References of "Golinval, Jean-Claude"
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See detail"European Cost action F3 on structural dynamics. WG3: identification of non-linear systems.Activities and Results"
Golinval, Jean-Claude ULg; Kerschen, Gaëtan ULg; Lenaerts, V. et al

in International Conference on Noise and Vibration Engineering, Leuven, 2002 (2002, September)

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See detailOn the exploitation of chaos to build reduced-order models
Kerschen, Gaëtan ULg; Feeny, B. F.; Golinval, Jean-Claude ULg

in International Conference on Noise and Vibration Engineering, Leuven, 2002 (2002, September)

The present study focuses on the model reduction of non-linear systems. The proper orthogonal decomposition is exploited to compute eigenmodes from time series of displacement. These eigenmodes, called ... [more ▼]

The present study focuses on the model reduction of non-linear systems. The proper orthogonal decomposition is exploited to compute eigenmodes from time series of displacement. These eigenmodes, called the proper orthogonal modes, are optimal with respect to energy content and are used to build a low-dimensional model of the non-linear system. For this purpose, the proper orthogonal modes obtained from a chaotic orbit are considered. Indeed, such an orbit is assumed to cover the phase space more uniformly. It is shown that the modes for this particular behaviour are more representative of the system dynamics than any other set of modes extracted from a non-chaotic response. This is applied to a buckled beam with two permanent magnets and the reduced-order model is validated using both qualitative and quantitative comparisons. [less ▲]

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See detailAn Adaptation of the Newmark Scheme for the Integrated Simulation of Mechatronic Systems
Bruls, Olivier ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

in Proceeding of 6th Int. Conf. on Motion and Vibration Control (MOVIC) (2002, August)

A methodology is developed to simulate flexible multibody systems subject to the action of a digital control system. The mechanical model is built in the formalism of flexible multibody dynamics using the ... [more ▼]

A methodology is developed to simulate flexible multibody systems subject to the action of a digital control system. The mechanical model is built in the formalism of flexible multibody dynamics using the Finite Element Method. At the begining of each sampling period, the model of the control system is used to compute the control forces and torques applied to the mechanism. A second-order system with a direct velocity feedback controller is considered to study the performances of the method. A modification of the classical Newmark algorithm yields outstanding improvements in the results quality. [less ▲]

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See detailNon-linear generalization of principal component analysis: From a global to a local approach
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in Journal of Sound & Vibration (2002), 254(5), 867-876

Principal component analysis (PCA), also known as proper orthogonal decomposition or Karhunen-Loeve transform, is commonly used to reduce the dimensionality of a data set with a large number of ... [more ▼]

Principal component analysis (PCA), also known as proper orthogonal decomposition or Karhunen-Loeve transform, is commonly used to reduce the dimensionality of a data set with a large number of interdependent variables. PCA is the optimal linear transformation with respect to minimizing the mean square reconstruction error but it only considers second-order statistics. If the data have non-linear dependencies, an important issue is to develop a technique which takes higher order statistics into account and which can eliminate dependencies not removed by PCA. Recognizing the shortcomings of PCA, researchers in the field of statistics and neural networks have developed non-linear extensions of PCA. The purpose of this paper is to present a non-linear generalization of PCA, called VQPCA. This algorithm builds local linear models by combining PCA with clustering of the input space. This paper concludes by observing from two illustrative examples that VQPCA is potentially a more effective tool than conventional PCA. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailFeature extraction for non-linear model updating
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in International Conference on Structural Dynamics Modelling, Funchal, 2002 (2002, June)

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See detailSimulation of an Active Control System in a Hot-Dip Galvanizing Line
Bruls, Olivier ULg; Golinval, Jean-Claude ULg

in Preprints of the NATO Advanced Study Institute on Virtual Nonlinear Multibody Systems (2002, June)

This paper concerns the modeling and the integrated numerical simulation of a flexible mechanism subject to the action of a digital control system. A general method is proposed, based on the formalism of ... [more ▼]

This paper concerns the modeling and the integrated numerical simulation of a flexible mechanism subject to the action of a digital control system. A general method is proposed, based on the formalism of flexible multibody systems (MBS) using the Finite Element Method (FEM). Nonlinear effects in the mechanical structure or in the control system can be taken into account. The numerical simulation tool is applied to design an active control system in a hot-dip galvanizing line, which aims at reducing the vibrations of the steel strip. [less ▲]

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See detailFinite Element Analysis of the Electro-Mechanical Coupling in MEMS
Rochus, Véronique ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

