An Evaluation Method for Dry Friction Damping of Ring Damper in Gas Turbine Engines under Axial Vibration

Abstract

The blisks and labyrinth seals in gas turbine engines are typical rotating periodic structures. Vibration problems will inevitably occur during the operation, which can easily lead to High Cycle Fatigue failure of the structure. Adding ring damper is an effective means of structural vibration reduction. The damper uses the dry friction of the contact surface to dissipate the vibration energy, improve the damping of the system, and then reduce the vibration response of the structure. The structures have a nodal diameter and modal shape, and the forced vibration often presents the characteristics of traveling wave. In this paper, an evaluation method for dry friction damping of ring damper under the axial component of traveling wave vibration is established. For the given vibration stress at the critical location, the equivalent damping ratio provided by the ring damper is calculated based on the friction energy dissipation and the damping characteristic curve that is the equivalent damping ratio varying with the vibration stress is obtained. This method can avoid calculating the nonlinear dry friction forced response and is suitable for the design stage. The damping of split ring dampers with rectangular section for one blisk and labyrinth seal is analyzed in this paper. It is shown that rotating speed, friction coefficient, section area and material density significantly influence the damping characteristics. There are many factors affecting the damping characteristics of the damping, so it is necessary to comprehensively consider various factors and multiple modes for vibration reduction design.

Keywords

• dry friction damping
• energy dissipation
• ring damper
• blisk
• labyrinth seal