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Viewing 61 to 90 of 20019
2017-09-19
Journal Article
2017-01-2024
Natasha L. Schatzman, Narayanan Komerath, Ethan A. Romander
Abstract The blade crossing event of a coaxial counter-rotating rotor is a potential source of noise and impulsive blade loads. Blade crossings occur many times during each rotor revolution. In previous research by the authors, this phenomenon was analyzed by simulating two airfoils passing each other at specified speeds and vertical separation distances, using the compressible Navier-Stokes solver OVERFLOW. The simulations explored mutual aerodynamic interactions associated with thickness, circulation, and compressibility effects. Results revealed the complex nature of the aerodynamic impulses generated by upper/lower airfoil interactions. In this paper, the coaxial rotor system is simulated using two trains of airfoils, vertically offset, and traveling in opposite directions. The simulation represents multiple blade crossings in a rotor revolution by specifying horizontal distances between each airfoil in the train based on the circumferential distance between blade tips.
2017-09-19
Technical Paper
2017-01-2019
Rakshath G Poojary, Mohammed Ali Jouhar, Abubakar K
Abstract Human Powered Helicopter which uses man power to operate. The main aim of this paper is to design commercially available vehicle for an Adventure Sporting under 5-6 lakh Indian Rupees. This structural design is extremely lightweight and strong. The product is designed in such a way that it can be easily assembled and dismantled for transportability and storage. We developed an aero-structural optimization scheme for rotor design, including an aerodynamic model with included ground effect prediction, finite-element analysis and integrated composite failure analysis, and a detailed weight estimation scheme. This was solely build on computer CAD models. This design includes the use of gear box to increase the output. The Aerodynamic analysis was done using CFD and BET (blade element theory-Bhramwell) in MATLAB.
2017-09-19
Technical Paper
2017-01-2034
Bailey Hall, Benjamin Palmer, Tyler Milburn, Luis Herrera, Bang Tsao, Joseph Weimer
Abstract Future aircraft will demand a significant amount of electrical power to drive primary flight control surfaces. The electrical system architecture needed to source these flight critical loads will have to be resilient, autonomous, and fast. Designing and ensuring that a power system architecture can meet the load requirements and provide power to the flight critical buses at all times is fundamental. In this paper, formal methods and linear temporal logic are used to develop a contactor control strategy to meet the given specifications. The resulting strategy is able to manage multiple contactors during different types of generator failures. In order to verify the feasibility of the control strategy, a real-time simulation platform is developed to simulate the electrical power system. The platform has the capability to test an external controller through Hardware in the Loop (HIL).
2017-09-19
Technical Paper
2017-01-2052
K Friedman, G Mattos, K Bui, J Hutchinson, A Jafri, J Paver PhD
Abstract Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic dummies such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted dummy to impact components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, a wide range of seat back materials, and airbags. The HIC, and other injury measures such as Nij, can be calculated during such impacts. A minimum test pulse, with minimum allowable acceleration vs time boundaries, is defined as part of the regulations for a frontal impact. In this study the effects of variations in decelerations that meet the requirements are considered.
2017-09-19
Technical Paper
2017-01-2054
K Friedman, G Mattos, K Bui, J Hutchinson, A Jafri, J Paver
Abstract Aircraft seating systems are evaluated utilizing a variety of impact conditions and select injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic test devices such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted ATD to engage components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, various plastic and composite fascia, and a wide range of seat back materials. The HIC, and other injury measures such as Nij, can be calculated during such impacts. It has been shown in other safety applications that the friction between a headform and contact surface can affect the test results.
2017-09-19
Technical Paper
2017-01-2053
Jim Stabile
Since oxygen has been a part of the aircraft system it has always been managed using a difficult metric to understand.......PSI. Today's technology has allowed us to efficiently and inexpensively convert PSI into a timed based metric which allows for improved oxygen management and a method which provides an interface between two important energy aircraft resources (fuel and oxygen). These resources have inverse consumption rates tied directly to the altitude of the aircraft. Using time as the management metric, the pilot can balance these 2 resources during any oxygen contingency by varying the altitude of the aircraft.. This allows for regulatory fuel savings and an increase in operational safety This program diverges from traditional thinking in that it applies an information and skill based solution to a system that has otherwise been viewed as a hardware problem.
