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DINAME 2017
XVII International Symposium on Dynamic Problems of Mechanics
INVESTIGATION OF THE LIMITS OF THE MODAL DAMPING ASSUMPTION FOR STRUCTURES WITH NONLINEAR LOCALIZED DAMPERS
Submission Author:
NOUREDDINE BOUHADDI , France , France
Co-Authors:
Mohamed Krifa, NOUREDDINE BOUHADDI, Najib Kacem
Presenter: NOUREDDINE BOUHADDI
doi://10.26678/ABCM.DINAME2017.DIN17-0081
Abstract
In many engineering area, quite often vibration is not desirable and the interest lies in reducing it by dissipation of energy or damping. Damping presents one of the most important physical aspects to model and estimate, since it plays a large role in determining the performance of a dynamic system and the amplitude of vibrations. The structural damping is well known and is typically responsible for a light level of damping compared to the joint damping. Damping in jointed interfaces is still not well mastered because of the complexity of the dissipation by friction, which includes nonlinear and localization effects. So, when eigenmodes are coupled with damping due to the nonlinear behaviour and the localization effects, as in the case of the most assembled structures, the Rayleigh assumption of proportional damping can lead to significant errors. The aim of this paper is the investigation of the representation assessment of the damping in a modal framework, in the case of localized dissipation. In order to quantify the effects of the nonlinear and the modal coupling on the dynamic responses, a quantification/correction method based on perturbation approach using asymptotic expansion of the frequency responses is proposed. The limitations of the proportional damping are then inspected and the correction of error estimations of modal damping due to the neglect of coupling terms is illustrated. A double-beam structure with a nonlinear interface is proposed to illustrate the validity and effectiveness of the proposed method.
Keywords
modal damping, localized dissipation, perturbation method
