带气膜阻尼悬臂平板的振动特性研究

针对航空发动机叶片振动疲劳损伤问题,建立了带振动能量耗散机制的气膜阻尼理论模型.将气膜内气体的流动分别等效为牛顿流体的流动和泊肃叶流体的流动,推导出气膜阻尼结构的阻尼比方程,研究了带气膜阻尼悬臂平板的振动特性.目的是为航空发动机风扇叶片气膜阻尼的结构设计提供理论依据和技术支撑.结果表明:泊肃叶流体能够考虑更多的振动能量...

Research on Vibration Characteristics of Cantilever Plate with Air Film Damper

In view of the fatigue damage suppression problem of aeroengine blade,a theoretical model of vibration energy dissipation mechanism in the air film damper(AFD)is established.The air flow within the air film is considered as Newtonian fluid and Poiseuille fluid respectively,the damping ratio of the AFD structure is thus deduced and the vibration characteristics of the cantilever plate with AFD are studied.The purpose is to provide theoretical basis and technical support for the structural design of AFD in the aeroengine fan blade.Results show that the damping ratio calculated by Poiseuille fluid is larger than that of Newtonian fluid due to a more refined energy dissipation mechanism;the optimal thickness of air film exists when the plate vibrates at low frequencies and the influence of boundary layer cannot be ignored;the geometric dimensions of AFD such as film thickness and length have great influence on the vibration suppression effect which should be considered in its design.The installation position of the AFD not only affects its vibration suppression effect,but also changes the resonance frequency of the plate.