ORBi Open Repository and Bibliography
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.
The optical blocking filter for the ATHENA wide field imager: ongoing activities towards the conceptual design - Barbera, M.; Branduardi-Raymont, G.; Collura, A.; Comastri, A.; Eder, J.; Kamisiński, T.; Lo Cicero, U.; Meidinger, N.; Mineo, T.; Molendi, S.; Parodi, G.; Pilch, A.; Piro, L.; Rataj, M.; Rauw, Gregor; Sciortino, L.; Sciortino, S.; Wawer, P.
ATHENA is the L2 mission selected by ESA to pursue the science theme "Hot and Energetic Universe" (launch scheduled in 2028). One of the key instruments of ATHENA is the Wide Field Imager (WFI) which will provide imaging in the 0.1-15 keV band over a 40'x40' large field of view, together with spectrally and time-resolved photon counting. The WFI camera, based on arrays of DEPFET active pixel sensors, is also sensitive to UV/Vis photons. Optically generated electron-hole pairs may degrade the spectral resolution as well as change the energy scale by introducing a signal offset. For this reason, the use...
Experimental study of isolated response curves in a two-degree-of-freedom nonlinear system - Detroux, Thibaut; Noël, Jean-Philippe; Kerschen, Gaëtan; Virgin, Lawrence N.
In the present paper, the observation and characterization of isolated response curves (IRCs) are experimentally reported in the case of a nonlinear system consisting of two masses sliding on an horizontal guide. Transverse springs are attached to one mass to provide the nonlinear restoring force, and a harmonic motion of the complete system is imposed by prescribing the displacement of their supports. The existence of an IRC is related to a 3:1 internal resonance between the two modes of the system. The observed IRC is studied in detached and merged conditions using swept-sine excitations and system perturbations.
Obtaining nonlinear frequency responses from broadband testing - Gourc, Etienne; Grappasonni, Chiara; Noël, Jean-Philippe; Detroux, Thibaut; Kerschen, Gaëtan
The objective of the paper is to obtain the frequency response curves of nonlinear mechanical systems from broadband testing. The proposed approach consists in coupling an identification method with a continuation method. Specifically, the frequency-domain nonlinear subspace identification (FNSI) method is first used to derive an experimental model of the structure in state space from broadband measurements. The harmonic balance method coupled with arclength continuation then utilizes this experimental model to compute the frequency response curves of the system. The method is demonstrated using a numerical example.
Experimental Study of Isolated Response Curves on a 2-Degree-of-Freedom Nonlinear System - Detroux, Thibaut; Noël, Jean-Philippe; Kerschen, Gaëtan; Virgin, Lawrence N.
In the present paper, the experimental realization of isolated response curves (IRCs) in the vicinity of internal resonances is examined. The nonlinear set-up consists of two masses sliding on a horizontal guide, with transverse springs attached to one mass to provide the nonlinear restoring force. A harmonic motion of the complete system is imposed by prescribing the displacement of their supports. Free responses of the system are analyzed to show the presence of internal resonances, and IRCs are revealed through sine-sweep excitations carried out at different energy levels. Both merged and detached scenarii are studied, in order to assess the...
RAPPORT SCIENTIFIQUE & TECHNIQUE FINAL - Projet BLUM – RW 6800 - Lecomte-Beckers, Jacqueline; Tchuindjang, Jérôme Tchoufack; Paydas, Hakan
Le projet BluM® s’inscrit dans la continuité du projet Blisk. En effet les trade-off architecturaux du projet Blisk plan Marshall ont conduit Techspace Aero à se tourner vers le développement d’un concept encore plus porteur en terme de masse et plus ambitieux en terme de défi technologique que les blisk « classiques ». Il s’agit du développement de composant rotorique multi étage monobloc, d’où l’acronyme BluM® pour Bladed Drum.
Sur les turboréacteurs actuels, les compresseurs basse pression comportent un tambour, dont le fût se compose de glissières circulaires dans lesquelles on introduit les aubes. Le projet apporte des solutions nouvelles...
PIV-based estimation of unsteady loads on a flat plate at high angle of attack using momentum equation approaches - Guissart, Amandine; Bernal, Luis; Dimitriadis, Grigorios; Terrapon, Vincent
The direct measurement of loads with force balance can become challenging when the forces are small or when the body is moving. An alternative is the use of Particle Image Velocimetry (PIV) velocity fields to indirectly obtain the aerodynamic coefficients. This can be done by the use of control volume approaches which lead to the integration of velocities, and other fields deriving from them, on a contour surrounding the studied body and its supporting surface.
This work exposes and discusses results obtained with two different methods: the direct use of the integral formulation of the Navier-Stokes equations and the so-called Noca's...