Internal Resonance Phenomena of an Asymmetrical Shaft. In the Vicinities of the Major Critical Speed and Critical Speed of Three Times the Major Critical Speed.

An asymmetrical shaft has been investigated for many years because unstable vibrations appear in this rotor system. However, when the natural frequencies hold simple integral relation exactly or approximately, an internal resonance may occur and the nonlinear phenomena change remarkably. In this study, the nonlinear oscillations and internal resonance phenomena of an asymmetrical shaft are investigated theoretically and experimentally in the vicinities of the major critical speed and critical speed of three times the major critical speed. Further, we clarified characteristics of nonlinear phenomena in the transition from the system with internal resonance to the system with no internal resonance.