References of "Kerschen, Gaëtan"
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See detailModal Analysis of a Nonlinear Periodic Structure with Cyclic Symmetry
Georgiades, Fostios; Peeters, Maxime ULg; Kerschen, Gaëtan ULg et al

in AIAA Journal (2009), 47

The objective of this paper is to examine nonlinear normal modes and their bifurcations in cyclic periodic structures. The nonlinear normal modes are computed using a numerical technique that combines ... [more ▼]

The objective of this paper is to examine nonlinear normal modes and their bifurcations in cyclic periodic structures. The nonlinear normal modes are computed using a numerical technique that combines shooting and pseudoarclength continuation. Unlike perturbation techniques, the resulting algorithm can investigate strongly nonlinear regimes of motion. This study reveals that modal interactions may occur without necessarily having commensurate natural frequencies in the underlying linear system. In addition, a countable infinity of such modal Q2 interactions are shown to exist in the system. [less ▲]

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See detailNonlinear normal modes, Part 2: Toward a pratical computation using numerical continuation techniques
Peeters, Maxime ULg; Viguié, Régis ULg; Sérandour, Guillaume ULg et al

in Mechanical Systems & Signal Processing (2009), 23

The conceptofnonlinearnormalmodes(NNMs)isdiscussedinthepresentpaperandits companion,PartI.OnereasonofthestilllimiteduseofNNMsinstructuraldynamicsis that theircomputationisoftenregardedasimpractical ... [more ▼]

The conceptofnonlinearnormalmodes(NNMs)isdiscussedinthepresentpaperandits companion,PartI.OnereasonofthestilllimiteduseofNNMsinstructuraldynamicsis that theircomputationisoftenregardedasimpractical.However,whenresortingto numericalalgorithms,weshowthattheNNMcomputationispossiblewithlimited implementationeffort,whichpavesthewaytoapracticalmethodfordeterminingthe NNMsofnonlinearmechanicalsystems.Theproposedalgorithmreliesontwomain techniques,namelyashootingprocedureandamethodforthecontinuationofNNM motions. Thealgorithmisdemonstratedusingfourdifferentmechanicalsystems,a weakly andastronglynonlineartwo-degree-of-freedomsystem,asimplifieddiscrete modelofanonlinearbladeddiskandanonlinearcantileverbeamdiscretizedbythefinite elementmethod. [less ▲]

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See detailUsing passive nonlinear targeted energy transfer to stabilize drill-stringsystems
Viguié, Régis ULg; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg et al

in Mechanical Systems & Signal Processing (2009), 23

Torsional vibrations of drill strings used in drilling oil and gas wells arises from a complex interaction of the dynamics of the drilling structure with speed-dependent effective rock-cutting forces ... [more ▼]

Torsional vibrations of drill strings used in drilling oil and gas wells arises from a complex interaction of the dynamics of the drilling structure with speed-dependent effective rock-cutting forces. These forces are often difficult to model, and contribute substantially to the instability problems of controlling the drilling operation so as to produce steady cutting. In this work we show how nonlinear passive targeted energy transfer to a lightweight attachment can be used to passively control these instabilities. This is performed by means of a nonlinear energy sink (NES), a lightweight attachment which has been shown to be effective in reducing or even completely eliminating self-excited motions in aeroelastic and other systems. The NES is a completely passive, inherently broadband vibration absorber capable of attracting and dissipating vibrational energy from the primary structure to which it is attached, in this case a nonlinear discontinuous model of a drill-string system. In this paper we describe a prototypical drill string-NES system, briefly discuss some of the analytical and computational tools suitable for its analysis, and then concentrate on mathematical results on the efficacy of the NES in this application and their physical interpretation. [less ▲]

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See detailDesign procedure of a nonlinear vibration absorber using bifurcation analysis: application to a drill-string system
Viguié, Régis ULg; Kerschen, Gaëtan ULg

in Euromech 503, Nonlinear Normal Modes, Dimension Reduction and Localization in Vibrating Systems, Frascati, 2009 (2009)

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See detailDetection and quantification of non-linear dynamic behaviour of space structures
Hot, A.; Cogan, S.; Foltete, E. et al

in 11th European Conference on Spacecraft Structures, Materials and Mechanical Testing, Toulouse, 2009 (2009)

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See detailDesign procedure of a nonlinear vibration absorber using bifurcation analysis : application to the drill-string system
Viguié, Régis ULg; Kerschen, Gaëtan ULg

in ASME International Design Engineering Technical Conferences, San Diego, 2009 (2009)

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See detailExploration of nonlinear shunting strategies as effective vibration absorbers
Viguié, Régis ULg; Kerschen, Gaëtan ULg; Ruzzene, M.

in Smart Str. and Mat. & Nondestructive Eval. and Health Monitoring, San Diego, 2009 (2009)

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See detailOn modal interactions in strongly nonlinear systems
Peeters, Maxime ULg; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in Euromech 503, Nonlinear Normal Modes, Dimension Reduction and Localization in Vibrating Systems, Frascati, 2009 (2009)

