Effectiveness of Impact-Synchronous Time Averaging in determination of dynamic characteristics of a rotor dynamic system

Dynamic characteristics of rotor dynamic systems, namely natural frequencies, damping and mode shape, vary with rotation speed due to gyroscopic effect. To consider such effect, modal analysis is required to be performed while in operation. However, to generate the frequency response functions, it is not viable to perform data reduction in frequency domain as noise and harmonics excited by rotating forces dominate the spectrum and hide the natural frequencies. The full set of dynamic characteristics is difficult to obtain. A novel technique, referred to as Impact-Synchronous Time Averaging (ISTA), is developed in this study to screen out the noise and harmonics.