Abstract: A flexible rotor system with squeeze film damper (SFD) was constructed and the static eccentricity of the SFD can be altered independently. Performance of the damper，resistance capability for the vibration and the character of the nonlinear vibration of the rotor are experimentally investigated under different static eccentricity level. The results reveal that the static eccentricity results in the increase of the critical speed. Critical amplitude decreases with the increase of the static eccentricity ratio [εs] when [εs]< 0.6，while the critical amplitude increases sharply with the increase of the static eccentricity ratio when 0.6 <[εs]< 1. When the static eccentricity rises，the unbalance of failure of attenuating vibration for the damper decreases significantly and the vibration resistance ability of the rotor is also influenced greatly. The static eccentricity ratio should be less than 0.2 to insure effective damping performances of SFD. The bistable jump phenomena are observed with a low level static eccentricity ([εs]<0.2)，while the non-linear soften-spring effect and the nonsynchronous vibration can be observed with a high level static eccentricity ([εs]>0.3)，when the failure of attenuating vibration happens. The vibration characteristics when damper fail to attenuate vibration can be used to identify the static eccentricity level of the damper.

Key words: Aero-engine；Squeeze film damper；Static eccentricity；Mechanical vibration；Non-linear vibration

摘要： 为研究静偏心对挤压油膜阻尼器减振特性的影响，设计了可单独改变油膜间隙的柔性转子系统，针对不同静偏心条件下，阻尼器减振性能，转子的抗振性能和非线性振动特征进行了实验研究。结果表明:静偏心会导致转子系统临界转速增大；静偏心比[εs]小于0.6，转子临界峰值随静偏心比增大而减小，[εs]在0.6 ~ 1.0范围内增大时临界峰值随静偏心比增大而大幅增大；[εs]增大时阻尼器失效不平衡量大幅减小，转子不平衡裕度和抗振性能大幅下降，将[εs]控制在0.2以内时，静偏心不会恶化阻尼器的阻尼效果；静偏心比([εs]<0.2)较小时，阻尼器失效表现为典型双稳态跳跃，静偏心比([εs]>0.3)较大条件下，阻尼器失效时可能表现出软弹簧非线性振动与非协调振动；根据阻尼器失效转子振动特征可判断阻尼器静偏心水平。

关键词: 航空发动机；挤压油膜阻尼器；静偏心；机械振动；非线性振动