2017-09-19
Technical Paper
2017-01-2039
Michael Sielemann, Changsoo Lee, Victor-Marie LeBrun, Chiwoo Ahn, Arnaud Colleoni, Dongkyu Lee, JeongSeok Lee, Anh Nguyen, Katrin Proelss, Hyon Min Yoon
Abstract Thermal management on aircraft has been an important discipline for several decades. However, with the recent generations of high performance aircraft, thermal management has evolved more and more into a critical performance and capability constraint on the whole aircraft level. Fuel continues to be the most important heat sink on high performance aircraft, and consequently the requirements on thermal models of fuel systems are expanding. As the scope of modeling and simulation is widened in general, it is not meaningful to introduce a new isolated modeling and simulation capability. Instead, thermal models must be derived from existing model assets and eventually enable integration across several physical domains. This paper describes such an integrated approach based on the Modelica Fuel System Library and the 3DExperience Platform.
2017-09-19
Technical Paper
2017-01-2070
Nicholas Anderson, Joseph Gao, Eric Whitman, Srikanth Gururajan
Abstract Recent advances in Small Unmanned Aerial Systems (SUAS) or drone technologies has resulted in their widespread use in a number of civilian applications, such as aerial imaging, infrastructure inspection, precision agriculture, among others. While this technology is accessible for everyone, it still requires a highly skilled operator to be able to successfully operate these drones in a safe and efficient manner. At the same time, developments in Virtual/Augmented Reality (V/AR) technologies present opportunities for combining the two into novel applications and use cases by providing an intuitive interface for interacting with the drones - opening up possibilities for safe and effective use of drones by relatively untrained operators.
2017-09-19
Technical Paper
2017-01-2096
Rainer Mueller, Matthias Vette, Aaron Geenen, Tobias Masiak
Abstract Assembly processes in aircraft production are difficult to automate due to technical risks. Examples of such technical challenges include small batch sizes and large product dimensions as well as limited work space for complex joining processes and organization of the assembly tasks. A fully automated system can be expensive and requires a large amount of programming knowledge. For these reasons, ZeMA believes a semi-automated approach is the most effective means of success for optimizing aircraft production. Many methods can be considered semi automation, one of which is Human-Robot-Collaboration. ZeMA will use the example of a riveting process to measure the advantages of Human-Robot-Collaboration systems in aircraft structure assembly. In the assembly of the aircraft aft section the pressure bulkhead is mounted with a barrel section using hundreds of rivets. This assembly process is a non-ergonomic and burdensome task in which two humans must work cooperatively.
2017-09-19
Technical Paper
2017-01-2093
Thorsten Dillhoefer
Ever increasing process applications inspire us, as suppliers of aircraft, structural-assembly, and equipment to design innovative and modular, manufacturing cells in compliance with modern specification. The result is the new highly flexible Aerospace application specific robot identified as “POWER RACe”. This paper describes how benchmarks for flexible automated drilling and fastening are being achieved with the Power RACe technology platform.
2017-09-19
Technical Paper
2017-01-2077
John McClelland, Michael Morgan, Caroline McClory, Colm Higgins, Rory Collins, Adrian Murphy, Yan Jin
The need to drill several million holes per aircraft through composite and hybrid material stacks is a large challenge for the aerospace assembly process. The ability to produce high quality holes for the lowest tooling costs is at the forefront of requirements for aircraft assembly factories worldwide. Consequently, much research has been conducted into tool design and development, however, the effect of drilling platform characteristics has not been well covered in literature. Respectively, this research has compared the drilling abilities of a 5-axis precision CNC platform, a hybrid parallel kinematic machine and an articulated robotic arm fitted with a drilling module. In-process force measurement and post process hole and tool analysis methods were used to better understand the effect of static and dynamic platform characteristics on the achievable hole quality, cycle time and tool wear when drilling aerospace metal alloy stacks.
