An eigen-analysis provides stability information for a rotor system, and it is also an important part of rotor aeroelastic analysis. The resonance phenomenon can be predicted by eigen-analysis as well. In this research, a new three-dimensional wake and nonlinear composite rotor blade flap-lag-torsion coupled model will be developed. The generalized dynamic wake model employed is based on an induced undetermined time dependent coefficients as aerodynamic states. The Galerkin's method and Duncan polynomials are used to expand this nonlinear coupled equation into equilibrium and disturbant parts. The nonlinear phenomenon will be investigated through eigen-analysis, especially for nonlinear resonance. Hopefully, some of the physical meanings behind the nonlinear resonance would be discovered through eigen-value point of view. 特徵值(eigen-value) 及特徵向量(eigen-vector) 的分析是一般分析旋翼系統之穩定性常用的方法。前者可提供各種飛行狀況或是各種材質的旋翼葉J:I~統的阻尼及振動頻率,後者則可提供各模式
(mode) 的振動模態(mode shape) ,更可幫助暸解旋翼葉片在各種飛行狀況的物理現象。本研究利用解析的方法將尾流運動方程、葉片空氣動力學及一個非線性複材葉片的結構運動方程整合成一搞合的系統,在某一選定的結構振動頻率範圍內,本研究將利用Galerkin 法及Duncan 多項式將其展開,並分成非線性平衡態及線性擾動態兩種方程式。而非線性部份將利用數值法求出與時間無關之靜、數,再與擾動項合併且線性化之後,利用Floquet 理論求解該系統之特徵值及特徵向量並尋求物理現象之解釋。