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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 100 journals)
Showing 1 - 30 of 30 Journals sorted alphabetically
Acta Astronautica     Hybrid Journal   (Followers: 240)
Advances in Space Research     Full-text available via subscription   (Followers: 283)
Aeronautica     Open Access   (Followers: 20)
Aerospace     Open Access   (Followers: 35)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 147)
Aerospace Science and Technology     Hybrid Journal   (Followers: 268)
AIAA Journal     Full-text available via subscription   (Followers: 659)
Air Force Magazine     Full-text available via subscription   (Followers: 7)
Air Medical Journal     Hybrid Journal   (Followers: 2)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 120)
American Journal of Space Science     Open Access   (Followers: 50)
Annual of Navigation     Open Access   (Followers: 19)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 16)
ASTRA Proceedings     Open Access  
Aviation     Hybrid Journal   (Followers: 10)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 12)
Aviation Week     Full-text available via subscription   (Followers: 197)
Aviation, Space, and Environmental Medicine     Full-text available via subscription   (Followers: 8)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 25)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 26)
Chinese Journal of Aeronautics     Open Access   (Followers: 14)
Ciencia y Poder Aéreo     Open Access  
Control Systems     Hybrid Journal   (Followers: 82)
Cosmic Research     Hybrid Journal   (Followers: 2)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 5)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 18)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 2)
Fatigue of Aircraft Structures     Open Access   (Followers: 10)
Frontiers in Aerospace Engineering     Open Access   (Followers: 9)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 6)
Giroskopiya i Navigatsiya     Open Access  
Gyroscopy and Navigation     Hybrid Journal   (Followers: 175)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 111)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 20)
International Journal of Aeroacoustics     Full-text available via subscription   (Followers: 27)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 16)
International Journal of Aerospace Engineering     Open Access   (Followers: 63)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 16)
International Journal of Aerospace Sciences     Open Access   (Followers: 20)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 2)
International Journal of Aviation Management     Hybrid Journal   (Followers: 4)
International Journal of Aviation Psychology     Hybrid Journal   (Followers: 11)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 4)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 7)
International Journal of Flow Control     Full-text available via subscription   (Followers: 5)
International Journal of Hypersonics     Full-text available via subscription   (Followers: 4)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 7)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 5)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 4)
International Journal of Space Structures     Full-text available via subscription   (Followers: 6)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 1)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 3)
Journal of Aeronautical Materials     Open Access   (Followers: 2)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 9)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 52)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 5)
Journal of Aerospace Information Systems     Full-text available via subscription   (Followers: 1)
Journal of Aerospace Technology and Management     Open Access   (Followers: 2)
Journal of Aircraft     Full-text available via subscription   (Followers: 168)
Journal of Airline and Airport Management     Open Access   (Followers: 7)
Journal of Astrobiology & Outreach     Open Access   (Followers: 1)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 9)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 104)
Journal of Konbin     Open Access  
Journal of Navigation     Hybrid Journal   (Followers: 167)
Journal of Propulsion and Power     Full-text available via subscription   (Followers: 320)
Journal of Space Weather and Space Climate     Open Access   (Followers: 11)
Journal of Spacecraft and Rockets     Full-text available via subscription   (Followers: 470)
Journal of Spatial Science     Hybrid Journal   (Followers: 1)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 3)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 3)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 5)
Life Sciences in Space Research     Hybrid Journal  
Microgravity Science and Technology     Hybrid Journal  
New Space     Hybrid Journal   (Followers: 2)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
npj Microgravity     Open Access  
Population Space and Place     Hybrid Journal   (Followers: 2)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access  
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 6)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 40)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 67)
Propulsion and Power Research     Open Access   (Followers: 22)
REACH - Reviews in Human Space Exploration     Full-text available via subscription  
Recent Patents on Space Technology     Full-text available via subscription  
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 4)
RocketSTEM     Free  
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 23)
Space and Polity     Hybrid Journal   (Followers: 2)
Space Policy     Hybrid Journal   (Followers: 23)
Space Research Today     Full-text available via subscription   (Followers: 39)
Space Safety Magazine     Free   (Followers: 36)
Space Science Reviews     Hybrid Journal   (Followers: 21)
SpaceNews     Free   (Followers: 482)
Transport and Aerospace Engineering     Open Access   (Followers: 4)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 5)
Unmanned Systems     Hybrid Journal   (Followers: 1)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 1)
Вестник УГАТУ     Open Access  
Journal Cover CEAS Aeronautical Journal
  [SJR: 0.499]   [H-I: 6]   [26 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1869-5582
   Published by Springer-Verlag Homepage  [2335 journals]
  • A parametric aircraft fuselage model for preliminary sizing and
           crashworthiness applications
    • Authors: D. B. Schwinn; D. Kohlgrüber; J. Scherer; M. H. Siemann
      Pages: 357 - 372
      Abstract: Abstract The aircraft design process generally comprises three consecutive phases: conceptual, preliminary and detailed design phase. In the conceptual design phase a basis aircraft layout is defined using multidisciplinary analysis procedures. For the structural layout, however, the preliminary design phase is of particular interest as more detailed calculations are introduced to enhance the basic design of the primary structure. Up to date, semi-analytical methods are widely used in this design stage to estimate the structural mass. Although these methods lead to adequate results for the major aircraft components of standard configurations, the evaluation of new configurations (e.g., box wing, blended wing body) or specific structural components with complex loading conditions (e.g., center wing box) is very challenging and demands higher fidelity approaches based on Finite Elements (FE). To accelerate FE model generation in a multidisciplinary design environment, automated processes based on a parametric model description have been introduced. To easily couple in- and output of different tools, a standardized data format—CPACS (Common Parametric Aircraft Configuration Schema)—is used. The versatile structural description in CPACS, the implementation in model generation tools, but also current limitations and future enhancements will be discussed. Recent development on the progress of numerical process chains for structural sizing and crashworthiness applications on solid ground and on water (ditching) are presented in this paper.
      PubDate: 2016-09-01
      DOI: 10.1007/s13272-016-0193-4
      Issue No: Vol. 7, No. 3 (2016)
       
