Optimisation of dynamic vibration absorbers over a frequency band

This paper is focused on the reduction of vibration levels of mechanical sy stems using dynamic vibration absorbers (DVAs). A general methodology is pr oposed for the optimum selection of DVA parameters so as to guarantee the e fficiency of those devices over a previously selected frequency band. The p resented methodology utilises a substructure coupling technique exploring f requency response functions (FRFs), which enables one to calculate the FRFs of the composite structure (primary system + DVAs), from the FRFs of the p rimary structure and the theoretical expressions of the FRFs of the DVAs. T he FRFs of the composite structure, which are expressed as functions of the DVA parameters, are then used to define scalar performance indexes related to the vibration levels of the composite structure over the selected frequ ency band. These performance indexes are optimised with respect to the DVA parameters by solving a general non-linear constrained optimisation problem . The first part of the paper is devoted to the formulation of the substruc ture coupling method and the optimisation procedures. Numerical application s using experimentally acquired FRFs are then presented to illustrate the m ain features of the proposed methodology. (C) 2000 Academic Press.