State-space domain virtual point transformation for state-space identification in dynamic substructuring

In this article, the construction of state-space models suitable for dynamic substructuring (DS) applications is analysed in detail. The procedure derives the state-space model from the Frequency Response Functions (FRFs) measured on the components involved in the DS application. Moreover, a system identification algo rithm is used to estimate the modal parameters from these FRFs. All the steps to properly construct a reliable state-space model by using the estimated modal parameters are presented and deeply analysed. Furthermore, the well-known Virtual Point Transformation (VPT) method is extended to the state-space domain. The ap proaches here discussed are validated by exploiting a set of FRFs collected from an experimental dynamic characterization of a mechanical system composed of two cross-shaped structures connected by a rubber mount. The paper demonstrates that the FRFs of the estimated state-space models very well-match the FRFs obtained by applying the VPT approach on the measured FRFs.