  • Characteristic flight speeds in bats
    • Abstract: Abstract We present empirical data on flight speed for 30 species of Australian bats representing seven families. These data show five characteristic level flight speeds: ‘minimum’ (V min), ‘best efficiency’ (V eff), ‘most common’ (V mode), ‘maximum cruise’ (V mcr) and ‘maximum spurt’ (V msp). Next, we calculate V min, V eff, ‘maximum aerobic’ (V ae), ‘sustainable anaerobic’ (V san ) and ‘maximum anaerobic’ (V man) flight speeds using a published quasi-steady model. Model predictions were within 0.5 m s−1 of the empirical values for all five characteristic speeds given adequate samples. Model fidelity was cross-checked using flight speed data published for other Old and New World species.
      PubDate: 2016-09-19
      DOI: 10.1007/s13272-016-0212-5
       
  • Multiscale virtual testing: the roadmap to efficient design of composites
           for damage resistance and tolerance
    • Authors: C. S. Lopes; C. González; O. Falcó; F. Naya; J. LLorca; B. Tijs
      Abstract: Abstract This paper proposes a novel approach to the determination of the mechanical behaviour of composite materials up to failure using numerical and experimental techniques in parallel. A bottom-up multiscale virtual testing strategy is presented to take into account the physical mechanisms of deformation at different length scales on the behaviour of the composite. Starting from the microscale, the contributions of the basic constituents, microstructure and loading conditions to the mechanical response are considered in a rigorous way. This hierarchical multiscale approach describes systematically the material behaviour at different length scales from ply to laminate to component level, allowing the determination of ply properties, laminate characteristics and structural response. Additionally, this approach easily allows consideration of changes in properties of the constituents (fibre, matrices), fibre architecture or laminate lay-up and provides fast predictions of their influences on the macroscopic behaviour of composite structures. Hence, this approach constitutes a promising tool to provide significant efficiency gains in the design, testing and certification of composite aircraft structures.
      PubDate: 2016-09-16
      DOI: 10.1007/s13272-016-0210-7
       
