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ORBi Open Repository and Bibliography (260.650 recursos)

In may 2007, the ULg's Administrative Board (joined in June 2007 by the FUSAGx) decided to create an institutional repository and defined a strong institutional self-archiving policy to increase the visibility, accessibility and impact of the University's publications (Board's decision). This decision led to the official launch, in November 2008, of the ORBi platform including both the Academic Bibliography and the Institutional Repository of the Wallonia-Europe University Academy.

Engineering, computing & technology => Aerospace & aeronautics engineering

Mostrando recursos 1 - 20 de 938

  1. Experimental Passive Flutter Mitigation Using a Linear Tuned Vibrations Absorber

    Verstraelen, Edouard; Habib, Giuseppe; Kerschen, Gaëtan; Dimitriadis, Grigorios
    The current drive for increased efficiency in aeronautic structures such as aircraft, wind turbine blades and helicopter blades often leads to weight reduction. A consequence of this tendency can be increased flexibility, which in turn can lead to unfavourable aeroelastic phenomena involving large amplitude oscillations and nonlinear effects such as geometric hardening and stall flutter. Vibration mitigation is one of the approaches currently under study for avoiding these phenomena. In the present work, passive vibration mitigation is applied to an experimental aeroelastic system by means of a linear tuned vibration absorber. The aeroelastic apparatus is a pitch and flap wing that...

  2. Induced Drag Calculations with the Unsteady Vortex Lattice Method for Cambered Wings

    Lambert, Thomas; Dimitriadis, Grigorios
    Peer reviewed

  3. ASPIICS: an externally occulted coronagraph for PROBA-3.Design evolution.

    Renotte, Etienne; Carmen Baston, Elena; Bemporad, Alessandro; Capobianco, Gerardo; Cernica, Ileana; Darakchiev, Radoslav; Denis, François; Desselle, Richard; de Vos, Lieve; Fineschi, Silvano; Focardi, Mauro; Górski, Tomasz; Graczyk, Rafał; Halain, Jean-Philippe; Hermans, Aline; Jackson, Carl; Kintziger, Christian; Kosiec, Jacek; Kranitis, Nektarios; Landini, Federico; Lédl, Vít; Massone, Giuseppe; Mazzoli, Alexandra; Melich, Radek; Mollet, Dominique; Mosdorf, Michał; Nicolini, Gianalfredo; Nicula, Bogdan; Oleański, Piotr; Palau, Marie-Catherine; Pancrazzi, Maurizio; Paschalis, Antonis; Peresty, Radek; Plesseria, Jean-Yves; Rataj, Miroslaw; Romoli, Marco; Thizy, Cédric; Thome, Michel; Tsinganos, Kanaris; Wodnicki, Ryszard; Walczak, Tomasz; Zhukov, Andrei
    PROBA-3 is a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future ESA missions. PROBA-3 will fly ASPIICS (Association de Satellites pour l’Imagerie et l’Interferométrie de la Couronne Solaire) as primary payload, which makes use of the formation flying technique to form a giant coronagraph capable of producing a nearly perfect eclipse allowing to observe the sun corona closer to the rim than ever before. The coronagraph is distributed over two satellites flying in formation (approx. 150m apart). The so called Coronagraph Satellite carries the camera and the so called Occulter Satellite carries the...

  4. The EUI instrument on board the Solar Orbiter mission: from breadboard and prototypes to instrument model validation

    Halain, Jean-Philippe; Rochus, Pierre; Renotte, Etienne; Appourchaux, T.; Berghmans, D.; Harra, L.; Schühle, U.; Schmutz, W.; Auchère, F.; Zhukov, A.; Dumesnil, C.; Delmotte, F.; Kennedy, T.; Mercier, R.; Pfiffner, D.; Rossi, Laurence; Tandy, J.; BenMoussa, A.; Smith, Phyllis
    The Solar Orbiter mission will explore the connection between the Sun and its heliosphere, taking advantage of an orbit approaching the Sun at 0.28 AU. As part of this mission, the Extreme Ultraviolet Imager (EUI) will provide full-sun and high-resolution image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. To achieve the required scientific performances under the challenging constraints of the Solar Orbiter mission it was required to further develop existing technologies. As part of this development, and of its maturation of technology readiness, a set of breadboard and prototypes of critical subsystems...

  5. Mean-Field-Homogenization-based stochastic multiscale methods for composite materials

    Wu, Ling; Lucas, Vincent; Adam, Laurent; Noels, Ludovic
    When considering a homogenization-based multiscale approach, at each integration-point of the macro-structure, the material properties are obtained from the resolution of a micro-scale boundary value problem. At the micro-level, the macro-point is viewed as the center of a Representative Volume Element (RVE). However, to be representative, the micro-volume-element should have a size much bigger than the micro-structure size. For composite materials which suffer from a large property and geometrical dispersion, either this requires RVE of sizes which cannot usually be obtained numerically, or simply the structural properties exhibit a scatter at the macro-scale. In both cases, the representativity of the...

