Coupled Lateral and Torsional Vibration of Rub‐Impact Rotor during Hovering Flight
Nan Zheng, Moli Chen, Guihuo Luo, Zhifeng Ye
Abstract
When aircraft make a maneuvering during flight, additional loads acting on the engine rotor system are generated, which may induce rub‐impact faults between the rotor and stator. To study the rub‐impact response characteristics of the rotor system during hovering flight, the dynamic model of a rub‐impact rotor system is established with lateral‐torsional vibration coupling effect under arbitrary maneuvering flight conditions using the finite element method and Lagrange equation. An implicit numerical integral method combining the Newmark‐ β and Newton–Raphson methods is used to solve the vibration response. The results indicate that the dynamic characteristics of the rotor system will change during maneuvering flight, and the subharmonic vibrations are amplified in both lateral and torsional vibrations due to maneuvering overload. The form of the rub‐impact is different during level and hovering flight conditions: the rub‐impact may occur at an arbitrary phase of the whole cycle under the condition of level flight, while only local rub‐impact occurs during hovering flight. Under the both flight conditions, the rub‐impact has a large effect on the spectral characteristics, periodicity, and stability of the rotor system.