  • Handling qualities evaluation of an automatic slung load stabilization
           system for rescue hoist operations
    • Authors: D. Nonnenmacher; M. Jones
      Abstract: Abstract The Handling Qualities (HQs) of a helicopter can be adversely affected through the presence of an externally slung load. Helicopter stability margins may be reduced, due to the additional dynamics of the load system, which can subsequently increase pilot workload, and reduce the operational envelope. An Automatic Load Damping System (ALDS) has been designed and has been successfully tested in flight. This system, alongside slung load scenarios, has been implemented within a piloted simulation in DLR’s Air Vehicle Simulator. In this article, the results from a simulated test campaign to observe the influence of the stabilization system on the vehicle HQs are presented. The system is assessed using three Mission Task Elements, modified for hoist operations. Results show that a conflict between pilot control and commanded inputs from the ALDS can cause unstable slung load oscillations and degradation in HQs in hover. However, it is shown that when the stabilization system is used only when required, both the HQs of the helicopter are conserved, and load oscillations are reduced. The results in this paper are intended to motivate future flight tests using DLR’s Active Control Technology/Flying Helicopter Simulator.
      PubDate: 2016-09-14
      DOI: 10.1007/s13272-016-0211-6
       
  • Analysis of dry-spot behavior in the pressure field of a liquid composite
           molding process
    • Authors: D. Bertling; R. Kaps; E. Mulugeta
      Abstract: Abstract Due to industrial automation of liquid composite molding processes and increasing geometrical complexity of composite components, dry-spots from flow front junctions have become increasingly difficult to avoid. The impact and behavior of voids (microscopic or small macroscopic gas entrapments) during preform impregnation is well known, but no attention is given to dry-spots (large macroscopic gas entrapments). Experiments show that formation of a dry-spot in an early stage of an injection process does not necessarily lead to scrap parts. Therefore, simulation-based predictions of dry-spots are no sufficient condition for identification of unsuitable injection strategies. In this paper, the resolution mechanisms of dry-spots under controlled process conditions are investigated and the resulting findings of fundamental formation- and dispersion-mechanisms are presented.
      PubDate: 2016-08-31
      DOI: 10.1007/s13272-016-0207-2
       
  • Fiber-reinforced polymers with integrated shape memory alloy actuation: an
           innovative actuation method for aerodynamic applications
    • Authors: M. Hübler; S. Nissle; M. Gurka; U. Breuer
      Abstract: Abstract This contribution focuses on the application potential of active fiber-reinforced polymer (FRP) structures with integrated shape memory alloy (SMA) elements for new aerodynamic functions. The advantages of hybrid SMA FRP structures are highlighted, and promising application concepts are discussed. To illustrate the applicability of the technology, the developed manufacturing, design, and control approaches are presented. Main focus is the development of a new concept for an active aerodynamic airfoil and the realization of a hardware demonstrator. Beginning with the idea of an adaptive airfoil, able to bear an application relevant down force at a relatively high deflection, the design process starts with an evaluation of different actuation concepts. An SMA-powered cantilever is a part of the profile itself. Applying the finite-element method with a suitable model for the active hybrid material, an effective selection of material and design is possible. After manufacturing and assembling of the active hybrid airfoil, a comparison of experimental results and simulation is the first proof of success. Finally, the installation of an integrated hardware setup with power source, control, and the active hybrid structure, demonstrating actuation on demand, verifies the potential and the distinct advantages of the new approach using SMA FRP structures.
      PubDate: 2016-08-30
      DOI: 10.1007/s13272-016-0209-0
       
