Experimental Evaluation of Dynamic Characteristics of Circular Arc Spring Dampers for Rotating Machinery

Abstract

This study presents an experimental evaluation of the dynamic characteristics of the circular arc spring damper (CASD), which attenuates the vibration of rotating machinery. A major advantage of CASDs over conventional Squeeze Film Dampers (SFDs) with squirrel-cage springs is their compactness and low weight. However, the basic characteristics of this type of damper, including the influence of the geometries, added mass coefficients, and cross-coupled terms of dynamic coefficients have not been investigated. To clarify these characteristics, a series of excitation tests was conducted on three types of CASDs to identify their dynamic coefficients. Tested dampers have the same outer diameter and damper width but different arc patterns and radial clearances. All dampers were tested in both open-end and end-sealed configuration. The influence of the end-seal clearances was also examined. The following results were obtained: (1) 4-arc type CASDs have greater damping than that of 2-arc types; (2) CASDs have a considerable amount of added mass coefficients, especially in the end-sealed condition; (3) Smaller end-seal clearances make the damping and added-mass coefficients significantly larger; (4) A large level of damping can be produced with dashpot configuration (large radial clearances and small end-seal clearances), though the added-mass effect becomes more prominent; (5) Cross-coupled terms are very small in centered / small amplitude motion. These new findings can be utilized for the design and application of CASDs to real rotating machineries.

Analysis of Dynamic Characteristics of Small-Scale and Low-Stiffness Ring Squeeze Film Damper-Rotor System

“…Their simplicity of construction and consequent robustness means that they are commonplace in modern aircraft gas turbine engines [4,5]. Although SFDs have been frequently used in the turbo-machinery industry, the non-synchronous vibrations can result in some problems of fatigue [6,7]. Thus, it is a tremendous requirement to investigate and improve the ring SFD-rotor system dynamics for vibration attenuation of high-speed small rotating machinery.…”