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See detailModal testing of non-linear vibrating structures
Peeters, Maxime ULg; Kerschen, Gaëtan ULg

in 11th European Conference on Spacecraft Structures, Materials and Mechanical Testing, Toulouse, 2009 (2009)

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See detailModal testing of nonlinear vibrating structures based on a nonlinear extension of force appropriation
Peeters, Maxime ULg; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in ASME International Design Engineering Technical Conferences, San Diego, 2009 (2009)

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See detailDimensionality Reducion using Linear and Nonlinear Transformations
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in Boller, C. (Ed.) Encyclopedia of Structural Health Monitoring (2009)

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See detailUsing passive nonlinear targeted energy transfer to stabilize drill-stringsystems
Viguié, Régis ULg; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg et al

in International Colloquium on Non-Linear Dynamics of Deep Drill-String Systems, Liège, 2009 (2009)

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See detailDesign Procedure of a Nonlinear Vibration Absorber Using Bifurcation Analysis
Viguié, Régis ULg; Kerschen, Gaëtan ULg

in 27th International Modal Analysis Conference, Orlando, 2009 (2009)

A nonlinear energy sink (NES) is characterized by its ability to passively realize targeted energy transfer as well as multimodal damping. This latter feature seems to make this device very well suited ... [more ▼]

A nonlinear energy sink (NES) is characterized by its ability to passively realize targeted energy transfer as well as multimodal damping. This latter feature seems to make this device very well suited for reducing the vibration level of MDOF linear structures. The perspective of dealing with MDOF linear primary structures requires the development of an efficient NES design procedure. This paper poses the basis of such a procedure based upon the bifurcation analysis of a system composed of a linear oscillator coupled to a NES, using the software MatCont. [less ▲]

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See detailSpur Gear Vibration Mitigation by Means of Energy Pumping
Scagliarini, Giorgio; Viguié, Régis ULg; Kerschen, Gaëtan ULg et al

in 27th International Modal Analysis Conference, Orlando, 2009 (2009)

The dynamic behaviour of a spur gear pair can be studied in terms of transmission error considering a single degree of freedom system. Thus, a mechanical system exhibiting combined parametric excitation ... [more ▼]

The dynamic behaviour of a spur gear pair can be studied in terms of transmission error considering a single degree of freedom system. Thus, a mechanical system exhibiting combined parametric excitation and clearance type nonlinearity is examined by means of numerical integrations and continuation methods in an effort to explain its complex behaviour, as it is commonly observed in the steady state forced response of rotating machines. The specific case of a preloaded mechanical oscillator having a periodically time varying stiffness function and subject to a symmetric backlash condition is considered. Even if such an oscillator represents the simplest model able to analyze a single spur gear pair, it exhibits a complex dynamic scenario, namely jumps, superharmonics, subharmonics resonances and dynamic bifurcations. In order to reduce the vibration of the system, a nonlinear absorber is applied. Unlike common linear and weakly nonlinear systems, systems with strongly nonlinear elements are able to react efficiently on the amplitude characteristics of the external forcing in a wide range of frequencies. A strongly and essentially nonlinear, lightweight, with cubic stiffness oscillator is then attached to the main nonlinear system under periodic parametric forcing and the feasibility of a possible application of this nonlinear energy sink (NES) for vibration absorption and mitigation is checked. [less ▲]

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See detailModal analysis of a nonlinear structure with cyclic symmetry
Peeters, Maxime ULg; Viguié, Régis ULg; Kerschen, Gaëtan ULg et al

in 27th International Modal Analysis Conference, Orlando, 2009 (2009)

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See detailAPPLYING L. MANEVITCH’S COMPLEXIFICATION – AVERAGING METHOD TO ANALYZE CONDITIONS FOR OPTIMAL TARGETED ENERGY TRANSFER IN COUPLED OSCILLATORS WITH ESSENTIAL STIFFNESS NONLINEARITY
Sapsis, Themistoklis; Quinn, D. Dane; Gendelman, Oleg et al

in International Conference on Nonlinear Phenomena in Polymer Solids and Low-Dimensional Systems. Moscou, 2008 (2008, July)

We study targeted energy transfer (TET) [1] from a linear damped oscillator (LO) to a light attachment with essential stiffness nonlinearity, caused by 1:1 transient resonance capture (TRC). First, we ... [more ▼]

We study targeted energy transfer (TET) [1] from a linear damped oscillator (LO) to a light attachment with essential stiffness nonlinearity, caused by 1:1 transient resonance capture (TRC). First, we study the underlying Hamiltonian dynamics and show that for sufficiently weak damping, the nonlinear damped transitions of the system are strongly influenced by the underlying topological structure of periodic and quasiperiodic orbits of the hamiltonian system. Then, we formulate conditions that lead to effective or even optimal TET from the linear system to the nonlinear attachment. Direct analytical treatment of the governing strongly nonlinear damped equations of motion is performed by applying L. Manevitch’s complexification – averaging (CX-A) method [2] to perform slow-fast partition of the transient responses, and analytically model the dynamics in the region of optimal TET. This analysis determines the characteristic time scales of the dynamics that influence the capacity of the nonlinear attachment to passively absorb and locally dissipate broadband energy from the linear oscillator in an optimal fashion. [less ▲]

