Smorzatori sotto-pala per turbomacchine: un nuovo metodo basato sul calcolo simultaneo delle forze statiche e dinamiche di contatto.

Underplatform dampers are widely used to reduce vibration amplitude of turbine bladed disks by friction. They are metal devices placed under the blade platforms and held in contact with them by the centrifugal force acting during rotation. The common procedure used to calculate the static loads acting on underplatform dampers consists in decoupling the static and the dynamic balance of the damper. A preliminary static analysis of the contact is performed in order to compute the static pressure distribution over the damper/blade interfaces, assuming that it does not change when vibration occurs. In this paper a coupled approach is proposed to solve the static and the dynamic balance equations of the system. Numerical case studies are presented in order to show the capabilities of the method and the improvements with respect to the state of the art.