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ORBi Open Repository and Bibliography (193,805 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 720

1. Experimental demonstration of a 3D-printed nonlinear tuned vibration absorber - Grappasonni, Chiara; Habib, Giuseppe; Detroux, Thibaut; Kerschen, Gaëtan
Engineering structures are designed to be lighter and more flexible, hence reducing the extent of application of linear dynamic models. Concurrently, vibration mitigation is required for enhancing the performance, comfort or safety in real-life applications. Passive linear vibration absorbers are purpose-built, often designed using Den Hartog's equal-peak strategy. However, nonlinear systems are known to exhibit frequency-energy-dependent oscillations which linear absorbers cannot effectively damp out. In this context, the paper introduces a new nonlinear tuned vibration absorber (NLTVA) whose nonlinear functional form is tailored according to the frequency-energy dependence of the nonlinear primary structure. The NLTVA design aims at ensuring equal...

2. Internal Resonance and Stall-Flutter in a pitch-Flap Wing in the Wind-Tunnel - Verstraelen, Edouard; Kerschen, Gaëtan; Dimitriadis, Grigorios
Peer reviewed

3. Experimental nonlinear identification of an aircraft with bolted connections - De Filippis, Giovanni; Noël, Jean-Philippe; Kerschen, Gaëtan; Soria, Leonardo; Stephan, Cyrille
Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling of the mounting interfaces between aircraft subcomponents. Indeed, for large amplitudes of vibration, such interfaces may loosen and, in turn, trigger complex mechanisms such as friction and clearances. In this context, the present work intends to investigate the nonlinear dynamics of the Morane–Saulnier Paris aircraft, accessible at ONERA. This aircraft possesses multiple bolted connections between two external fuel tanks and wing tips. The objective of the paper is specifically to...

4. Experimental modal analysis of nonlinear structures using broadband data - Noël, Jean-Philippe; Renson, Ludovic; Grappasonni, Chiara; Kerschen, Gaëtan
The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements collected under broadband forcing. The use of such a type of forcing signal allows to excite multiple NNMs simultaneously and, in turn, to save testing time. A two-step methodology integrating nonlinear system identification and numerical continuation of periodic solutions is proposed for the extraction of the individual NNMs from broadband input and output data. It is demonstrated using a numerical cantilever beam possessing a cubic nonlinearity at its free end. The proposed...

5. The Harmonic Balance Method for Bifurcation Analysis of Nonlinear Mechanical Systems - Detroux, Thibaut; Renson, Ludovic; Masset, Luc; Kerschen, Gaëtan
Because nowadays structural engineers are willing to use or at least understand nonlinearities instead of simply avoiding them, there is a need for numerical tools performing analysis of nonlinear large-scale structures. Among these techniques, the harmonic balance (HB) method is certainly one of the most commonly used to study finite element models with reasonably complex nonlinearities. However, in its classical formulation the HB method is limited to the approximation of periodic solutions. For this reason, the present paper proposes to extend the method to the detection and tracking of codimension-1 bifurcations in the system parameters space. As an application, the...

6. Piezoelectric vibration damping using resonant shunt circuits: an exact solution - Soltani, Payam; Kerschen, Gaëtan; Tondeau, Gilles; Deraemaeker, Arnaud
Peer reviewed

7. Comparison of off-axis TMA and FMA telescopes optimized over different fields of view: applications to Earth observation - Clermont, Lionel; Stockman, Yvan; Dierckx, Wouter; Loicq, Jerôme
TMA, or three mirror anastigmats, have already been used successfully for various space missions. In the frame of earth observation, ProbaV satellite uses 3 TMAs to cover a total 102.4° field-of-view; ground sampling distance is about 100m at the center of field-of view and 370m at the edge. For future earth observation missions, the goal would be to reach 100m spatial resolution all over the 102.4° FOV. This would require to up-scale optical specifications, thus increasing geometrical aberrations. FMA, or four mirror anastigmats, could thus be a good candidate for future missions, as a fourth mirror would allow better correction...

8. Complex dynamics of a nonlinear aerospace structure: numerical continuation and normal modes - Renson, Ludovic; Noël, Jean-Philippe; Kerschen, Gaëtan
Peer reviewed

9. A rigorous phase separation method for testing nonlinear structures - Noël, Jean-Philippe; Renson, Ludovic; Grappasonni, Chiara; Kerschen, Gaëtan
The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements collected under broadband forcing. The use of such a type of forcing signal allows to excite multiple NNMs simultaneously and, in turn, to save testing time. A two-step methodology integrating nonlinear system identification and numerical continuation of periodic solutions is proposed for the extraction of the individual NNMs from broadband input and output data. It is demonstrated using a numerical cantilever beam possessing a cubic nonlinearity at its free end. The proposed...

