Study on the friction damping characteristics of bladed disk (Comparison of microslip model and macroslip model)

The vibration characteristics of a bladed disk with the continuous ring type structure have been studied extensively, and the vibration response analyses considering the friction damping between adjacent shrouds have been performed in the recent blade design. The effect of the friction damping on the self-excited vibration also has been studied by several researchers. However, because the most of these studies have been performed using the simple macroslip model, the damping characteristics of bladed disks with the friction damping are not yet clarified sufficiently. In this paper, the damping characteristics of the bladed disks with the continuous ring type structure is studied using the conventional macroslip model and the sophisticated microslip model for the forced and self-excited vibration and the results calculated by both models are compared. From the analysis results, it is concluded that, in the forced vibration, the damping characteristics predicted by both models are almost the same if the excitation force is extremely large or small. However, when the excitation force is medium, the damping characteristics predicted by both models are different. In the self-excited vibration, the stability predicted by both models are qualitatively the same. However, the amplitude of the limit cycle oscillation and the critical aerodynamic damping predicted by both models are quantitatively different.