ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

4aSA1. Parameter estimation for fuzzy structures. A result concerning vibrations in the low-frequency range.

Christian Soize

Structures Dept., ONERA, BP 72, 92322 Chatillon Cedex, France

In the field of structural vibrations, the structural complexity can be induced by ``secondary'' mechanical subsystems attached to the ``master'' structure or by ``local eigenmodes'' of some continuum elastic subelements of the master structure; these local eigenmodes induce a structural complexity when the model of these subelements can only restitute the elastostatic behavior but not its elastodynamic response. Within this context, a model is presented of the apparent vibration damping of the master structure due to the vibrations of the structural complexity. This vibration-damping model is deduced from the theory of fuzzy structures that was previously developed by the author. Presently, this model uses only the mean part of the probabilistic fuzzy law of the fuzzy substructure. A model of the generalized damping matrix deduced from the model of the structural complexity, is explicitly constructed. This generalized damping matrix depends on parameters related to the fuzzy substructure. Problems related to the model parameters estimation are studied. Finally, an example is presented and allows the theory to be validated.