Modeling and analysis of coupling vibration of flexible disk-drum structure considering eccentricity effect

Eccentricity is a common failure of rotor systems in actual engineering such as disk-drum structures. This work aims to explore the coupling vibration of the disk-drum system considering the eccentricity effect. Firstly, the artificial spring method was utilized to express the bolted joint condition with an eccentricity. Then, considering the rotational effect, a new dynamic model of the flexible disk-drum with eccentricity was proposed. The correctness of the model was verified using the experiment. The frequency curves and mode shapes were used to discuss the coupling vibration behaviors of the eccentric disk-drum with or without rotation, specifically. The effect of eccentric magnitude on the coupling vibrations was investigated. The results show that eccentricity not only causes the frequency increase or decrease, frequency bifurcation, frequency veering, and vibration localization, but also the mode shape interaction and order exchange. As the eccentric magnitude increases, the frequency veering phenomena in the Campbell diagrams for the rotating disk-drum get more obvious and complex. The results will be helpful for the vibration prediction and dynamic design of the disk-drum in rotor systems.