非线性油膜力作用下叶片-转子-轴承系统弯扭耦合振动特性研究

建立了叶片-转子-轴承系统模型,并分析了考虑非线性油膜力作用下系统的弯扭耦合运动。为了考虑叶片弯曲变形的影响,将叶片模化为悬臂梁结构,利用假设模态法进行离散求解,通过Lagrange方法建立系统的运动方程,运用Runge-Kutta法对所得动力学方程进行数值求解,最终通过对分岔图、三维谱图、相图和Poincaré映射的分析,得到了叶片-转子-轴承系统中蕴含的各种复杂非线性动力学行为。通过与不考虑叶片的转子-轴承系统进行比较,指出叶片的弯曲振动使系统的不稳定区域提前,并在某些转速下激起系统的混沌运动。

RESEARCH ON COUPLED BENDING AND TORSION VIBRATION OF BLADE-ROTOR-BEARING SYSTEM WITH NONLINEAR OIL-FILM FORCE

A coupled bending and torsion model of blade-rotor-bearing with nonlinear oil-film force was presented. To analyze the impact of blade-bending, the blade was assumed to be a cantilever beam and then discretized using the assumed modes method. The motion equation was established by the Lagrange approach and numerically calculated by Runge-Kutta method. The bifurcation diagrams, waterfall plot, phase spectrum map and poincarésection were obtained to analyze dynamic characteristics of the system. The results reveal multiform complex nonlinear dynamic behavior of the blade-rotor-bearing system. Thorough a comparison with the system whose blades were not considered, it is shown that the blade-bending vibration advances the unstable region of the system and arises the chaotic motion of the system in some rotational speeds.