  • Investigation of a simplified aerodynamic modelling technique for noise
           predictions using FW–H propagation
    • Authors: Jianping Yin; Berend G. van der Wall; Gunther A. Wilke
      Abstract: Abstract This paper addresses the influence of the elastic rotor blade deformation and the aerodynamic interference from the fuselage on the rotor aerodynamics, including rotor noise characteristics. A BO105 main rotor/fuselage configuration is chosen for the numerical simulations. An unsteady aerodynamic code based on free wake three-dimensional panel method (UPM) is used to account for nonlinear effects associated with the mutual interference between main rotor and fuselage. Airbus Helicopters’ (formerly: Eurocopter) rotor code (HOST) is coupled with this aerodynamic code (UPM) to account for the effect of elastic blade deformation. The effect of the fuselage is simulated using two fuselage models in aerodynamic code, (1) potential theory in the form of a panelized fuselage and (2) an analytic fuselage influence formulation derived from isolated fuselage simulation. The advantage of (2) is in its computational efficiency. The aerodynamic modelling is then coupled with an aero-acoustic post-processing tool based on the Ffowcs-Williams–Hawkings (FW–H) approach for evaluating the noise propagation to the far-field. This toolchain is then evaluated in different flight conditions to assess the usability of this approach in the design process. In descending flight, the acoustic prediction is completed at a very mature level, as the blade vortex interaction is well captured. In climb, the major noise peak is underpredicted, while the overall directivity agreement is well matched. In forward flight, due to a phase shift in the airloads prediction, parts of the loading noise directivity are not well captured. The onset of transonic effects further degrades the results obtained at the front of the rotor. For the investigated flight cases, the analytical fuselage formulation brought very similar results to the panelized fuselage model, therefore proving its worthiness for further accelerating the simulation in these flight conditions.
      PubDate: 2016-08-25
      DOI: 10.1007/s13272-016-0208-1
       
  • Impact of pulsed jet actuators on aircraft mass and fuel consumption
    • Authors: Francesco G. A. Bertels; Reinier van Dijk; Reno Elmendorp; Roelof Vos
      Abstract: Abstract Pulsed jet actuators (PJAs) are one of the candidate technologies to be integrated in Fowler flaps to increase the maximum lift coefficient of transport aircraft in the landing configuration. The total system consists of the actuators plus sensors, a piping system to supply pressurized air and a (redundant) power and communication system to provide actuator control. In this paper, it is investigated what increase in the maximum lift coefficient is required to justify the added weight and power off-takes that accompany the integration of pulsed jet actuators. This is done by making an automated design process for the overall aircraft, the piping assembly system, and the electrical wiring interconnection system. These last two sub-systems rely on KBE techniques that automate dimensioning and performance evaluation. A test case is specified that encompasses the design of a typical single-aisle mid-range aircraft with and without the PJA system installed. It is concluded that the introduction of the PJA system requires at least an increase in maximum lift coefficient of 0.2 to justify the increase in system mass and power off-takes. Furthermore, it is shown that if the maximum lift coefficient increases with 0.4, only small reductions in maximum take-off weight (−0.3 %) and operating empty weight (−0.6 %) can be expected, while the total fuel burn remains virtually constant.
      PubDate: 2016-08-11
      DOI: 10.1007/s13272-016-0201-8
       
