and some challenges and promising research directions are highlighted.
2015-09-15
Technical Paper
2015-01-2536
Rinky Babul Prasad, Vinukonda Siddartha
Abstract Recent years have seen a rise in the number of air crashes and on board fatalities. Statistics reveal that human error constitutes upto 56% of these incidents. This can be attributed to the ever growing air traffic and technological advancements in the field of aviation, leading to an increase in the electronic and mechanical controls in the cockpit. Accidents occur when pilots misinterpret gauges, weather conditions, fail to spot mechanical faults or carry out inappropriate actions. Currently, pilots rely on flight manuals (hard copies or an electronic tablet) to respond to an emergency. This is prone to human error or misinterpretation. Also, a considerable amount of time is spent in seeking, reading, interpreting and implementing the corrective action. The proposed augmented head mount virtual assist for the pilot eliminates flight manuals, by virtually guiding the pilot in responding to in-flight necessities.
2015-09-15
Technical Paper
2015-01-2443
Nivedita Chanda
Abstract Aircrafts use Transponder for transmitting data to Air Traffic Control ground stations. Transponders automatically transmit a unique four-digit code when they receive a radio signal sent by radar. But when Transponder is shut down, and the redundant transponder fails to operate, there is no system within the aircraft which can continue transmitting altitude and important data to ATC ground stations. This has necessitated active research work to fundamentally design better and effective communication systems. At present, there is no evident redundant system to transponder unlike in case of Power-Plants, three-fold reliable, safety cum redundant power supply system are present. The present work introduces a novel design ‘RTSA’ which can be effective in catering safe transmission of emergency signal.
2015-09-15
Technical Paper
2015-01-2449
Solange Baena, Joseph K-W Lam, Craig Lawson
Abstract This paper focuses on the investigation of the nature, process and effects of ice accretion on different feed pump strainers upstream of the aircraft feeding system. A suitable test rig was designed to circulate Jet A-1 containing water/ice contaminants at cold temperatures through the strainers. Following an extensive literature review, a number of screening tests were performed. These provided a strong base for an exhaustive study of fuel icing in the dynamic environment offered by the test rig. The effects of the rate of fuel cooling on the nature of ice were examined. As expected, it was observed that the yield of ice generated on the mesh screen increased with the water concentration in the fuel. It was also revealed that at higher cooling rates, a crust of snow formed on top of softer ice on the mesh screen.
2015-09-15
Technical Paper
2015-01-2458
Giuseppe Sirigu, Manuela Battipede, Piero Gili, Mario Cassaro
Abstract The future revolution of the air traffic system imposes the development of a new class of Flight Management Systems (FMS), capable of providing the aircraft with real-time reference flight parameters, necessary to fly the aircraft through a predefined sequence of waypoints, while minimizing fuel consumption, noise and pollution emissions. The main goal is to guarantee safety operations while reducing the aircraft environmental impact, according to the main international research programs. This policy is expected to affect also the Unmanned Aerial Systems (UASs), as soon as they will be allowed to fly beyond the restricted portions of the aerospace where they are currently confined. In the future, in fact, UASs are expected to fly within the whole civilian airspace, under the same requirements deriving from the adoption of the Performance Based Navigation (PBN).
2015-09-15
Technical Paper
2015-01-2435
Ramakrishnan Murthy
Abstract One major problem that any product (say Motor, engines etc.) which converts electrical energy into a mechanical energy would have is resonance. It has tendency to damage any material when the products operating frequency matches the resonant frequency. The major consequences of this resonant frequency in Flight at run-time could be catastrophic. Generally it is a practice to avoid running at the resonant frequency. This is done as a fixed method where the systems are designed not to run on resonant frequency, i.e. a subsystem in a system is now being designed for that system alone which will not match the resonant frequency. But the same subsystem may not be suitable for some other system. Hence this requires multiple designs. However this idea is to make a design generic where any subsystem can be used in any system irrespective of its resonant frequency. The technique uses the PID algorithm. This method will be helpful is having a single design for different systems
2015-09-15
Technical Paper
2015-01-2478
Tobias Kreitz, Riko Bornholdt, Matthias Krings, Karsten Henning, Frank Thielecke
Abstract The paradigm shift to focus on an enhancement of existing aircraft systems raises the question which of the many possible incremental improvements results in an advantageous solution still considering all existing requirements. Hence, new methodologies for aircraft system design are a prerequisite to cope with such huge and complex design spaces. In the case of flight control system optimization, major design variables are the control surface configuration and actuation as well as their functional allocation. Possible architecture topologies have to be verified inter alia with respect to system safety requirements. In this context, flight dynamic characteristics and handling qualities of the fully operational as well as of several degraded system states of each topology have to be evaluated and checked against common specifications. A model-based verification of the requirements is favorable, resulting in a rapid reduction of the design space.
2015-09-15
Journal Article
2015-01-2385
Richard C. Millar
Abstract Unmanned aviation systems (UAS) acquired for US Navy for military roles are developed in the context of NAVAIR's rigorous and well-established policies, procedures and processes employed in the acquisition and development of manned aircraft. A key process is the preparation and approval of interim flight clearances (IFC) prior to flight test to ensure the aircraft is airworthy and thus safe to operate. Due to the perceived risks of UAS experimental flight test, the use of this process has been mandated for all Navy organizations, including use of commercially available UAS in research projects. This policy has proved to be a challenge, impeding and discouraging the use of UAS in research and experimental projects. Currently, the cost of compliance is unaffordable and IFC preparation and approval time are inconsistent with research cycle time expectations.
