Experimental dynamic substructuring: significance and perspectives

Dynamic substructuring allows to describe an assembled structural system in terms of component subsystems. In experimental dynamic substructuring, the model of at least one (sub)system derives from experimental tests: this allows to consider systems that may be too difficult to model. The degrees of freedom (DoFs) of the assembled system can be partitioned into internal DoFs (not belonging to the couplings) and coupling DoFs. A possible application of experimental dynamic substructuring is substructure decoupling, i.e. the identification of the dynamic model of a structural subsystem embedded in a structural system known from experiments (assembled system) and connected to the rest of the system (residual subsystem) through a set of coupling DoFs. Coupling DoFs are often difficult to observe, either because they cannot be easily accessed or because they include rotational DoFs. However, whilst coupling DoFs and in particular rotational DoFs are needed when coupling together different subsystems, they are not essential in substructure decoupling, because the actions exchanged through the coupling DoFs are already included in the dynamic response of the assembled system. The most promising fields in substructure coupling are: coupling with configuration dependent interface and nonlinear coupling with localized nonlinearities. With reference to substructure decoupling, the most remarkable topics are: interface optimization, configuration dependent coupling conditions, and joint identification.