A comparative study on time–frequency feature of cracked rotor by Wigner–Ville distribution and wavelet transform

Based on the simple hinge crack model, the dynamic equation of transient response in a cracked rotor system is modelled; the numerical simulation solutions of the cracked rotor and the uncracked rotor are obtained from the model. The time–frequency features of the cracked and the uncracked rotors obtained by using the Wigner–Ville distribution are compared with those obtained by using the wavelet transform, the difference is presented. By simulation research, the sensitivity of the Wigner–Ville distribution and the wavelet transform to the stiffness variation is investigated; and the influence of the unbalance and the unbalance angle on the Wigner–Ville distribution and the wavelet transform is discussed. The time–frequency features are unique, which can be used as the criteria for identification of cracked rotor.