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See detailSUPPRESSION OF AEROELASTIC INSTABILITIES BY BROADBAND PASSIVE TARGETED ENERGY TRANSFERS
Lee, Young S.; McFarland, D. Michael; Vakakis, Alexander F. et al

in Sixth EUROMECH Nonlinear Dynamics Conference, Saint Petersbourg, 2008 (2008, July)

We study passive and nonlinear targeted energy transfers induced by transient resonant interactions between an essentially nonlinear attachment and an in-flow rigid wing model. We show that it is feasible ... [more ▼]

We study passive and nonlinear targeted energy transfers induced by transient resonant interactions between an essentially nonlinear attachment and an in-flow rigid wing model. We show that it is feasible to partially or even completely suppress aeroelastic instabilities in the wing (limit cycle oscillations-LCOs) by passively transferring broadband vibration energy from the wing to the attachment in a one-way irreversible fashion. We study the nonlinear dynamical mechanisms that govern TET and show that they are series of transient or sustained resonance captures in different resonance manifolds of the dynamics. Aeroelastic instability suppression is performed by partially or completely eliminating the triggering mechanism for aeroelastic instability. Through numerical parametric studies we identify three main mechanisms for suppressing aeroelastic instability, and investigate them in detail, both numerically by Empirical Mode decomposition (EMD), and analytically by slow/fast partitions of the transient dynamics. [less ▲]

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See detailNonlinear modal analysis and energy localization in a bladed disk assembly
Georgiades, Fotios; Peeters, Maxime ULg; Kerschen, Gaëtan ULg et al

in ASME Turbo Expo 2008: Power for Land, Sea and Air, Berlin, 2008 (2008, June)

The objective of this study is to carry out modal analysis of nonlinear periodic structures using nonlinear normal modes (NNMs). The NNMs are computed numerically with a method developed in [18] that is ... [more ▼]

The objective of this study is to carry out modal analysis of nonlinear periodic structures using nonlinear normal modes (NNMs). The NNMs are computed numerically with a method developed in [18] that is using a combination of two techniques: a shooting procedureand a method for the continuation of periodic motion. The proposed methodology is applied to a simplified model of a perfectly cyclic bladed disk assembly with 30 sectors. The analysis shows that the considered model structure features NNMs characterized by strong energy localization in a few sectors. This feature has no linear counterpart, and its occurrence is associated with the frequencyenergy dependence of nonlinear oscillations. [less ▲]

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See detailPassive non linear TET and its application to vibration absorption: a review
Lee, Y. S.; Vakakis, Alexander F.; Bergman, L. A. et al

in Proceedings of the Institution of Mechanical Engineers - Part K - Journal of Multi-body Dynamics (2008), 222

This review paper discusses recent efforts to passively move unwanted energy from a primary structure to a local essentially non-linear attachment (termed a non-linear energy sink) by utilizing targeted ... [more ▼]

This review paper discusses recent efforts to passively move unwanted energy from a primary structure to a local essentially non-linear attachment (termed a non-linear energy sink) by utilizing targeted energy transfer (TET) (or non-linear energy pumping). First, fundamental theoretical aspects of TET will be discussed, including the essentially non-linear governing dynamical mechanisms for TET. Then, results of experimental studies that validate the TET phenomenon will be presented. Finally, some current engineering applications of TET will be discussed. The concept of TET may be regarded as contrary to current common engineering practise, which generally views non-linearities in engineering systems as either unwanted or, at most, as small perturbations of linear behaviour. Essentially non-linear stiffness elements are intentionally introduced in the design that give rise to new dynamical phenomena that are very beneficial to the design objectives and have no counterparts in linear theory. Care, of course, is taken to avoid some of the unwanted dynamic effects that such elements may introduce, such as chaotic responses or other responses that are contrary to the design objectives. [less ▲]

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See detailToward a fundamental understanding of the Hilbert-Huang Transform in nonlinear dynamics
Kerschen, Gaëtan ULg; Vakakis, Alexander F.; Lee, Y. S. et al

in Journal of Vibration & Control (2008)

The Hilbert–Huang transform(HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental components through what has been called the empirical mode ... [more ▼]

The Hilbert–Huang transform(HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental components through what has been called the empirical mode decomposition (EMD). The HHT has been utilized extensively despite the absence of a serious analytical foundation, as it provides a concise basis for the analysis of strongly nonlinear systems. In this paper, an attempt is made to provide the missing theoretical link, showing the relationship between the EMD and the slow-flow equations of a system. The slow-flow reduced-order model is established by performing a partition between slow and fast dynamics using the complexification-averaging technique in order to derive a dynamical system described by slowly-varying amplitudes and phases. These slow-flow variables can also be extracted directly from the experimental measurements using the Hilbert transform coupled with the EMD. The comparison between the experimental and analytical results forms the basis of a novel nonlinear system identification method, termed the slow-flow model identification (SFMI) method. Through numerical and experimental application examples, we demonstrate that the proposed method is effective for characterization and parameter estimation of multi-degree-of-freedom nonlinear systems. [less ▲]

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