Nonlinear vibration and stability analysis of an aero-engine dual-rotor system subjected to high-frequency excitation
Rongzhou Lin, Shuangxing Ren, Lei Hou, Zeyuan Chang, Zhihong Li, Yushu Chen, Nasser A. Saeed, Mohamed S. Mohamed
Abstract
This paper analyzes the nonlinear dynamic characteristics and stability of Aero-Engine Dual-Rotor (AEDR) systems under high-frequency excitation, based on the Adaptive Harmonic Balance with the Asymptotic Harmonic Selection (AHB-AHS) method. A finite element dynamic equation for the AEDR system is introduced, considering complex nonlinearities of the intershaft bearing, unbalanced excitations, and high-frequency excitation. A solving strategy combining the AHB-AHS method and improved arclength continuation method is proposed to solve high-dimensional dynamic equations containing complex nonlinearities and to track periodic solutions with parameter variations. The Floquet theory is used to analyze the types of bifurcation points in the system and the stability of periodic motions. The results indicate that high-frequency excitation can couple high-order and low-order modes, especially when the system undergoes superharmonic resonance. High-frequency excitation leads to more combination frequency harmonics, among which N f ω 1 -2 ω 2 dominates. Furthermore, changing the parameters (amplitude and frequency) of high-frequency excitation widens or shifts the unstable regions of the system. These findings contribute to understanding the mechanism of high-frequency excitation on aero-engines and demonstrate that the proposed AHB-AHS method is a powerful tool for analyzing high-dimensional complex nonlinear dynamic systems under multi-frequency excitation.