2017-09-19
Technical Paper
2017-01-2110
Ashutosh Kumar Jha, Prakash Choudhary
Abstract The complexity of software development is increasing unprecedentedly with every next generation of aircraft systems. This requires to adopt new techniques of software design and verification that could optimize the time and cost of software development. At the same time these techniques need to ensure high quality of software design and safety compliance to regulatory guidelines like DO-178C [1] and its supplements DO-330[2] and DO-331[3]. To arrive at new technologies one has to evaluate the alternate methods available for software design by developing models, integration of models, auto-code generation, auto test generation and also the performance parameters like time, effort, reuse and presentation needs to be evaluated. We have made an attempt to present summary of alternate design concept study, and edge of MBD over other design techniques.
2017-09-19
Technical Paper
2017-01-2109
Kiran Thupakula
Abstract Airport environments consist of several moving objects both in the air and on the ground. In air moving objects include aircraft, UAVs and birds etc. On ground moving objects include aircraft, ground vehicles and ground personnel etc. Detecting, classifying, identifying and tracking these objects are necessary for avoiding collisions in all environmental situations. Multiple sensors need to be employed for capturing the object shape and position from multiple directions. Data from these sensors are combined and processed for object identification. In current scenario, there is no comprehensive traffic monitoring system that uses multisensor data for monitoring in all the airport areas. In this paper, for explanation purposes, a hypothetical airport traffic monitoring system is presumed that uses multiple sensors for avoiding collisions.
2017-09-19
Technical Paper
2017-01-2113
Michael Schultz
Abstract Passenger boarding is always part of the critical path of the aircraft turnaround: both efficient boarding and online prediction of the boarding progress are essential for a reliable turnaround progress. However, the boarding progress is mainly controlled by the passenger behavior. A fundamental scientific approach for aircraft boarding enables the consideration of individual passenger behaviors and operational constraints in order to develop a sustainable concept for enabling a prediction of the boarding progress. A reliable microscopic simulation approach is used to model the passenger behavior, where the individual movement is defined as a one-dimensional, stochastic, and time/space discrete transition process. The simulation covers a broad range of behaviors and boarding strategies as well as the integration of new technologies and procedures.
2017-09-19
Technical Paper
2017-01-2107
Thorsten Kiehl, Jan Philip Speichert, Ethan Higgins, Ralf God
Abstract For an “end-to-end passenger experience that is secure, seamless and efficient” the International Air Transport Association (IATA) proposes Near Field Communication (NFC) and a single token concept to be enablers for future digital travel. NFC is a wireless technology commonly utilized in Portable Electronic Devices (PEDs) and contactless smart cards. It is characterized by the following two attributes: a tangible user interface and secured short range communication. While manufacturers are currently adapting PED settings to enable NFC in the flight mode, the integration and use of this technology in aircraft cabins still remains a challenge. There are no explicit qualification guidelines for electromagnetic compatibility (EMC) testing in an aircraft environment available and there is a lack of a detailed characterization of NFC equipped PEDs.
2017-09-19
Technical Paper
2017-01-2125
Mohammad Barkat, Vivek Karan, Pradeep N
Abstract The exponential increase in the number of aircrafts and air travelers has triggered new innovations which aim to make airline services more reliable and consumer friendly. Quick and efficient maintenance actions with minimum downtime are the need of the hour. Areas that have a large potential for improvement in this regard are the real time use of diagnostic data, filtering/elimination of nuisance faults and machine learning capabilities with respect to maintenance actions. Although, numerous LRUs installed on the aircraft generate massive amounts of diagnostic data to detect any possible issue or LRU failure, it is seldom used in real time. The turnaround time for LRU maintenance can be greatly reduced if the results of the diagnostics conducted during LRU normal operation is relayed to ground stations in real-time. This enables the maintenance engineers to plan ahead and initiate maintenance actions well before the aircraft lands and becomes available for maintenance.
