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.
System identification from GVT and taxiing of an unmanned aerial vehicle - Coppotelli, G.; Grappasonni, Chiara; Arras, M.; Valyou, D.; Miller, J.T.; Marzocca, P.
The modal parameters of an aircraft structure are currently estimated from ground vibration tests (GVT). These tests are carried out on ground in order to estimate the frequency response functions first and then the modal parameters. Such estimates require one or more shakers to excite the structure together with simultaneous measurements of both the input and the output signals. Recent developments in operational modal analysis allowed such modal identification from the measurements of the output responses only, provided that the unmeasurable excitation is practically a white noise stochastic input in the frequency range of interest and is randomly exciting the...
Experimental Validation of Structural Damping Models for Tape Springs - Dewalque, Florence; Bruls, Olivier
The objective of this paper is to study the eﬀect of structural dissipation on the dynamic response of tape springs using experimentally-validated ﬁnite element models. In order to reach this goal, an experimental set-up is built. It consists of two tape springs connected to a ﬁxation support and a dummy panel. The data are collected through a force plate and a 3D motion analysis system. The post-treatment of the experimental results and a comparison with a ﬁnite element model show that the Kelvin-Voigt model gives a fair approximation of the structural damping for small oscillations, however, more advanced model should...
Bifurcation Analysis of Large-Scale Dynamical Systems Using the Harmonic Balance Method - Detroux, Thibaut; Renson, Ludovic; Masset, Luc; Kerschen, Gaëtan
The harmonic balance (HB) method has been widely used in the past few years, as a
numerical tool for the study of nonlinear industrial models. However, in its classical formulation the HB method is limited to the approximation of periodic solutions. 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 frequency response of a spacecraft and its bifurcations are studied, together with two nonlinear phenomena, namely quasiperiodic oscillations and detached resonance curves.
Numerical study of intrinsic features of isolas in a 2-dof nonlinear system - Detroux, Thibaut; Noël, Jean-Philippe; Masset, Luc; Kerschen, Gaëtan; Virgin, Lawrence N.
In the present paper, isolated response curves in a nonlinear system consisting of two masses
sliding on a horizontal guide are examined. 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. Numerical simulations are carried out to study the conditions of existence of isolated solutions, their bifurcations, their merging with the main response branch and their basins of attraction. This is achieved using tools including nonlinear normal modes, energy balance, harmonic balance-based continuation and bifurcation tracking, and global analysis.
Nonlinear ground vibration identification of an F-16 aircraft - Part 2: Parameter estimation using a frequency-domain subspace method - Dossogne, Tilàn; Noël, Jean-Philippe; Kerschen, Gaëtan; Peeters, Bart; Debille, Jan; Vaes, Mark; Schoukens, Johan
Although they are generally modelled as linear systems, aircraft structures are known to be prone to nonlinear phenomena. A specific challenge encountered with fighter aircraft, besides aeroelastic nonlinearity, is the modelling of the wing-to-payload mounting interfaces. For large amplitudes of vibration, friction and gaps may be triggered in these connections and markedly impact the dynamic behaviour of the complete structure. In this series of two papers, the nonlinear dynamics of an F-16 aircraft is investigated using rigorous methods applied to real data collected during a ground vibration test campaign. The present work focuses on the construction of an experimental mathematical...
Nonlinear ground vibration identification of an F-16 aircraft - Part 1: Fast nonparametric analysis of distortions in FRF measurements - Vaes, Mark; Schoukens, Johan; Peeters, Bart; Debille, Jan; Dossogne, Tilàn; Noël, Jean-Philippe; Kerschen, Gaëtan
Although they are generally modelled as linear systems, aircraft structures are known to be prone to nonlinear phenomena. A specific challenge encountered with fighter aircraft, besides aeroelastic nonlinearity, is the modelling of the wing-to-payload mounting interfaces. For large amplitudes of vibration, friction and gaps may be triggered in these connections and markedly impact the dynamic behaviour of the complete structure. In this series of two papers, the nonlinear dynamics of an F-16 aircraft is investigated using rigorous methods applied to real data collected during a ground vibration test campaign. The present work focuses on the detection, qualification and quantification of...
Nonlinear model updating by means of identified nonlinear normal modes - Song, Mingming; Renson, Ludovic; Noël, Jean-Philippe; Moaveni, Babak; Kerschen, Gaëtan
Modal parameters are the most common features used for linear model updating. Although the modal analysis theory does not hold for nonlinear dynamic systems, its popularity encouraged researchers to come up with an equivalent version of normal modes for nonlinear systems, i.e., nonlinear normal modes (NNMs). A nonlinear system vibrates in NNMs when all masses have periodic motions of the same period, and at any time, the position of all the masses is uniquely defined by the position of any one of them. This paper investigates the feasibility of nonlinear model updating by minimizing the difference between the model-predicted and...
A frequency-domain method for identifying nonlinear vibrating structures - Noël, Jean-Philippe; Dossogne, Tilàn; Kerschen, Gaëtan
System identification, which refers to the construction of mathematical models from experimental data, plays a key role in the design process of engineering systems. In structural dynamics, the theoretical and experimental aspects of linear system identification have been successfully addressed since the early seventies, and mature analytical, computational and testing tools have emerged. Nonlinear system identification of vibrating structures has also enjoyed significant advances during the past few years. However, the common practice in industry is to ignore nonlinearities, arguably because their analysis is still regarded as impractical. The present work describes a rigorous nonlinear generalisation in the frequency domain...