  6. Failure multiscale simulations of composite laminates based on a non-local mean-field damage-enhanced homogenization

    Wu, Ling; Adam, Laurent; Doghri, Issam; Noels, Ludovic
    A multiscale method is developed to study the failure of carbon fiber reinforced composites. In order to capture the intra-laminar failure, a non-local mean-field homogenization (MFH) method accounting for the damage evolution of the matrix phase of the composite material [1] is considered. In that formulation, an incremental-secant MFH approach is used to account for the elastic unloading of the fibers during the strain softening of the matrix. In order to avoid the strain/damage localization caused by the matrix material softening, an implicit non-local method [2] was reformulated to account for the composite material anisotropy. As a result, accurate predictions...

  7. Influence of the inter‐stage coupling flexibility on the dynamics of multi‐stage rotors

    Nyssen, Florence; Golinval, Jean-Claude
    Peer reviewed

  8. Nonlinear analysis of compliant mechanisms: application to tape springs

    Dewalque, Florence; Bruls, Olivier
    Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for more details.

  9. Passive flutter suppression using a nonlinear tuned vibration absorber

    Verstraelen, Edouard; Gourc, Etienne; Kerschen, Gaëtan; Dimitriadis, Grigorios
    A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was turning the initial super-critical bifurcation into a sub-critical one. This work shows numerically that adding a nonlinear restoring force to the absorber can restore the su- percritical behaviour of the bifurcation and further reduce the post-instability limit cycle amplitude.

  10. Efficient and Robust Automatic Augmented Lagrangian Algorithm for Solving Frictional Contact Problems - Application to Wire Drawing Process

    Wautelet, Gaëtan; Papeleux, Luc; Ponthot, Jean-Philippe

  11. SWAP and LYRA: space weather from a small spacecraft

    Defise, Jean-Marc; Lecat, Jean-Hervé; Stockman, Yvan; Rochus, Pierre; Mazy, Emmanuel; Denis, François; Halain, Jean-Philippe; Rossi, Laurence; Thibert, Tanguy; Berghmans, D.; others
    Two scientific instruments for Sun observations are being developed to be part of the payload of the ESA's second microsatellite, Proba-II (Project for On-board Autonomy). PROBA-2 is scheduled for launch in early 2007, on a low earth orbit. Like Proba-1, in orbit since October 2001, Proba-2 is a 100-kilogram class spacecraft. PROBA-II will demonstrate new advanced technologies on its scientific payload but also on new platform subsystems such as star tracker, digital Sun sensor, cool gas generator, solar array concentrator, Li-Ion Battery, new central processor, ... This paper is dedicated to the solar payload, comprising the Sun Watcher using Active Pixel...

  12. Straylight tests for the Heliospheric imagers of STEREO

    Defise, Jean-Marc; Halain, Jean-Philippe; Mazy, Emmanuel; Rochus, Pierre
    The design of the Heliospheric Imager (HI) of the NASA Solar TErrestrial Relations Observatory (STEREO) is based on an optical baffle system. It will reject the solar disk light with attenuation of the order of 10-13 and 10-15, and let two separate camera systems (HI-1 and HI-2) measure the extremely faint solar coronal mass ejections. A multi-vane diffractive system has been optimized to achieve the lower requirement (10-13 for HI-1) and is combined with a secondary baffling system to reach the 10-15 rejection performance in the second camera system (HI-2). The theoretical performances of the baffling systems will be experimentally verified...

  13. Design and performances of the heliospheric imager for the STEREO mission

    Mazy, Emmanuel; Halain, Jean-Philippe; Defise, Jean-Marc; Ronchain, Philippe; Howard, Russell A; Moses, J. D.; Eyles, Chris; Harrison, Richard
    The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO spacecrafts to be launched in 2006. Located on two different orbits, the two HI instruments will provide stereographic images of solar coronal plasma and coronal mass ejections (CME) over a wide field of view (~90°), ranging from 13 to 330 solar radii (R[SUB]0[/SUB]). These observations complete the 15 R[SUB]0[/SUB] field of view of the solar corona obtained with the other SECCHI instruments (2 coronagraphs and an EUV imager). The HI instrument is a combination of 2 refractive optical systems with 2 different multi-vanes baffle...

  14. MAGRITTE optomechanical design and mirror manufacturing

    Mazy, Emmanuel; Defise, Jean-Marc; Halain, Jean-Philippe; Rochus, Pierre; Rossi, Laurence; Mercier, Raymond; Ravet, Marie-Francoise; Delmotte, Franck; Idir, Mourad
    The MAGRITTE telescopes are part of the SHARPP instrument suite, part of the Solar Dynamics Observatory (SDO), a NASA spacecraft to be launched in a geostationnary orbit in 2007. The MAGRITTE instrument package will provide high resolution images of the solar corona at high temporal frequency simultaneously in 5 EUV and in Ly-alpha narrow bandpasses. The 1.4 R[SUB]0[/SUB] MAGRITTE common field of view complements the other SHARPP instruments, as well as its spectral coverage with 6 narrow bandpasses located within the 19.5 to 120 nm interval. The key challenges of the MAGRITTE instrument are a high angular resolution (0.66 arcsec/pixel)...