2017-09-19
Technical Paper
2017-01-2121
Greg Parlier
The US Department of Defense (DoD) operates the most complex global supply chain in the world. However, effectively integrating production planning, maintenance operations, inventory systems, and distribution policies has been a persisting strategic challenge for the logistics enterprise supporting the DoD. Neither DoD nor the Congressional Budget Office has been able to establish a well-defined linkage between Operations and Maintenance resource funding levels and the resulting readiness of military units. For nearly three decades the Government Accountability Office has attributed these inadequacies to poor demand forecasting, ineffective inventory management, and inadequate strategic planning. To address these persisting problems the US Army established the project to Transform Army Supply Chains (TASC) in order to investigate the nature, causes, and consequences of demand uncertainty and supply variability.
2017-09-19
Technical Paper
2017-01-2120
David Hawkins
The challenges faced by both industry, government and the armed forces place increasing pressure on availability, budgets and resources necessitating a re-think of PPP and PBL contracting models to create greater integration to enhance performance in support of the war fighter. equally important is the development of increased synergies across international partners. The publication of ISO 44001 the international standard for collaborative business relationships championed and driven by the Institute for collaborative working provide a robust an neutral platform which can sit along side current contracting model and integrate a systemic approach to underpin mission critical relationships and exploit the value of collaborative relationships. AS the architect of the model which is embedded in the new standard the aim of this presentation will be to raise awareness to the benefits of greater focus on the relationships which support performance .
2017-09-19
Technical Paper
2017-01-2117
Dirk H. Martinen, Marc Lagalaye, Julien Pfefferkorn, Jean Casteres
Abstract Currently, aircraft system Test Benches are often proprietary systems, specifically designed and configured for a dedicated System Under Test (SUT). Today, no standards for configuration, data communication, and data exchange formats are available for avionics Test Benches. This leads to high Test Bench development costs and redundant activities between aircraft system suppliers and airframers. In the case of obsolescence issues for test system components, it is very costly to replace the respective parts as a high integration and reconfiguration effort is required. In the scope of an R&T project, involving several test system suppliers and aircraft system suppliers as well as Airbus as an aircraft manufacturer, a generic and modular architecture for an open test environment is under development. A further goal of the Virtual and Hybrid Testing Next Generation (VHTNG) research project is to prepare a set of open standards for the interfaces to this architecture.
2017-09-19
Technical Paper
2017-01-2164
Markus Kintscher, Hans Peter Monner
Abstract Drag reduction technologies in aircraft design are the key enabler for reducing emissions and for sustainable growth of commercial aviation. Laminar wing technologies promise a significant benefit by drag reduction and are therefore under investigation in various European projects. However, of the established moveable concepts and high-lift systems, thus far most do not cope with the requirements for natural laminar flow wings. To this aim new leading edge high-lift systems have been the focus of research activities in the last five years. Such leading edge devices investigated in projects include a laminar flow-compatible Kruger flap [1] and the Droop Nose concept [2, 3] and these can be considered as alternatives to the conventional slat. Hybrid laminar flow concepts are also under investigation at several research institutes in Europe [4].
2017-09-19
Technical Paper
2017-01-2163
T. P. Aniruddhan Unni
Abstract The automotive underbody diffuser is an expansion device which works by speeding up the air flowing underneath a vehicle. This reduces the pressure below the vehicle thereby increasing downforce. When designed properly, it can lead to a massive gain in downforce and even a reduction in drag. However, a majority of the research and development is restricted to motorsport teams and supercar manufacturers and is highly secretive. Most of the publicly available research has been done for very simple shapes (bluff bodies) to study the effects of ground clearance and rake angle. Very little research has been done for complex geometries with vanes, flaps and vortex generators. This paper aims to investigate the effects of the addition of vanes/strakes and flaps, their location as well as angle, on diffuser performance. Computational Fluid Dynamics simulations have been carried out using three dimensional, steady state RANS equations with the k-ε turbulence model on STAR CCM+ V9.06.