10. Experimental and numerical study of the flight of geese - Dimitriadis, Grigorios; Gardiner, James; Tickle, Peter; Codd, Jonathan; Nudds, Robert
Peer reviewed

11. Probabilistic Assessment of Lifetime of Low-Earth-Orbit Spacecraft: Uncertainty Propagation and Sensitivity Analysis - Dell'Elce, Lamberto; Kerschen, Gaëtan
Peer reviewed

12. Modular bimorph mirrors for adaptive optics - Rodrigues, Goncalo; Bastaits, Renaud; Roose, Stéphane; Stockman, Yvan; Gebhart, Sylvia; Schoenecker, Andreas; Villon, Pierre
Peer reviewed

13. Large deployable telescopes—also for lm-wavelengths? - Baier, Horst; Datashvili, Leri; Endler, Stephan; Roose, Stéphane; Stockman, Yvan
Peer reviewed

14. Empirical modelling of the bifurcation behaviour of a bridge deck undergoing across-wind galloping - Andrianne, Thomas; Dimitriadis, Grigorios
Peer reviewed

15. Importance of structural damping in the dynamic analysis of compliant deployable structures - Dewalque, Florence; Rochus, Pierre; Bruls, Olivier
Compliant mechanisms such as tape springs are often used on satellites to deploy appendices, e.g. solar panels, antennas, telescopes and solar sails. Their main advantage comes from the fact that their motion results from the elastic deformation of structural components, unlike usual hinges or prismatic joints, the motion of which is dictated by contact surfaces. No actuators or external energy sources are required and the deployment is purely passive, which appears as a decisive feature for the design of low-cost missions with small satellites or cubesats. The mechanical behaviour of a tape spring is intrinsically complex and nonlinear involving buckling,...

16. Space radiation parameters for EUI and the Sun Sensor of Solar Orbiter, ESIO and JUDE instruments - Rossi, Laurence; Jacques, Lionel; Halain, Jean-Philippe; Grodent, Denis; Renotte, Etienne; Thibert, Tanguy
This paper presents predictions of space radiation parameters for four space instruments performed by the Centre Spatial de Liège (ULg – Belgium); EUI, the Extreme Ultra-violet Instrument, on-board the Solar Orbiter platform; ESIO, Extreme-UV solar Imager for Operations, and JUDE, the Jupiter system Ultraviolet Dynamics Experiment, which was proposed for the JUICE platform. For Solar Orbiter platform, the radiation environment is defined by ESA environmental specification and the determination of the parameters is done through ray-trace analyses inside the EUI instrument. For ESIO instrument, the radiation environment of the geostationary orbit is defined through simulations of the trapped particles flux, the energetic...

17. Solar simulation test up to 13 solar constants for the thermal balance of the Solar Orbiter EUI instrument - Rossi, Laurence; zhukova, Maria; Jacques, Lionel; Halain, Jean-Philippe; Hellin, Marie-Laure; Jamotton, Pierre; Renotte, Etienne; Rochus, Pierre; Liébecq, Sylvie; Mazzoli, Alexandra
Solar Orbiter EUI instrument was submitted to a high solar flux to correlate the thermal model of the instrument. EUI, the Extreme Ultraviolet Imager, is developed by a European consortium led by the Centre Spatial de Liège for the Solar Orbiter ESA M-class mission. The solar flux that it shall have to withstand will be as high as 13 solar constants when the spacecraft reaches its 0.28AU perihelion. It is essential to verify the thermal design of the instrument, especially the heat evacuation property and to assess the thermo-mechanical behavior of the instrument when submitted to high thermal load. Therefore, a thermal...

18. An efficient flamelet-based combustion model for compressible flows - Saghafian, Amirreza; Terrapon, Vincent; Pitsch, Heinz
Peer reviewed

19. Grey-box identification of a non-linear solar array structure using cubic splines - Noël, Jean-Philippe; Kerschen, Gaëtan; Foltête, Emmanuel; Cogan, Scott
Peer reviewed

20. Modal identification of time-varying systems using Hilbert transform and signal decomposition - Bertha, Mathieu; Golinval, Jean-Claude
The present work investigates modal identification of time-varying dynamical systems by exploiting the Hilbert transform. The proposed method, initially based on the Hilbert Vibration Decomposition (HVD) method, first identifies the instantaneous frequencies of the system. Their corresponding components and modal deflection shapes are then extracted from a set of dynamic responses of the system. The proposed method is first presented and then is illustrated on an experimental set-up. The system under investigation is a recurrent experiment in the field of time-varying systems consisting in a beam travelled by a non-negligible mass while excited by a random external force. The results...

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