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H. Ecker, F. Dohnal, H. Springer:
"Enhanced Damping of a Beam Structure by Parametric Excitation";
Vortrag: Fifth EUROMECH Nonlinear Dynamics Conference, Eindhoven; 07.08.2005 - 12.08.2005; in: "Proceedings ENOC-2005", D. H. van Campen, M.D. Lazurko, W.P.J.M. van den Oever (Hrg.); (2005), ISBN: 90-386-2667-3; Paper-Nr. 22-271, 10 S.

In this numerical study new findings on parametric resonances of beam structures are presented. A uniform cantilever beam under the influence of a timeperiodic axial force is investigated. The beam structure is discretized by a Finite Element approach. The linearized equations of motion describing the planar vibrations of the beam structure lead to a system with time-periodic stiffness coefficients. The stability of the system is investigated by a numerical method based on Floquet´s theorem. Numerical simulation is employed to calculate time series of the transient beam deflections. It is demonstrated, that the parametrically excited beam structure exhibits enhanced damping properties, when excited by a non-resonant parametric combination resonance frequency. A certain level of the forcing amplitude has to be exceeded to achieve the damping effect. Upon exceeding this value, the additional artificial damping provided to the structure is significant and works best for suppression of vibrations of the first vibrational mode of the structure.

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