Experiments in energy pumping in vibrating mechanical systems

Nonlinear energy pumping is the rapid, irreversible transfer of energy during transient resonant captures between vibrating subsystems. The last few years have seen many significant developments in the theory of this phenomenon, and excellent agreement has generally been observed between various analytical results and numerical simulations. In a series of recent experiments, we have attempted to demonstrate in the laboratory some of the features of energy pumping predicted by analysis, such as resonance capture cascades in which a single-degree-of-freedom substructure interacts with a sequence of natural modes of the main structure to which it is attached. This talk will briefly review the theory of energy pumping from one- and two-DOF primary systems into a SDOF nonlinear energy sink (NES), then focus on the apparatus used and the results of recent experiments.