Dynamic Behavior of Twin-Spool Rotor-Bearing System with Pedestal Looseness and Rub Impact

The twin-spool rotor-bearing system plays a crucial role in the aero-engine. The potential manufacturing defect, assembly error, and abnormal working loads in the rotor-bearing system can induce multiple rotor failures, such as bolt looseness and rub impact. However, the prediction of the fault rotor dynamic behavior for the aero-engine remains a difficult frontier in numerical modeling. We present a dynamic model of the twin-spool rotor-bearing system, the failure model of bearing seat loosening, and the failure model of rub impact by using second-type Lagrangian equations, finite element theory, and the Timoshenko beam theory. In particular, to improve the accuracy of the numerical model, the rotating speed control equation and the actual aero-engine parameter are taken into account. An analysis is conducted on the impact of critical failure parameters, such as looseness stiffness and rub impact initial gap, on the vibration behaviors of the essential components of the twin-spool rotor system and on the entire engine. Additionally, this paper examines the twin-spool rotor-bearing system affected by looseness-rub coupled failures. The obtained conclusions can serve as a theoretical foundation for optimizing the structure and diagnosing faults in the aero-engine rotor system.