Contrôle des oscillations libres horizontales d'un câble par un amortisseur non linéaire : théorie, expériences et robustesse

Ce travail s'intéresse à la problématique du contrôle des oscillations libres horizontales d'un câble par un amortisseur à non linéarité cubique. Il retrace une démarche complète : l'analyse du comportement du système réel initial à contrôler, le dimensionnement théorique de l'amortisseur, les essais de mise en évidence du bon fonctionnement du prototype et de ses différents comportements. Il s'agit également de tester la robustesse du dispositif en faisant varier la rigidité du couplage

Contrôle passif d'un mode de torsion de véhicule via des absorbeurs non linéaires

Des absorbeurs dynamiques non linéaires sont conçus pour atténuer les vibrations de trépidation d'un mode de torsion de caisse d'un véhicule. Le dimensionnement analytique est effectué en régime libre ou forcé sur un modèle condensé. Une validation est menée en insérant le modèle de l'absorbeur sur le modèle numérique complet du véhicule. Ce travail est mené via une collaboration industrielle et ADYNO (projet ANR)

Vibration mitigation of a bridge cable using a nonlinear energy sink: design and experiment

This work deals with the design and experiment of a cubic nonlinear energy sink (NES) for horizontal vibration mitigation of a bridge cable. Modal analysis of horizontal linear modes of the cable is experimentally performed using accelerometers and displacement sensors. A theoretical simplified 2-dof model of the coupled cable-NES system is used to analytically design the NES by mean of multi-time scale systems behaviours and detection its invariant manifold, equilibrium and singular points which stand for periodic and strongly modulated regimes, respectively. Numerical integration is used to confirm the efficiency of the designed NES for the system under step release excitation. Then, the prototype system is built using geometrical cubic nonlinearity as the potential of the NES. Efficiency of the prototype system for mitigation of horizontal vibrations of the cable under for step release and forced excitations is experimentally demonstrated

Control of vertical oscillations of a cable by a piecewise linear absorber

International audienceDesign tools for fabrication of nonlinear (nonsmooth) passive absorbers for controlling vertical modes of taut cables are presented. The design takes into account the effects of the gravity and activation of the nonlinear absorber. In detail, the slow invariant manifold of the system is tuned which lead to design of the absorber. The paper is followed by several numerical and experimental results showing the efficiency of such nonsmooth absorbers in controlling targeted vertical modes of cables

Vibration mitigation of a bridge cable using a nonlinear energy sink: design and experiment

This work deals with the design and experiment of a cubic nonlinear energy sink (NES) for horizontal vibration mitigation of a bridge cable. Modal analysis of horizontal linear modes of the cable is experimentally performed using accelerometers and displacement sensors. A theoretical simplified 2-dof model of the coupled cable-NES system is used to analytically design the NES by mean of multi-time scale systems behaviours and detection its invariant manifold, equilibrium and singular points which stand for periodic and strongly modulated regimes, respectively. Numerical integration is used to confirm the efficiency of the designed NES for the system under step release excitation. Then, the prototype system is built using geometrical cubic nonlinearity as the potential of the NES. Efficiency of the prototype system for mitigation of horizontal vibrations of the cable under for step release and forced excitations is experimentally demonstrated

Analysis of the 1:1 resonant energy exchanges between coupled oscillators with rheologies

International audienceThe paper is composed of three main parts: The first part presents a two-degree-of-freedom coupled oscillators with rheology. One of the oscillators is intended to be the main structure, and the second one is a nonlinear energy sink. The rheology of the system is represented via a set of internal variables that are governed by either differential inclusions or differential equations or direct algebraic relations between system variables. A step-by-step methodology is explained to trace system behaviors around a 1:1 resonance at different timescales. Invariant of the system at fast timescale is detected, while possible periodic and strongly modulated regimes around its invariant are traced at slow time scales. The second part of the paper considers a set of several degree-of-freedom main oscillators which are coupled to several nonlinear energy sinks. The overall system can house several rheologies. Explained methodology of the first part is expanded to this general case for tracing system responses at different time scales around 1:1 resonances. The third part of the paper presents two practical examples: The proposed methodology is used to detect invariants of systems and their equilibrium and singular points. This methodology provides some tools for designing equilibrium and singular points, i.e., periodic and strongly modulated regimes which lead to the design of nonlinear energy sinks for passively controlling and/or energy harvesting of the main oscillators

Multi-scale energy exchanges between an elasto-plasticoscillator and a light nonsmooth system with externalpre-stress

International audienceVibratory energy exchanges between twocoupled oscillators is studied: the main elasto-plasticoscillator is coupled to a nonlinear energy sink(NES)with nonsmooth potential. Both oscillators are underpre-stressing terms. Two different methods are implementedfor tracing system behaviours: (i) the timeevent-driven technique which builds exact solutions ofgoverning equations of the system phase by phase and(ii) the multi-scale method which traces system behavioursat different scales of time. It detects invariant ofthe system at fast timescale and equilibrium/singularpoints at slow timescales. The pre-stressing terms producea more complex shape for the invariant, whiledetected dynamics at slow timescale let us have controlat the behaviour of the system during its quasi-steadystateregime(s) which leads to have analytical designtools for tuning parameters of nonlinear energy sink according to design purposes (passive control and/orenergy harvesting)