9423774 Nayfeh An analytical and experimental investigation is conducted in to the transfer of energy from high-frequency to low- frequency modes in the responses of multi-degree of-freedom and distributed-parameter dynamic systems subjected to periodic excitations. Exchanges of energy between widely spaced modes are generic to certain classes of nonlinear systems and because of possible dire consequences, e.g., instability or chaotic motions, require a complete understanding. This research project demonstrates the energy- transfer phenomenon via relevant experiments; formulation of analytical models to explain the interactions between widely spaced modes of structures and using them to determine conditions under which energy can be transferred from high- frequency to low-frequency modes, as observed in the experiments; and the use of developed analytical models to identify possible control schemes to suppress these potentially dangerous transfers of energy.***
