Strategies to Exploit Test Data in Subsystem Subtraction

In dynamic substructuring, the subtraction of subystems (decoupling) is a very critical problem even in apparently trivial applications. Using simulated FRF data, it has been highlighted that - as predicted by the theory - the solution of decoupling problems is affected by ill-conditioning around a discrete number of frequencies, and is dependent on the choice of the 'measured DoFs'. In experimental dynamic substructuring, additional problems can arise (systematic errors, inconsistencies, etc.) that are strictly connected with the use of measured FRFs, and different strategies to obtain reliable results can be necessary. In this paper, experimental data, acquired on a test bed made by a plate and a rigid mass, are used to check the decoupling procedure and to look for additional issues that can not be observed from simulated data.