A Novel Evaluation Method for Vibration Coupling of Complex Rotor–Stator Systems in Aeroengines

With the increase in thrust–weight ratio of advanced aeroengines, the rotor and stator often exhibit comparable stiffness characteristics, leading to significant vibration coupling which harms the safety and reliability of operations. However, an effective vibration coupling evaluation method for complex rotor–stator systems is still lacking. This paper proposes the Vibration Coupling Evaluation Factor (VCEF) to quantitatively evaluate the interaction between the rotor and stator within the framework of the linear system. Then a new evaluation procedure is established for the structural optimization during the early design phase and the fault source localization in troubleshooting scenarios in the high-speed rotating machinery. In this paper, two typical rotor–stator systems are studied with the VCEF method: a simplified rotor–stator system is studied numerically to reveal the influence pattern of different parameters, and a complex rotor–stator system is studied numerically and experimentally to examine the validity of the evaluation method. The results show that VCEF can effectively capture rotor–stator vibration coupling. The VCEF curve with rotational speed shows a significant stepped decrease, indicating a significant strengthening of the rotor–stator vibration coupling, which aligns closely with experimental data. This evaluation method quantitatively assesses the degree of rotor–stator vibration coupling by comparing the differences in modal characteristics between the rotor system and the rotor–stator system under the gyroscopic effect. Optimizing rotor–stator stiffness and mass distribution based on VCEF mitigates operational risks in high-speed regimes. This methodology provides engineers with a systematic, quantitative tool to determine when integrated rotor–stator analysis is essential for accurate dynamic prediction and offers broad applicability to aeroengine design and other high-speed rotating machinery.