Modeling of misaligned bearing induced by coupling misalignment and assembly errors and vibration analysis in dual-rotor system

• Published in: Mechanical systems and signal processing Vol. 230; p. 112656
• Main Authors: Guan, Hong, Wang, Pengfei, Xiong, Qian, Ma, Hui, Zhou, Sainan, Mu, Qinqin, Zeng, Yao, Chen, Yanyan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2025
• Subjects: Bearing assembly errors; Coupling misalignment; Dual-rotor system; Nonlinear vibration; Coupling misalignment; Bearing assembly errors; Nonlinear vibration; Dual-rotor system
• ISSN: 0888-3270
• DOI: 10.1016/j.ymssp.2025.112656

In rotating machinery, coupling misalignment is one of the most common faults, second only to rotor imbalance. Previous studies on coupling misalignment have often overlooked its effects on bearing contact characteristics and the resulting multi-directional displacement (misalignment) of the bearings. Therefore, this paper focuses on investigating the effects of coupling misalignment on bearing contact characteristics and the vibration response of the rotor, explicitly considering bearing misalignment. However, existing bearing misalignment models are limited to capturing misalignment in only a single direction. To bridge the gap, a new five-degree-of-freedom bearing model is proposed, which considers multi-directional misalignment. The proposed model is then validated through both the experimental testing and simulation using ROMAX software. Based on this validated model, a dynamic model of the coupling-dual rotor-bearing system is developed, and the vibration responses are analyzed, considering bearing misalignment induced by both coupling misalignment and bearing assembly errors. The results indicate that: (1) the proposed model reveals new frequency components, providing novel insights for fault detection and predictive maintenance in mechanical systems; (2) the ball contact load increases by approximately six times when bearing misalignment induced by coupling misalignment is considered; (3) the combined frequency associated with the varying compliance (VC) frequency can be used to distinguish whether the bearing misalignment is caused indirectly by the coupling misalignment or directly by the bearing assembly errors; (4) under combined misalignments, the constraining effect of bearings can either counteract or amplify, with the overall effect reaching up to 31.25% compared to cases with single-directional misalignment. The precision of simulation signals is improved by the proposed model, especially the combination frequency and VC frequencies of bearings, enhancing diagnostic capabilities for fault detection in mechanical systems.