  • Design methodology for trailing-edge high-lift mechanisms
    • Authors: David Zaccai; Francesco Bertels; Roelof Vos
      Abstract: Abstract A new methodology has been developed that integrates the preliminary wing design with trailing edge high-lift systems and accounts for three-dimensional flap kinematics. The high-lift system in the developed application includes the kinematic synthesis of four common mechanisms (dropped-hinge, four-bar, link-track and hooked-track) and a preliminary actuation architecture. The paper details how each of these mechanisms is synthesized based on a set of intuitive input requirements such as gap and overlap dimensions in landing and take-off configuration. A SimMechanics multi-body mechanism model is generated to obtain the internal loads of the mechanism and actuation torque. The mechanisms and actuating drive train are structurally sized, leading to a determination of system weight and power consumption. A weight measurement of the outboard hooked-track mechanism of a VFW-614 flap has been compared to a modeled hooked-track mechanism by using the proposed method. This resulted in a 13 % underestimation of the mechanism weight, which was attributed to modeling simplifications, sizing assumptions and a crude aerodynamic load estimation. A comparison study between the four different mechanism types to be applied on a Boeing 777 wing, shows that the method can give the designer valuable insight in the gap/overlap behavior of the flap during deployment as well as an initial estimation of the difference in required fairing size, mechanism weight, and actuation power between the four mechanisms.
      PubDate: 2016-08-04
      DOI: 10.1007/s13272-016-0202-7
       
  • Wing weight estimation in conceptual design: a method for strut-braced
           wings considering static aeroelastic effects
    • Authors: Gabriel P. Chiozzotto
      Abstract: Abstract This paper presents a method for the wing weight estimation of strut-braced wing aircraft in conceptual design. The method is simple to implement while still capturing important effects for early design estimates. Static aeroelastic loads, aeroelastic divergence and aileron reversal criteria are calculated directly with small matrices suitable for implementation in spreadsheet software. Maneuver, gust and ground cases are considered. A direct non-iterative method is used for the strut and wing internal loads calculation. The wing and strut load-carrying structures are sized with analytical box-beam equations for strength, buckling and fatigue criteria. Aluminum or composite laminates can be considered. Semi-empirical methods are presented for non-optimal mass components and the secondary structure. The aeroelastic effects and strut reaction estimations are compared for a wide range of design parameters with Nastran validating the proposed method. The weight estimations are verified with conventional aircraft data and strut-braced wing studies available in the literature, showing good accuracy. Design trade studies are presented illustrating typical applications of the method. A potential to reduce the wing mass in about 18 % or to increase the aspect ratio from 10 to 16 compared to a cantilever wing is identified.
      PubDate: 2016-08-02
      DOI: 10.1007/s13272-016-0204-5
       
  • Recent research topics in high-lift aerodynamics
    • Authors: J. Wild
      Abstract: Abstract High-lift systems are matured, robust and reliable components of a transport aircraft. Although facing nearly 100 years of history, there is an ongoing need of research in the aerodynamics of such systems due to changes in the requirements for aircraft development. Other than in former times, high-lift aerodynamics research is nowadays more incorporated into larger projects. It is, therefore, not as visible as before when dedicated high-lift projects were conducted, as e.g., the EC funded project EUROLIFT. The aim of this summary is to collect from different projects, the current challenging research topics in the area of high-lift aerodynamics. The contribution gives an overview on recent research topics addressed at the German DLR Institute of Aerodynamics and Flow Technology in collaboration with national and international partners.
      PubDate: 2016-07-30
      DOI: 10.1007/s13272-016-0206-3
       
  • An adaptive self-managing platform for cabin management systems
    • Authors: M. Riedlinger; O. Marquardt; R. Ahmadi; R. Reichel
      Abstract: In the cabin domain, the degree of changeability is an important commercial parameter. This includes customization before initial aircraft delivery as well as in-service cabin rearrangements and upgrades. This requires a highly flexible cabin management system (CMS). Today`s CMSs face this challenge with configurable system architectures offering a vast change domain, however, the change process itself is very time consuming and error-prone. To overcome this issue our approach of an Adaptive Platform will make manual configuration widely dispensable. Thereby adaptivity means that all components of the platform’s software architecture are able to adapt to any CMS instance nearly without human intervention. Most of the system knowledge needed for this purpose, e.g., topology or communication requirements, is autonomously obtained by discovery mechanisms. The adaptive software architecture contains the following: (1) a data-centric communication middleware, (2) management services clearly separated from the application and (3) plug and play mechanisms for the integration of new application software and peripheral devices. Focus of this paper is the management service which abstracts faulty resources and coordinates global system behaviour w.r.t. aircraft’s state. As a proof of concept, an adaptive CMS demonstration system was realized. We think that the proposed architecture will increase the flexibility within the lifecycle of a CMS substantially. In addition, the contained management services raise the application’s abstraction level by disburden it from any management tasks. Further work on this topic may cover evaluation of the adaptive approach for more safety critical avionic systems or incorporate certification aspects such as automated documentation and testing.
      PubDate: 2016-07-23
      DOI: 10.1007/s13272-016-0205-4
       