2017-09-19
Technical Paper
2017-01-2162
Narayanan Komerath, Nandeesh Hiremath, Dhwanil Shukla, Joseph Robinson, Ayush Jha, Arun Palaniappan
Abstract This paper brings together three special aspects of bluff-body aeromechanics. Experiments using our Continuous Rotation method have developed a knowledge base on the 6-degree-of-freedom aerodynamic loads on over 50 different configurations including parametric variations of canonical shapes, and several practical shapes of interest. Models are mounted on a rod attached to a stepper motor placed on a 6-DOF load cell in a low speed wind tunnel. The aerodynamic loads are ensemble-averaged as phase-resolved azimuthal variations. The load component variations are obtained as discrete Fourier series for each load component versus azimuth about each of 3 primary axes. This capability has enabled aeromechanical simulation of the dynamics of roadable vehicles slung below rotorcraft. In this paper, we explore the genesis of the loads on a CONEX model, as well as models of a short and long container, using the “ROTCFD” family of unstructured Navier-Stokes solvers.
2017-09-19
Technical Paper
2017-01-2020
Michael Croegaert
Abstract Modern military aircraft platforms are using more and more power which results in an ever increasing power density (SWaP). This in turn, generates more heat that has to be dissipated from the instrument panel and cockpit of the aircraft. Complicating this further is that the use of structural composites which are not efficient conductors of heat and the mission requirements of small heat signatures. Therefore alternative means of extracting the heat from the avionics systems must be used. Liquid cooled systems have the advantage over air cooled systems of a much higher heat transfer rate and the fact that the heat can be transported a significant distance from the source. Liquid cooled avionics have their own challenges as well.
2017-09-19
Technical Paper
2017-01-2042
Matthew Diggs
Abstract A newly-invented "X"-configuration engine utilizing the Scotch yoke mechanism renders potential for the best power/weight ratio of any piston engine. Due to its inherent space and weight efficiency, low stress levels on critical components and low bearing pressures, this new configuration can be designed for aircraft applications using high-pressure 4-stroke diesel cycle with large numbers of cylinders - as many as 24 or 32 cylinders - to minimize engine weight and cross-sectional area. Given the efficiency advantage of 4-stroke turbo-diesel cycle over turbine engines, a study reveals that diesel X-engines may be a preferable solution to turbine engines for airplanes, helicopters and UAVs up to approximately 60000 lbs max. weight @takeoff. Calculations using existing turbine-powered aircraft as a baseline indicate potential for 35 to 50% lower fuel consumption with no compromise to maximum takeoff weight, payload, range, cruise speed, maximum speed or takeoff power.
2017-09-19
Technical Paper
2017-01-2043
Pejman Akbari, Lucas Bermudes
Abstract Reducing the scale of the power engines, pose problems that are not encountered at large scale. Several effects, which are negligible at large scale, prove to dominate these viscous forces driven flows. Particularly, it is useful to investigate unsteady machines at small scales when subject to pressure waves. In this paper, the effects of scale on the propagation of shock waves in narrow shock tubes are studied using analytical and numerical modeling approaches. It is discussed how the size scale can become a decisive factor in governing the behavior of these small-scale devices. The results, in agreement with previous studies, suggest that the wall viscous stresses and heat conduction lead to deviation in flow characteristics compared to ideal shock wave behaviors observed in larger scales. The numerical results show shock-wave attenuation along the length of a narrow shock tube, in accordance with the developed analytical models.
