Fault Diagnosis of Mistuned Preload in Rod Fastened Rotor in Gas Turbine Based on CWT

Rod fastened rotor is widely used in heavy duty gas turbine, its dynamic behavior directly effects the security and efficiency of the gas turbine set. The preload detuning is one of the common faults of the rod fastened rotor, it will increase the vibration and threaten the stable operation of the system. In this paper, the effect of preload force on interface between disks is simplified to the bending stiffness of interface by sub-model stiffness method, which is verified by modal test. Secondly, the finite element model of rod fastened rotor is established, the correctness of this model is proved by comparing the calculated and experimental orbits results. Finally, the transient response during the relaxation is simulated by finite element model, and the common time-frequency domain signals are obtained by continuous wavelet transform (CWT). This research contents and methods can provide ideas and references for rod fastened rotor preload mistuned fault analysis.