The rotor may operate at various working conditions in practice and the crack breathing behavior at different rotating speeds is essential for damage detection and health monitoring of rotor system. In this paper, the coupling of lateral and longitudinal vibration is investigated by building a Jeffcott rotor model with imbalance. By using D’Alambert Principle, four degree-of-freedom equation of motion is derived in fixed coordinate system and the crack model is built based on the fracture mechanics. Zero SIF method is used to determine the crack open area by computing the SIF of opening mode for every point in crack area. The stiffness matrix is updated every time step by integrating compliant coefficients over instantly calculated crack open area. In addition, the breathing behavior of the crack under axial excitation is studied in terms of several eccentricity phases and rotation speeds, which provide effective guidance for damage detection in such scenarios. The paper also explores the coupling effect of external axial loading on the vibration response and its effectiveness for damage detection.

This content is only available via PDF.
You do not currently have access to this content.