  15. The extreme UV imager telescope on-board the Solar Orbiter mission: overview of phase C and D

    Halain, Jean-Philippe; Rochus, Pierre; Renotte, Etienne; Hermans, Aline; Jacques, Lionel; Auchère, Frédéric; Berghmans, David; Harra, Lionel; Schühle, Udo; Schmutz, Werner
    The Solar Orbiter mission is composed of ten scientific instruments dedicated to the observation of the Sun’s atmosphere and its heliosphere, taking advantage of an out-of ecliptic orbit and at perihelion reaching a proximity close to 0.28 A.U. On board Solar Orbiter, the Extreme Ultraviolet Imager (EUI) will provide full-Sun image sequences of the solar corona in the extreme ultraviolet (17.1 nm and 30.4 nm), and high-resolution image sequences of the solar disk in the extreme ultraviolet (17.1 nm) and in the vacuum ultraviolet (121.6 nm). The EUI concept uses heritage from previous similar extreme ultraviolet instrument. Additional constraints from the specific...

  16. Performance of diamond detectors for VUV applications

    BenMoussa, A.; Theissen, A.; Scholze, F.; Hochedez, J. F.; Schühle, U.; Schmutz, W.; Haenen, K.; Stockman, Yvan; Soltani, A.; McMullin, D.; Vest, R. E.; Kroth, U.; Laubis, C.; Richter, M.; Mortet, V.; Gissot, S.; Delouille, V.; Dominique, M.; Koller, S.; Halain, Jean-Philippe; Remes, Z.; Petersen, R.; D'Olieslaeger, M.; Defise, Jean-Marc
    Peer reviewed

  17. The solar orbiter imager (SoloHI) instrument for the Solar Orbiter mission

    Howard, R.; Vourlidas, A.; Korendyke, C.; Plunkett, S.; Carter, T.; Wang, D.; Rich, N.; McMullin, D.; Lynch, Sean; Thurn, Adam; Clifford, G.; Socker, D.; Thernisien, A.; Chua, D.; Linton, M.; Keller, D.; Janesick, J.; Tower, J.; Grygon, M.; Hagood, R.; Bast, W.; Liewer, P.; De Jong, E.; Velli, M.; Mikic, Z.; Bothmer, V.; Rochus, Pierre; Halain, Jean-Philippe; Lamy, P.
    The SoloHI instrument for the ESA/NASA Solar Orbiter mission will track density fluctuations in the inner heliosphere, by observing visible sunlight scattered by electrons in the solar wind. Fluctuations are associated with dynamic events such as coronal mass ejections, but also with the “quiescent” solar wind. SoloHI will provide the crucial link between the low corona observations from the Solar Orbiter instruments and the in-situ measurements on Solar Orbiter and the Solar Probe Plus missions. The instrument is a visible-light telescope, based on the SECCHI/Heliospheric Imager (HI) currently flying on the STEREO mission. In this concept, a series of baffles...

  18. MAGRITTE / SPECTRE : the Solar Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory

    Rochus, Pierre; Defise, Jean-Marc; Halain, Jean-Philippe; Mazy, Emmanuel; Jamar, Claude; Clette, France; Cugnon, P.; Berghmans, D.; Hochedez, J. F.; Delaboudiniere, J. P.; Artzner, G.; Auchere, F.; Mercier, ROSANNA; Ravet, M. F.; Delmotte, Marc; Idir, M.; Fineschi, S.; Antonucci, E.; Harrison, R. A.; Howard, R. A.; Moses, J. D.; Newmark, J. S.
    The Solar Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory will characterize the dynamical evolution of the solar plasma from the chromosphere to the corona, and will follow the connection of plasma dynamics with magnetic activity throughout the solar atmosphere. The AIA consists of 7 high resolution imaging telescopes in the following spectral bandpasses: 1215 \x8F Ly-a, 304 \x8F He II, 629 \x8F OV, 465 \x8F Ne VII, 195 \x8F Fe XII (includes Fe XXIV), 284 \x8F Fe XV, and 335 \x8F Fe XVI. The telescopes are grouped by instrumental approach: the Magritte Filtergraphs (R. Magritte, famous 20th Century...

  19. LYRA, a solar UV radiometer on PROBA2

    Hochedez; Schmutz, W.; Stockman, Yvan; Schuhle, U.; BenMoussa, A.; Koller, S.; Haenen, K.; Berghmans, D.; Defise, Jean-Marc; Halain, Jean-Philippe; Theissen, A.; Delouille, V.; Slemzin, V.; Gillotay, D.; Fussen, D.; Dominique, M.; Vanhellemont, F.; McMullin, D.; Kretzschmar, M.; Mitrofanov, A.; Nicula, B.; Wauters, L.; Rochus, Pierre
    Peer reviewed

  20. PROBA II payload: a Belgian mini space weather observatory

    Rochus, Pierre; Defise, Jean-Marc; Lecat, Jean-Hervé; Stockman, Yvan; Franco, P.; Gillis, Jean-Marie; Mazy, Emmanuel; Halain, Jean-Philippe; Rossi, Laurence; Thibert, Tanguy

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