  • Crash concept for composite transport aircraft using mainly tensile and
           compressive absorption mechanisms
    • Authors: Paul Schatrow; Matthias Waimer
      Abstract: Abstract Current design concepts for transport aircraft aim at increasing the aircraft efficiency and performance by the introduction of advanced composite materials, such as carbon fibre reinforced plastics (CFRP). These novel transport aircraft designs may show dissimilar dynamic response behaviour due to differences in failure modes and energy absorption characteristics compared with the current transport aircraft designs made of aluminium alloys. For that reason, crash concepts are being developed to utilise the high specific energy absorption of composite materials for predefined load conditions. In the context of this paper, crash concepts for future CFRP transport aircraft were developed in which most of the kinetic energy is absorbed by tension energy absorbers integrated in the cabin and cargo floor, and by crushing energy absorbers integrated in the cabin floor support struts. The developed crash concepts define mainly parallel activation of different crash devices to achieve smooth energy absorption for different crash load scenarios. Crushing of the energy absorbers integrated in the cabin floor support struts is controlled by a novel structural design in this fuselage area. So far, this research is limited to conceptual studies performed on the basis of a generic CFRP fuselage design. Numerical simulations using the explicit finite-element (FE) code Abaqus/Explicit were performed to derive qualitative and quantitative results for an assessment of the crash concepts. A hybrid FE/macro model approach was used that combines typical FE discretisation with macro models for main failure representation. Two different crash kinematics were considered which distinguish between the failure patterns of the frame structure of the lower fuselage shell. The simulation results presented in this paper in terms of energy plots, passenger accelerations, and crash sequences identify favourable crash performance for a load scenario with fully loaded cabin and an impact velocity of 9.1 m/s (30 ft/s). Significant amount of kinetic energy could be absorbed by tension loads. Parallel activation of crash devices resulted in smooth crash kinematics with reduced trigger loads. By utilisation of the cabin floor support strut area as an energy absorption zone, sufficient energy absorption capacity could be provided even for load scenarios with increased impact energies. The results, presented in this paper, are the basis for further detailed research work on this tension crash concept.
      PubDate: 2016-07-22
      DOI: 10.1007/s13272-016-0203-6
       
  • Compressors for ultra-high-pressure-ratio aero-engines
    • Authors: R. von der Bank; S. Donnerhack; A. Rae; F. Poutriquet; A. Lundbladh; A. Antoranz; L. Tarnowski; M. Ruzicka
      Abstract: Abstract A highly efficient, robust compression system is a key part of any high-performance core engine that is to be developed for meeting future low emission requirements, i.e., for significant reductions in CO2, NOx, and other gaseous emissions. Not only does the compression system has to deliver the increased OPR demanded by the thermal cycle. It has to do so more efficiently to avoid excessive increases in cycle temperatures and weight to avoid reducing the benefit from the new cycle. This challenge is made harder, as OPR is increased up to 70:1, as core-engine size will reduce introducing greater threats to efficiency and compressor stability margin through: (1) lower Reynolds numbers that will result in higher blade losses; (2) tip and shroud/seal clearances increasing due to physical size limitations; (3) if manufacturing tolerances are maintained, blade and vane leading edges, maximum thickness, and fillets radii will be relatively larger; (4) the threat of inclement weather, deterioration, and foreign object damage (FOD) will be greater as compressors get smaller; (5) high aspect ratio blade design will be applied to limit the relative weight and length increase due to required pressure ratio increase of the compression system; (6) higher OPR compression systems will require more stability improvement features, such as VSVs, bleeds, and rotor tip treatments. This paper gives an overview of the above issues and how the FP7 integrated project LEMCOTEC is addressing them through CFD simulations, low- and high-speed rig tests, and innovative designs.
      PubDate: 2016-07-07
      DOI: 10.1007/s13272-016-0200-9
       