2015-09-15
Journal Article
2015-01-2440
Robert Moehle, Jason Clauss
Abstract Labor costs rank second only to fuel in expenses for commercial air transports. Labor issues are a growing concern in the airline industry, with an impending worldwide pilot shortage. One solution proposed and requested by some of the industry leaders is to allow a single flight crew member to operate the aircraft. Safety concerns represent the dominant barrier to single-pilot Part 121 operations. The FAA and Congress consistently demonstrate a bias toward conservatism in their regulation of airlines and commercial aircraft. Bureaucrats and the general public fall prey to isolated news stories that highlight pilot error and anchor their viewpoint on further regulating a two-person crew. Yet, in an alarming spate of recent airline accidents, the presence of multiple crewmembers did nothing to prevent, and actually may have contributed to, the crash. Technology is not the problem.
2015-09-15
Journal Article
2015-01-2392
Matthew Marino, Alessandro Gardi, Roberto Sabatini, Trevor Kistan
RETRACTED: This paper gives the concepts and mathematically models required for the development of the Multi Objective Trajectory Optimization (MOTO) functionalities to be implemented into the next generation of ATM system. MOTO algorithms are introduced whereby data from various sources are utilized to optimize flight paths for various user defined objectives. The algorithms require digital resources of weather, aircraft data, metrological maps and air traffic. These will be used in conjunction with various mathematical models to compute trajectories that minimize various objectives such as fuel, emissions and operational cost. The automated 4D trajectory computation algorithms are restricted to single flight level to not violate the current layered vertical air route structure for the cruise phase of flight.
2015-09-15
Technical Paper
2015-01-2434
Tian Lirong, Mu Ming
Abstract In recent year, with the booming of Chinese economy and domestic civil air transportation market, China's aircraft manufacturers have been trying to develop their own commercial aircraft and changing from the subcontracting-manufacturer to aircraft developer, which turned to be a very hard task. One of the main challenges in front of China's aircraft manufacturers and airborne equipment suppliers is how to apply the airworthiness standards, such as ARP4754A, ARP4761, DO-178B(C) and DO-254, etc, into their engineering practice. Chinese companies are struggling in improving their capabilities to satisfy certification requirements and are making some remarkable progress these years. The paper first introduces the current status of Chinese aviation industry, and then the challenges to China's airborne equipment suppliers are analyzed. Based on these, the customization considerations of airworthiness standards and ARP4754 Practice in Chinese context are discussed.
2015-09-15
Technical Paper
2015-01-2441
Ahmet Oztekin
Abstract This paper outlines an analytical framework to perform a data-driven, risk-based assessment of Air Traffic Control (ATC) facilities. Safety associated with an ATC facility is modeled as an influence network using a set of risk factors. A novel hybrid approach employing Adaptive-Network based Fuzzy Inference Systems is introduced to propagate the model. Statistical analysis of system-wide data for each risk factor is performed to identify outliers and understand underlying distributions. They are then used to define Fuzzy Membership Functions for model variables. Analytical Hierarch Process (AHP) is used to determine rules required by the model's inference engine. Finally, the methodology is applied to a set of ATC facilities using real data.
2015-09-15
Technical Paper
2015-01-2463
Giacomo Frulla, Enrico Cestino, Piero Gili, Michele Visone, Domenico Scozzola
Abstract The problem of wing shape modification under loads in order to enhance the aircraft performance and control is continuously improving by researchers. This requirement is in contrast to the airworthiness regulations that constraint stiffness and stress of the structure in order to maintain structural integrity under operative flight conditions. The lifting surface modification is more stringent in those cases, such as UAV configurations, where the installed power is limited but the variety of operative scenario is wider than in conventional aircraft. A possible solution for adaptive wing configuration can be found in the VENTURAS Project idea. The VENTURAS Project is a funded project with the aim of improve the wind turbine efficiency by means of introducing a twisting capability for the blade sections according to the best situation in any wind condition. The blade structure is composed by two parts: 1) internal supporting element, 2) external deformable envelope.
2015-09-15
Journal Article
2015-01-2568
Michele Castellani, Yves Lemmens, Jonathan Cooper
Abstract Flight loads calculations play a fundamental role in the development and certification of an aircraft and have an impact on the structural sizing and weight. The number of load cases required by the airworthiness regulations is in the order of tens of thousands and the analysis must be repeated for each design iteration. On large aircraft, CS-25 explicitly requires taking into account for loads prediction, airframe flexibility, unsteady aerodynamics and interaction of systems and structure, leading to computationally expensive numerical models. Thus there is a clear benefit in speeding-up this calculation process. This paper presents a methodology aiming to significantly reduce the computational time to predict loads due to gust and maneuvers. The procedure is based on Model Order Reduction, whose goal is the generation of a Reduced Order Model (ROM) able to limit the computational cost compared to a full analysis whilst retaining accuracy.
2015-09-15
Technical Paper
2015-01-2520
Thabet Kacem, Jeronymo Carvalho, Duminda Wijesekera, Paulo Costa, Márcio Monteiro, Alexandre Barreto
Abstract Automatic Dependent Surveillance Broadcast (ADS-B) [1] is a technology that can be viewed either as a complement or as an alternative to current radar-based surveillance techniques. Despite its many benefits, this technology suffers from the security flaw of having its messages sent as clear text broadcasts, which makes it vulnerable to several kinds of attacks affecting the authenticity and integrity of ADS-b messages - a problem we addressed with a security framework presented in previous work [2]. In this paper, we propose to enhance that initial work by using keyed-hash message authentication code [3] (HMAC) to ensure the authenticity and integrity of ADS-B messages. The proposed improvements include changing the structure of the security-related data and, more importantly, adding a cognitive risk adaptive module. These improvements resulted in four main contributions.
Viewing 1 to 30 of 1711