A real-time coupling model and kinetic behavior of flexible dual-rotor-bearing systems with blade-casing rubbing-impact

Abstract

Blade-casing rubbing impact is a prevalent failure mode in aeroengine rotor systems. This study presents a real-time coupled model for the dual-rotor-bearing system, aimed at investigating the vibration transmission and behavior interference between system components. In this model, dedicated methods are developed to characterize the flexible components and the rubbing-impact phenomena, while the real-time coupling relationship is formulated. By integrating experimental testing with software analysis techniques, the influence mechanisms of rubbing-impact failure on system behavior response and bearing contact process are comprehensively revealed. Rotor deformation compels the bearings to operate persistently under misaligned conditions, resulting in the introduction of contact angles and reversal zones in the ball-race contact direction. The effects of the bearing system on rotor dynamics are categorized into three aspects: low-speed instability, contact reversal zone and non-periodic behavior, all of which contribute to the generation of harmonic responses. Moreover, periodic malicious rubbing-impact forces are induced by modal vibrations, which reduce system vibration intensity and bearing contact angles. However, the stable operation is disrupted and the critical speed is delayed, while a reduction in blade-casing clearance contributes to the expansion of rubbing-impact zone and the chaotic system behavior.