Complex Harmonic Wavelet Analysis of a General Rotor System with a Breathing Crack

This study investigated complex harmonic wavelet analysis, using a complex coordinate system, for a general rotor system with a breathing crack. For this purpose the equation of motion was derived for a general rotor system with a breathing crack modeled by switching stiffness action, for which the transient response was analyzed by the complex harmonic wavelet method. Thereby, the modal characteristics according to the crack presence can be investigated on a response generally including steady and transient states. From this result, the technique to detect the presence of a breathing crack in the shaft, formerly limited to the steady state, can be expanded to the case of a transient state.