VIBRATION DAMPING IN LOW-FREQUENCY RANGE DUE TO STRUCTURAL COMPLEXITY- A MODEL-BASED ON THE THEORY OF FUZZY STRUCTURES AND MODEL PARAMETERS ESTIMATION

For some large structures with internal structural complexity, the mod eling of the ''secondary'' mechanical subsystems attached to the ''mas ter'' structure allows the vibration predictions to be improved in the low frequency range for which the master structure has a modal respon se. Within this context, we present a model of the vibration damping d ue to the vibrations of mechanical subsystems constituting the interna l structural complexity. This vibration-damping model is deduced from the theory of fuzzy structures which was previously developed by the a uthor. Presently, this model uses only the mean part of the probabilis tic fuzzy law of the fuzzy substructure. A model of the generalized da mping matrix which then includes a modeling of the internal structural complexity is explicitly constructed. This generalized damping matrix depends on parameters related to the fuzzy substructure. Problems rel ated to the model parameters estimation are studied. Finally, an examp le is presented and allows the theory to be validated.