On the Implementation of Metastructures in Rotordynamics

Abstract

This paper presents the possibility to apply distributed vibration absorbers to reduce the vibration amplitude in axially symmetric components. The kind of metastructures here presented does not require complicated and expensive production processes such as additive manufacturing, but can be manufactured with more conventional means, for example with wire electrical discharge machining (EDM). Flexible rotating structures have a lot of natural frequencies in the operative range and the geometry changing approach is often not sufficient to improve the dynamic behavior. Using structural damping becomes fundamental to increase the transmitted power and the system life. In the present paper, the authors investigate the possibility to apply different geometrical configurations, each designed and tuned to suppress a particular mode shape, by means of the metastructure concept applied to flexible rotating devices. Their performances are analyzed with and without a balanced mistuning added to the metastructure. A number of distributed absorbers is set in order to act on each mode to be damped. Their vibration amplitude is firstly compared by keeping the total mass constant with respect to the original component, but also cases with higher and lower mass are analyzed. The frequency response of the proposed configurations is obtained from three-dimensional (3D) finite element models and some interesting results are evinced.