9402278 Bajaj In this research project the response of nonlinear systems to nonstationary excitations is investigated leading to analytic relationships between nonlinear system parameters and nonstationary response characteristics, such as maximum response amplitude and timing of sudden jumps in amplitude. These relationships are helpful in the design of vibration isolation strategies for the dynamic characteristics of highly nonlinear systems, for example, response of rotating machinery during startup and acceleration through critical speeds. The research methodology uses a combination of the traditional asymptotic nonlinear vibration theory and the recently developed dynamic bifurcation theory. Amplitude characteristics of the nonlinear response of single and multi-degree-of-freedom systems are investigated analytically, and the results are validated experimentally using lightly damped beams subjected to harmonic excitations. ***
