Compression Mechanics of the SC-MR Support for Rotor System

Abstract

The elastic damping support for rotor system which is combined of squirrel cage and metal rubber (also called metal mesh) and named SC-MR support for short is presented here. The SC-MR support is designed for flexible rotor system in turbo machineries, such as turbo-pumps and aeroengines. The SC-MR support realizes the function of both the elastic support and damping, which can provide a wonderful solution to the vibration problems. The squirrel cage supplies the main support stiffness and the Metal Rubber supplies the main damping and parallel stiffness. By controlling the parameters of the squirrel cage and the Metal Rubber, the stiffness and damping of the support could be designed to certain ranges. The stiffness of the squirrel cage and the SC-MR support was simulated by FEM models and the values are 2.13e7 N/m and 2.51e7 N/m respectively. The squirrel cage supplies more than 80% of the stiffness and the MR supplies minor parallel stiffness, which perfectly meets the design purpose. The effects of the installation state on the mechanical characteristics of the support were researched by compression tests. The Quasi-static tests on the squirrel cage show that its stiffness is 2.19e7 N/m, almost the same as simulated result. The compression tests on the SC-MR support were conducted while the Metal rubber was assembled with several prescribed prestrains. The results show that the support stiffness exhibits an increasing trend with either the radial prestrain or the axial prestrain, and it is more sensitive to the former one. The damping also appears to show an increasing trend with the prestrains and the loss factor is always larger than 0.02, distributing in range 0.02–0.08. The parallel stiffness of the MR increases severely with the prestrain. Therefore, the effect of the installation should be taken into account during the structure design process.