Dynamic Characteristics and Experimental Research of a Two‐Span Rotor‐Bearing System with Rub‐Impact Fault

Rotor rub‐impact has a great influence on the stability and safety of a rotating machine. This study develops a dynamic model of a two‐span rotor‐bearing system with rubbing faults, and numerical simulation is carried out. Moreover, frictional screws are used to simulate a rubbing state by establishing a set of experimental devices that can simulate rotor‐stator friction in the rotor system. Through the experimental platform and its analysis system, the rubbing experiment was conducted, and the vibration of the rotor‐bearing system before and after the critical speed is observed. Rotors running under normal condition, local slight rubbing, and severe rubbing throughout the entire cycle are simulated. Dynamic trajectories, frequency spectrum diagrams, chart of axis track, and Poincare maps are used to analyze the features of the rotor‐bearing system with rub‐impact faults under various parameters. The vibration characteristics of rub impact are obtained. Results show that the dynamic characteristics of the rotor‐bearing system are affected by the change in velocity and degree of impact friction. The findings are helpful in further understanding the dynamic characteristics of the rub‐impact fault of the two‐span rotor‐bearing system and provide reference for fault diagnosis.