References of "Golinval, Jean-Claude"
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See detailStructural Integrity Monitoring by Vibration Measurements
Yan, Ai-Min; De Boe, Pascal; Golinval, Jean-Claude ULg

Conference given outside the academic context (2003)

This paper presents a comparative study on several approaches of structural dam-age diagnosis based on vibration meas-urements. Stochastic subspace identifica-tion method is used to identify modal pa ... [more ▼]

This paper presents a comparative study on several approaches of structural dam-age diagnosis based on vibration meas-urements. Stochastic subspace identifica-tion method is used to identify modal pa-rameters and to generate a Kalman predic-tion model, which are taken as damage-sensitive features for structural damage detection. A statistical process control technique based on principal component analysis (PCA) is also presented. An im-provement and enhancement of PCA is proposed. It is assumed that without dam-ages, structural responses should remain approximately in a hyperplane defined by the principal directions of data. Damage localization is explored with these meth-ods. As only the measured output signals are needed, the methods are convenient for on-line monitoring. The efficiency and limitation of the proposed methods are illustrated by numerical and practical ap-plications. [less ▲]

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See detailModel Updating Based on Frequency Response Functions Using A General Finite Element Code
Yan, Ai-Min; Golinval, Jean-Claude ULg

in European Journal of Mechanical and Environmental Engineering (2003), 48(3), 149-162

Model updating techniques using frequency response function (FRF) data are studied in this paper. The numerical techniques are discussed for implementation with a large commercial finite element (FE ... [more ▼]

Model updating techniques using frequency response function (FRF) data are studied in this paper. The numerical techniques are discussed for implementation with a large commercial finite element (FE ) code. System equivalent reduction expansion process is adopted to reduce the complete FE solutions onto the experimental degrees of freedom. The rank-deficiency difficulty with this method is overcome using either of two numerical techniques: diagonal perturbation and singular value decomposition. This second technique is also used in solving the updating equation. Experimental FRF data are compared with the FE solutions, and the updated model parameters are obtained via an iteration procedure. A simplified frequency domain assurance criterion is proposed to evaluate the correlation between the FE model and the measured structure at the chosen frequencies. After verifying the efficiency of the methods with several benchmark tests, the program is applied to an aeroplane model test. Some conclusions are given and remaining problems illustrated. [less ▲]

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See detailUse of Whole-Field Displacement Measurements for Model Updating of Blades
SIMON, Daniel; Golinval, Jean-Claude ULg

Conference given outside the academic context (2003)

Non-contacting measurement techniques such as modal holographic interferometry look very promising for finite element (F.E.) model updating or error localization of plate-like structures in the field of ... [more ▼]

Non-contacting measurement techniques such as modal holographic interferometry look very promising for finite element (F.E.) model updating or error localization 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 of optical techniques in order to correct FE meshing discretization errors and/or model parameter errors. The key idea developed in this paper is to calculate successively two error estimators using only measurement data. The experimental field is first used for the detection of singular regions corresponding to high deformation (or stress) 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 detailSubstructure Damage Detection by Principal Component Analysis : Application to Environmental Vibration Testing
De Boe, Pascal; Yan, Ai-Min; Golinval, Jean-Claude ULg

Conference given outside the academic context (2003)

This paper deals with the application of statistical process control techniques based on principal component analysis to vibration-based damage diagnosis of structures. It is well known that localized ... [more ▼]

This paper deals with the application of statistical process control techniques based on principal component analysis to vibration-based damage diagnosis of structures. It is well known that localized structural damages with relative small amplitude may not much affect the global modal response of the structure, at least at low frequencies. Nevertheless, it can be expected that the local dynamic behavior of the damaged structural component is significantly affected. By applying principal component analysis on the sensor time responses, it may be shown that any change of a particular sensor will affect the subspace spanned by the response of the complete sensor set. The subspace corresponding to the damaged structure can then be compared with the subspace of an initial state in order to diagnose possible damages. The problem of structural damage detection is addressed in the case of a fatigue test by means of an electro-dynamic shaker. In this example, monitoring of the structural responses is performed during a qualification test in order to detect any structural damage. [less ▲]

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See detailAuto-associative neural networks, Part II: Feacture extraction for non-linear model updating
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in 8th Internationale Conference on Recent Advances in Structural Dynamics, Southampton, 2003 (2003)

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See detailValidating structural models in non-linear dynamics
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in 6ème congrès national de Mécanique Th. et App., Gent, 2003 (2003)

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See detailAuto-associantive neural networks, Part I: Replacement of missing sensor values,
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in 8th Internationale Conference on Recent Advances in Structural Dynamics, Southampton, 2003 (2003)

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See detailModeling of the influence of electric forces on mechanical structures
Rochus, Véronique ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

Conference (2003)

This paper is a summary concerning the modeling of the strong electro-mechanical coupling appearing in micro-electro-mechanical systems (MEMS). These systems are very small devices (typical size of a few ... [more ▼]

This paper is a summary concerning the modeling 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 finite element method is used to discretize simultaneously the electrostatic and mechanical fields. The formulation is consistently derived from variational principles based on the electro-mechanical free energy. In classical weakly coupled formulations staggered iteration is used between the electrostatic and the mechanical domain. Therefore, in those approaches, linear stiffness is evaluated by finite differences and equilibrium is reached typically by relaxation techniques. The strong coupling formulation presented here allows to derive exact tangent matrices of the electro-mechanical system. Thus it allows to compute non-linear equilibrium positions using Newton- Raphson type iterations combined with adaptive meshing in case of large displacements. Furthermore, the tangent matrix obtained in the method considered in this paper greatly simplifies the computation of vibration modes and frequencies of the coupled system around equilibrium configurations. The non-linear variation of frequencies with respect to voltage and stiffness can then be investigated until pull-in appears. In order to illustrate the effectiveness of the proposed formulation numerical results are shown first for the reference problem of a simple flexible cap acitor, then for the model of a micro-bridge. [less ▲]

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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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