Conference given outside the academic context (2002)

This paper concerns the modelling of the strong electro-mechanical coupling appearing in micro-electro-mechanical systems (MEMS). These systems are very small devices (typical size of a few microns), in ... [more ▼]

This paper concerns the modelling of the strong electro-mechanical coupling appearing in micro-electro-mechanical systems (MEMS). These systems are very small devices (typical size of a few microns), in which electric phenomena as well as mechanical and dynamical phenomena exist. The coupling between the electric and mechanical fields induce non-linear terms in the dynamic equilibrium equations of these microscopic structures so that instability may occur. In this paper, the finite element method (FEM) is used to perform modal analysis around non-linear equilibrium positions, taking into account large displacements. [less ▲]

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See detailIntegrated simulation of mechanical structures and their control system
Bruls, Olivier ULg; De Boe, Pascal; Duysinx, Pierre ULg et al

in Proc. of the 2nd Int. Conf. on Advanced Computational Methods in Engineering (ACOMEN) (2002, May)

This paper concerns the modeling and the integrated numerical simulation of flexible mechanisms subject to the action of a digital control system. A general method is proposed, based on the formalism of ... [more ▼]

This paper concerns the modeling and the integrated numerical simulation of flexible mechanisms subject to the action of a digital control system. A general method is proposed, based on the formalism of flexible multibody systems (MBS) using the Finite Element Method (FEM). Nonlinear e ects in the mechanical structure or in the control system can be taken into account. The numerical simulation tool is applied to design an active control system in a hot-dip galvanizing line, which aims at reducing the vibrations of the steel strip. [less ▲]

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See detailActive Control of the Steel Strip in a Hot-Dip Galvanizing Line
Bruls, Olivier ULg; Golinval, Jean-Claude ULg

Conference (2002, March)

This paper concerns the design of an active control system for a hot dip galvanizing line. The control system aims at reducing the vibrations of the steel strip in order to improve the quality of the ... [more ▼]

This paper concerns the design of an active control system for a hot dip galvanizing line. The control system aims at reducing the vibrations of the steel strip in order to improve the quality of the product. The mechanical structure is quite flexible and many vibration modes need to be controlled. The actuators and the sensors are collocated and the control law is a direct velocity feedback, which doesn't require any model of the plant. This control law adds damping on all the vibration modes and it guarantees the stability of the system. The position of the actuators is chosen to maximize the controllability and the observability. The relevance of this strategy is discussed. The natural frequencies of the mechanical system are evaluated using the Finite Element Method. In this particular example, it was found that the frequencies of the flexion vibration modes almost match the frequencies of the torsion modes. The corresponding pole/zero pattern leads to very small root loci where the damping increment is strongly limited. A simulation of the closed loop system is required to evaluate the performance of the active control and to choose the feedback gain. The time-domain evolution of the mechanical structure is computed using the Finite Element Method and an implicit integration scheme. Assuming that the control system is digital and neglecting the dynamics of the actuators, the control system is introduced into the mechanical simulation as a users' routine called at each sampling time of the digital controller. This quite general approach allows to deal with nonlinear eff ects either in the mechanical structure or in the control system, what opens new perspectives in integrated simulation of controlled flexible mechanisms. The simulation shows that a single actuator is not able to control the whole steel strip. Even if the gain increases, the controlled point becomes quickly a fixed point, and the vibration of the rest of the structure is not significantly attenuated. At least three actuators are necessary to get the expected performance. [less ▲]

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See detailFrequency domain approaches for the identification of an experimental beam with a local nonlinearity
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in 20th International Modal Analysis Conference, Los Angeles, 2002 (2002, February)

Two approaches for the identification of multi-degree-of-freedom non-linear systems in the frequency domain have recently been introduced, i.e., the conditioned reverse path (CRP) method and the non ... [more ▼]

Two approaches for the identification of multi-degree-of-freedom non-linear systems in the frequency domain have recently been introduced, i.e., the conditioned reverse path (CRP) method and the non-linear identification through feedback of the outputs (NIFO) method. The key idea of these methods is to eliminate the distortions caused by the presence of non-linearities in frequency response functions. In this paper, the theoretical background of the CRP and NIFO methods is briefly recalled. Then, the ability of these techniques to identify the behaviour of an experimental cantilever beam with a local geometrical non-linearity is tested. The results obtained with both methods are compared and discussed. [less ▲]

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See detailPhysical interpretation of the proper orthogonal modes using the singular value decomposition
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in Journal of Sound & Vibration (2002), 249(5), 849-865