  • Numerical investigations of aerodynamic properties of a propeller blown
           circulation control system on a high wing aircraft
    • Authors: Dennis Keller; Ralf Rudnik
      Abstract: Abstract The contribution gives an overview over a wide range of CFD simulations, which were performed in the course of the German collaborative research center 880 to investigate the aerodynamic properties of a complete turboprop powered transport aircraft in landing configuration with a circulation control high-lift system. The main purpose of the contribution is to highlight aerodynamic and flight mechanical aspects of the integration of lift augmentation technologies into the design of a short take-off and landing aircraft concept. In this context, the influence of engine nacelles and thrust on the stall behavior and the following improvements due to the use of a nacelle strake are discussed. Furthermore, static longitudinal and lateral stability as well as the dynamic longitudinal stability are investigated. While circulation control itself has a rather small impact on the stability, the impact of engine thrust in conjunction with circulation control is considerable. In addition, the one engine inoperative case was simulated. For some flow and engine conditions, the resulting yawing moments are more than twice as high as the actual yawing moments due to asymmetric thrust.
      PubDate: 2016-06-28
      DOI: 10.1007/s13272-016-0195-2
       
  • Propeller and inflow vortex interaction: vortex response and impact on the
           propeller performance
    • Authors: Yannian Yang; Teng Zhou; Andrea Sciacchitano; Leo Veldhuis; Georg Eitelberg
      Abstract: Abstract The aerodynamic operating conditions of a propeller can include complex situations where vorticity from sources upstream can enter the propeller plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade–vortex interaction or BVI. The interaction may affect the propeller performance as well as its noise production. In the present paper, investigations of the interaction of a wing tip vortex generated by a lifting surface upstream of the rotor plane and an eight-bladed propeller are reported. Utilizing two ends of an upstream wing with non-symmetrical airfoil, the rotation of the incoming vortex could be made to co-rotate or to contra-rotate with the propeller. The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the propeller shaft. The results describe the displacement of the vortex core, as it moves through the rotor plane as well as the positive effect on the thrust and torque of the contra-rotating vortex and the opposite of it in the case of the co-rotating vortex. The current research could be applied to analyse the influence of the incoming vortex on the propeller, e.g., ground vortex, tip vortex shed from a control surface, etc.
      PubDate: 2016-06-23
      DOI: 10.1007/s13272-016-0198-z
       
  • Investigation of an automated dry fiber preforming process for an aircraft
           fuselage demonstrator using collaborating robots
    • Authors: Mona Eckardt; Andreas Buchheim; Tobias Gerngross
      Abstract: Abstract High-performance carbon fiber-reinforced plastics (CFRP) see a continuous growth of their share in structural weight. In particular, in Aerospace, this includes the production of large components, where the key issue of significant high costs remains persistent. The Center for Lightweight Production Technologies in Augsburg as a part of the German Aerospace Center (DLR) addresses this problem with solutions for process automation to increase repeatability, process robustness, and cost-efficiency. This paper presents an approach for automated preforming of large CFRP parts by means of collaborative robots. Investigations include process development for robotic handling of large-carbon fiber cut- pieces and validation on a full-scale demonstrator. The experimental verification is focused on a demonstrator geometry that represents a fuselage section of a typical short- to mid-range aircraft. The work is completed by a discussion about the challenges, solution approaches, and observations. The presented semi-automated preforming process with collaborating robots is an important intermediate step on the way to a fully automated production process for large Aerospace parts made of CFRP.
      PubDate: 2016-06-23
      DOI: 10.1007/s13272-016-0199-y
       
