Dynamic Response Analysis of Rotating Shaft-Bearing System with an Open Crack

Abstract

The best of effective design and practices of constructive methods in the analysis of rotor excessive vibration will yield the solutions for the dynamic problems. The extensive effusion of the finite element method (FEM) strongly induced in the area of rotordynamic studies and can give accurate results. Diagnosis of a rotor shaft with crack for its operating conditions is essential to the dynamic systems design. This paper carries the analysis of a finite element model of a flexible rotor-bearing system with a transverse open crack by accounting the various crack depths and internal damping of the shaft. The effect of transverse crack on the system instability regions was found out. It is noted that the natural whirl speeds reduce with increase in crack depths. The system unbalance response and damped natural whirl speeds are presented with undamped orthotropic bearings. The stability of the rotating shaft-bearing system with transverse open crack has also been studied for the various spin speeds and disk eccentricity with the time integration procedure. The phase-plane portraits and frequency-domain diagrams are drawn to study the dynamic behavior. Further, the study is yet to be extended to a fully levitated rotor model supported in active magnetic bearings (AMBs).