2017-09-19
Technical Paper
2017-01-2030
Benjamin Cheong, Paolo Giangrande, Patrick Wheeler, Pericle Zanchetta, Michael Galea
Abstract High power density for aerospace motor drives is a key factor in the successful realization of the More Electric Aircraft (MEA) concept. An integrated system design approach offers optimization opportunities, which could lead to further improvements in power density. However this requires multi-disciplinary modelling and the handling of a complex optimization problem that is discrete and nonlinear in nature. This paper proposes a multi-level approach towards applying random heuristic optimization to the integrated motor design problem. Integrated optimizations are performed independently and sequentially at different levels assigned according to the 4-level modelling paradigm for electric systems. This paper also details a motor drive sizing procedure, which poses as the optimization problem to solve here. Finally, results comparing the proposed multi-level approach with a more traditional single-level approach is presented for a 2.5 kW actuator motor drive design.
2017-09-19
Technical Paper
2017-01-2046
Pejman Akbari, Ian Agoos
Abstract The Wave Disk Engine (WDE) is a novel engine that has the potential for higher efficiency and power density of power-generation systems. A recent version of wave disk engine architecture known as the two-stage WDE has been studied to address existing challenges of an existing WDE. After describing the engine operation, a cold air-standard thermodynamic model supporting the physical phenomena occurring inside the device is introduced to evaluate performance of the engine. The developed model is general and does not depend on the shape of the wave rotor, it can be applied to radial and axial combustion wave rotors integrated with turbomachinery devices. The analysis starts with predicting internal waves propagating inside the channels of the engine and linking various flow states to each other using thermodynamics relationships. The goal is to find analytical expressions of work output and efficiency in terms of known pressure and temperature ratios.
2017-09-19
Technical Paper
2017-01-2050
Piotr Synaszko, Michal Salacinski, Patryk Ciezak
Abstract The work concerns the selection of measurement parameters for selected non-destructive testing methods of Mi helicopter rotor blades after repair. Considered repair cases involve metal cracks in the sandwich skin and repair damage of honeycomb structure (puncture, dent). In the event of a crack, repair is performed by applying a composite-metal repair package. In case of damage of the core, its broken piece is replaced by a new one and then applied the same metal-composite package as in the case of crack repair. The present work focuses on detecting disbond between skin and core below repair patch and cracks under the repair package. Detecting cracks and assessing their length is important because the repair technology provides the repair package without removing of cracked part of skin. Authors have used laser shearography and C-scan methods for MIA and ET.
2017-09-19
Technical Paper
2017-01-2061
Andrea Cravana, Gerardo Manfreda, Enrico Cestino, Giacomo Frulla, Robert Carrese, Piergiovanni Marzocca
Abstract An accurate aeroelastic assessment of powered HALE aircraft is of paramount importance considering that their behaviour contrasts the one of conventional aircraft mainly due to the use of high aspect-ratio wings with distributed propulsion systems. This particular configuration shows strong dependency of the wing natural frequencies to the propulsion distribution and operating conditions. Numerical and experimental investigations are carried out to better understand the behaviour of flexible wings, focusing on the effect of distributed electric propulsion systems. Several configurations are investigated, including a single propulsion system using an engine pod (a weight with embedded electric motor, a propeller, and the wing-attached structure) installed at selected spanwise positions, and configurations with two and three propellers.
2017-09-19
Technical Paper
2017-01-2059
Enrico Cestino, Giacomo Frulla, Renzo Duella, Paolo Piana, Francesco Pennella, Francesco Danzi
Abstract Future generations of civil aircrafts and unconventional unmanned configurations demand for innovative structural concepts to improve the structural performance, and thus reduce the structural weight, but also to allow possible material couplings to be made. Static and dynamic aeroelastic stability can be altered by these couplings. It is therefore necessary to use an accurate and computationally efficient beam model during the preliminary design phase. A stiffened box, made of isotropic material, but with the stiffeners oriented so that they originate the expected bending/torsion coupling, is considered in the present work. The overall equivalent bending, torsional and coupled stiffness is derived by means of homogenization of the shell skin and of the stiffener plate stiffness. A new equivalent homogeneous orthotropic material is determined and introduced into the equivalent plate configuration.
Viewing 61 to 90 of 20019