Dynamic modeling and response analysis of misaligned rotor system with squeeze film dampers under maneuver loads.

The low-pressure rotor system of an aircraft engine includes a fan rotor and a low-pressure turbine rotor, which are connected and fixed by a gear coupling. The existence of machining errors and assembly errors can cause rotor assembly misalignment, which is one of the important factors causing aircraft engine failures. Based on the finite element matrix set theory, this paper establishes a dynamic model of the aircraft engine rotor system, including the climbing maneuver load, nonlinear contact force of bearings, oil film force of SFDs, gravity field, additional force caused by coupling misalignment, and rotor misalignment imbalance force, considering the climbing maneuver load. Using Newmark-β algorithm to solve the misaligned rotor system model with SFDs. The influence of misalignment stiffness, clearance of the oil film, and bearing clearance on the motion state of the rotor system were analyzed in detail through bifurcation diagrams, axis trajectory diagrams, and frequency spectra. And analyze and cross compare the effects of three influencing factors on the system motion state under different maneuvering load environments. Through comparative analysis, it was found that among these three influencing factors, the misalignment stiffness of the sleeve coupling has the smallest effect on the system's motion state, but an appropriate intermediate value needs to be selected. The effect of rolling bearing clearance on the system's motion state is small and regular, while the impact of oil film clearance on the system's motion state is large and complex. The research results of this paper can provide theoretical support for parameter selection in the simulation and design of dynamic phenomena with misalignment faults in aircraft engines during maneuvering flight. [ABSTRACT FROM AUTHOR]