Study on the transient response and wavelet time—frequency feature of a cracked rotor passage through a subcritical speed

The dynamic model in dimensionless form of the transient response of a cracked rotor system is derived, which is based on the simple hinge crack model. By numerical simulation, the transient responses of the uncracked rotor and the cracked rotor are obtained and the subharmonic resonance of the cracked rotor is analysed. The influence of the unbalance, the inhabiting angle and the stiffness variation on the transient response is investigated. The wavelet time-frequency features of the cracked rotor and the uncracked rotor are studied, and the difference between them is discussed. The numerical simulation demonstrates that the wavelet analysis algorithm is valid for the identification of cracked rotor.