  • Assessment of a state-space aeroelastic rotor model for rotorcraft flight
           dynamics
    • Authors: Riccardo Gori; Jacopo Serafini; Marco Molica Colella; Massimo Gennaretti
      Abstract: Abstract The aim of the paper is the assessment of a methodology for the identification of a helicopter rotor aeroelastic operator in state-space form relating airframe motion and blade controls perturbations to corresponding hub loads, as extracted from a high-fidelity rotor aeroelastic solver. It is suited for helicopter flight dynamics stability and real-time commands response analyses, as well as for control laws synthesis.The identification method consists of a three-step process, starting with evaluation of responses to small perturbation harmonic inputs, followed by their spectral analysis and rational form approximation of corresponding transfer functions. Considering a Bo-105-type helicopter, numerical investigation is focused on: analysis of critical parameters affecting accuracy and efficiency of transfer functions identification, interpretation of the additional states introduced by rational approximation, validation of rotor finite-state aeroelastic representation.
      PubDate: 2016-06-15
      DOI: 10.1007/s13272-016-0196-1
       
  • Integration of a visibility graph based path planning method in the
           ACT/FHS rotorcraft
    • Authors: M. Zimmermann; C. König
      Abstract: Abstract This work presents recent progress at the German Aerospace Center (DLR) in landing guidance for helicopter approaches to landing sites without prior reconnaissance. During the project ALLFlight, DLRs research rotorcraft Advanced Control Technology/Flying Helicopter Simulator (ACT/FHS) has been equipped with a sensor suite including a LIDAR sensor, a forward looking RADAR, an infrared camera and a TV camera to provide sensor-based situational awareness. Using the information acquired by the LIDAR, a method for planning an initial flight path from previously unknown landing entry points to the landing point is presented. It is based on a previously developed method using a vehicle point representation, geo-referenced flight surfaces and visibility graphs. A second mode to provide re-planning capabilities in-flight is described. First results of flight tests conducted in 2013 are presented and discussed. Using the data recorded during these approaches, an improved re-planning strategy for the final approach based on so called visibility hulls is presented. This work continues recent research at DLR’s Institute of Flight Systems helicopter department for flight under degraded visual environment (DVE) for a full-scale helicopter.
      PubDate: 2016-06-13
      DOI: 10.1007/s13272-016-0197-0
       
  • Semi-empirical modeling of fuselage–rotor interference for comprehensive
           codes: influence of side-slip angle
    • Authors: Berend G. van der Wall; Jianping Yin
      Abstract: Abstract A semi-empirical and physics-based analytical formulation of the induced velocities generated by the fuselage shell of the Bo105 wind tunnel model in the volume around the rotor is derived from velocity data computed by a panel code. The reduced-order analytical model is several orders of magnitude faster than the panel code and thus is predestinated for use in comprehensive rotor codes. Angle of attacks investigated include vertical descent, shallow descent, level flight and climb to vertical ascent. Side-slip angles range from forward to quartering flight. The analytical induced velocity model can be directly used to account for the inflow at the blade elements and also allows for analytical or numerical integration of rotor wake convection to compute the associated displacements of rotor blade tip vortices travelling downstream within this velocity field. This model will be used to replace a fully panelized fuselage (and thus significantly reduce the computational effort) throughout a simulation with an aeromechanics code to account for the influence of the fuselage (e.g., in a design stage). The usage within an aerodynamics code (e.g., a panel code) reduces the panelization to the rotor blades only, leaving the computation of the fuselage-induced velocities to the model. The focus of this paper is the analytical evaluation of fuselage–rotor interference in side-slip angles on rotor trim controls, using blade element momentum theory. The results are compared to the influence of thrust-induced inflow gradients on rotor trim.
      PubDate: 2016-06-08
      DOI: 10.1007/s13272-016-0194-3
       
 
 
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