Strategies for identification of reduced vibro-acoustic models from experimental modal analysis

In this paper, some strategies are proposed for the identification of reduced physical vibro-acoustic models from experimental modal analysis. The objective is, starting from experimental data associated to vibro-acoustic measurements (pressure in a cavity and accelerations on a structure), to identify a reduced model with a reduced number of degrees of freedom (typically, associated to measurement points) whose matrices topology is in accordance with fluid-structure interaction formulations. Several ways are available to attempt to identify this model, among which three are considered here for comparison. A first approach is related to the direct use of inverse technique, which often exhibits some conditioning troubles, a second one is related to the so-called properness of the identified complex vectors, a tool which is classically available for structural dynamics, and a third one which is associated to direct identification of matrices from experimental FRFs using a least square approach.