STABILITY AND DYNAMICS OF A ROTOR SYSTEM WITH A SLANT CRACK ON THE SHAFT

Stability and dynamics of a rotor system with a 45 slant crack on the shaft are analyzed in this paper. In the equations of transversal vibration, the stiffness of the shaft is expressed by a jump function since the torsional moment can make a slant crack totally open or close. Therefore, under the rotating coordinate system the transversal motion equation is a classic parametric excitation with the period identical to the torsional excitation. Analysis for the stability of the homogeneous equation shows the change of unstable areas with the stiffness. The steady-state response of the rotor system indicates that imbalance and gravity will produce different frequencies for the isotropic crack and anisotropic one. These results can be used for the slant crack detection.