Proper orthogonal decomposition is a statistical pattern analysis technique for finding the dominant structures, called the proper orthogonal modes, in an ensemble of spatially distributed data. While the ... [more ▼]

Proper orthogonal decomposition is a statistical pattern analysis technique for finding the dominant structures, called the proper orthogonal modes, in an ensemble of spatially distributed data. While the proper orthogonal modes are obtained through a statistical formulation, they can be physically interpreted in the field of structural dynamics. The purpose of this paper is thus to provide some insights into the physical interpretation of the proper orthogonal modes using the singular value decomposition. (C) 2002 Academic Press. [less ▲]

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See detailCOST Action F3 on Structural Dynamics: Benchmarks for Structural Health Monitoring
Worden, K.; Molina, F.; Pascual, R. et al

Conference given outside the academic context (2002)

This paper is concerned with the results from the COST Action F3 Working Group Two benchmarking exercise in Structural Health Monitoring. Data from two large-scale structures were modelled for the ... [more ▼]

This paper is concerned with the results from the COST Action F3 Working Group Two benchmarking exercise in Structural Health Monitoring. Data from two large-scale structures were modelled for the purposes of damage detection, location and quantification. Several analysis papers have been submitted for a special issue of Mechanical Systems and Signal Processing and the conclusions of each are summarised here, together with more general conclusions arising from the concerted effort. [less ▲]

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See detailAccelerated Fatigue Testing Methodology of Luminaires on Electro-Dynamic Shaker
Marin, Frédéric; Golinval, Jean-Claude ULg; Marville, Christian

Conference given outside the academic context (2002)

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See detailFinite Element Model Updating of Plate-like Structures Using Modal Holographic Measurement Field
Simon, Daniel; Golinval, Jean-Claude ULg

Conference given outside the academic context (2002)

Optical measurement techniques are very promising for finite element (F.E.) model updating or error localisation of plate-like structures in the field of structural dynamics. The purpose of this work is ... [more ▼]

Optical measurement techniques are very promising for finite element (F.E.) model updating or error localisation of plate-like structures in the field of structural dynamics. The purpose of this work is to investigate a way to better exploit the high spatial resolution inherent to these techniques in order to correct FE mesh discretisation errors and/or model parameter errors. An important assumption in F.E. model error detection is first to consider the initial mesh as sufficiently fine to well represent the measured (displacement or stress) field. In the case of model updating, the adjustment of the model is performed by minimising the difference between the outputs of the model and the exact solution with respect to design parameters. In the case of FE mesh adaptation, the exact solution has to be estimated whereas in the case of model parameter errors, the reference solution is assumed to be the measured one. The idea developed in this paper is to take advantage of the high spatial resolution offered by optical techniques to calculate successively two error estimators using only measurements. The experimental field is first used for the detection of singular regions corresponding to high gradients. This estimator indicates the regions where a mesh refinement is required. Thus a second estimator is calculated and used for parameter error detection. [less ▲]

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See detailA Robust FRF-based Technique for Model Updating
Pascual, Rodrigo; Razeto, Mario; Golinval, Jean-Claude ULg et al

Conference given outside the academic context (2002)

Frequency Response Functions (FRFs) residues have been widely used in time to update Finite Element models. Major reasons for this is that FRFs are very sensitive to damping properties at resonance peaks ... [more ▼]

Frequency Response Functions (FRFs) residues have been widely used in time to update Finite Element models. Major reasons for this is that FRFs are very sensitive to damping properties at resonance peaks, local modes influence is included and no modal analysis is required. Nevertheless, it is well known that due to their nature, the frequency responses may change its order of magnitude very rapidly for small parameter or frequency changes. This situation may cause serious discontinuities in the topology of the objective function, causing the updating strategy to diverge or to find a local non-physical minimum. A primary tool for the correlation of FRFs is the Frequency Domain Assurance Criterion. This technique introduces the concept of frequency shift between the frequency response shapes of a reference model (the experimental structure) and a perturbed model (an initial non-updated FE model). Such a concept opens the way for using residues at different frequencies. For instance, in reference the residue is composed by point FRFs at anti-resonances. This paper introduces a general FRF-based model-updating technique, which is focused in using stable residues during the interactive optimization procedure. A benchmark case from the Cost F3 action is used to assess the goodness of the method compared to other well known methods. [less ▲]

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See detailModeling of Electro-mechanical coupling in MEMS
Rochus, Véronique ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

Scientific conference (2002)

