This focuses on the development of procedures which integrate modern dynamical systems theory and analytical/numerical techniques to characterize the dynamical behavior of systems with strong local nonlinearities. The emphasis will be placed on nonlinearly coupled rotor/structural systems such as high speed aircraft engines. Strong local nonlinearities in rotor systems are manifested in dampers, clearances, fluid interactions, rubs, and others. The systems may be subjected to single or multi frequency excitation due to rotating imbalance in single, or multiple shaft and/or geared systems, respectively. General procedures will be developed for determining the system's multiple, periodic and quasi-periodic responses, their detailed bifurcations and routes to chaos. Low order rotor models will be constructed to study the nonlinear mechanisms by which the regular and chaotic behavior of the systems influence their performance. Of particular interest is the effect of internal resonances on that behavior. The research will yield reliable methods and procedures which will contribute to the fundamental understanding of nonlinear phenomena in systems with strong nonlinearities. The methods will be generalized to efficiently treat large order rotor systems to aid in their simulation, design, testing and monitoring; and for future developments in experimental and analytical studies.*** //
