An analysis method to determine how changes in dynamic complexity impact on rotor-bearing systems

• Published in: Proceedings of the Institution of Mechanical Engineers. Part C, Journal of mechanical engineering science Journal of mechanical engineering science, 2021-10, Vol.235 (20), p.4569-4581
• Main Authors: Jiang, Mian, Liu, Shuangqi, Wang, Yuhua
• Format: Article
• Language: English
• Subjects: Complexity; Condition monitoring; Diagnosis; Dynamical systems; Lubricating oils; Nonlinear dynamics; Nonlinearity; Parameters; Rotor-bearing systems
• ISSN: 0954-4062; 2041-2983
• DOI: 10.1177/0954406220954887

Condition monitoring performance and diagnosis of rotor-bearing systems depend not only on the methods used, but also on the dynamic complexity of the system itself. Thus, it is important to analyze how changes in parameters under various working conditions impact on dynamic complexity. Most of previous research efforts on this topic have been focused on the analysis of nonlinear dynamics of rotor-bearing systems with different parameters. In this paper, a nonlinearity quantification based analysis method is presented to determine how parameter dynamics impact the complexity of rotor-bearing systems. The dynamic complexity of rotor system is estimated using defined nonlinearity measures. To validate this method, a sliding rotor-bearing system with a loose pedestal is used. The estimates (nonlinearity degrees) and the states of motion are matched with increasing rotational speeds. It is then investigated, how the eccentricities, lubricating oil viscosities, and bearing clearances impacted the dynamic complexity at several critical rotational speeds. These results can guide methodological choices for condition monitoring and diagnosis of rotor systems.