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See detailExperimental identification of a non-linear beam, conditionned reverse path method
Kerschen, Gaëtan ULg; Lenaerts, Vincent; Golinval, Jean-Claude ULg

in International Conference on Structural Systems Identification, Kassel, 2001 (2001, September)

A new spectral approach for identification of multi-degree-of-freedom nonlinear systems, called the conditioned reverse path method, has recently been introduced. The key idea of this method is to ... [more ▼]

A new spectral approach for identification of multi-degree-of-freedom nonlinear systems, called the conditioned reverse path method, has recently been introduced. The key idea of this method is to eliminate the distortions caused by the presence of non-linearities in frequency response functions. Conditioned frequency responses are then computed and yield the underlying linear properties without influence of non-linearities. The non-linear coefficient is estimated in a second step. The aim of the paper is twofold. Firstly, the conditioned reverse path method is described in details together with the spectral conditioning techniques. Secondly, the ability of this technique to identify the behaviour of an experimental cantilever beam with a geometrical non-linearity is tested. [less ▲]

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See detailApplication of ARMAV models to identification and damage detection of mechanical and civil engineering structures
Bodeux, Jean-Bernard; Golinval, Jean-Claude ULg

in Smart Materials & Structures (2001), 10(3), 479-489

In this paper, the application of auto-regressive moving average vector models to system identification and damage detection is investigated. These parametric models have already been applied for the ... [more ▼]

In this paper, the application of auto-regressive moving average vector models to system identification and damage detection is investigated. These parametric models have already been applied for the analysis of multiple input-output systems under ambient excitation. Their main advantage consists in the capability of extracting modal parameters from the recorded time signals, without the requirement of excitation measurement. The excitation is supposed to be a stationary Gaussian white noise. The method also allows the estimation of modal parameter uncertainties. On the basis of these uncertainties, a statistically based damage detection scheme is performed and it becomes possible to assess whether changes of modal parameters are caused by, e.g. some damage or simply by estimation inaccuracies. The paper reports first an example of identification and damage detection applied to a simulated system under random excitation. The `Steel-Quake' benchmark proposed in the framework of COST Action F3 `Structural Dynamics' is also analysed. This structure was defined by the Joint Research Centre in Ispra (Italy) to test steel building performance during earthquakes. The proposed method gives an excellent identification of frequencies and mode shapes, while damping ratios are estimated with less accuracy. [less ▲]

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See detailProper orthogonal decomposition for model updating of non-linear mechanical systems
Lenaerts, V.; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in Mechanical Systems & Signal Processing (2001), 15(1)

Proper orthogonal decomposition (POD), also known as Karhunen}Loeve (K}L) decomposition, is emerging as a useful experimental tool in dynamics and vibrations. The POD is a means of extracting spatial ... [more ▼]

Proper orthogonal decomposition (POD), also known as Karhunen}Loeve (K}L) decomposition, is emerging as a useful experimental tool in dynamics and vibrations. The POD is a means of extracting spatial information from a set of time-series data available on a domain. The use of (K}L) transform is of great help in non-linear settings where traditional linear techniques such as modal-testing and power-spectrum analyses cannot be applied. These decomposition can be used as an orthogonal basis for e$cient representation of the ensemble. The POM have been interpreted mainly as empirical system modes and the application of POD to measured displacements of a discrete structure with a known mass matrix leads to an estimation of the normal modes. We investigate the use of the proper orthogonal modes of displacements for the identi"cation of parameters of non-linear dynamical structures with an optimisation procedure based on the di!erence between the experimental and simulated POM. A numerical example of a beam with a local non-linear component will illustrate the method. (C) 2001 Academic Press [less ▲]

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See detailTheoretical and experimental identification of a non-linear beam
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg; Worden, K.

in Journal of Sound & Vibration (2001), 244

The identi"cation of the dynamic characteristics of linear systems is now widely used and interest in non-linear systems has increased. The objective of this paper is to demonstrate the performance of the ... [more ▼]

The identi"cation of the dynamic characteristics of linear systems is now widely used and interest in non-linear systems has increased. The objective of this paper is to demonstrate the performance of the restoring force surface method as far as the identi"cation of non-linear systems is concerned. The vibrations of a clamped beam are investigated for two di!erent kinds of non-linearity. Firstly, the beam shows a non-linear behaviour characterized by a piecewise linear sti!ness and secondly, the non-linearity comes from a bilinear sti!ness. Both numerical and experimental results are presented. (C) 2001 Academic Press [less ▲]

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