Analysis of flutter-induced limit cycle oscillations in gas-turbine structures with friction, gap and other nonlinear contact interfaces

A frequency-domain method has been developed to predict and comprehensively analyse the limit-cycle flutter-induced vibrations in bladed discs and other structures with nonlinear contact interfaces. The method allows, for the first time, direct calculation of the limit-cycle amplitudes and frequencies as functions of contact interface parameters and aerodynamic characteristics using realistic large-scale finite element models of structures. The effects of the parameters of nonlinear contact interfaces on limit-cycle amplitudes and frequencies have been explored for major types of nonlinearities occurring in gasturbine structures. New mechanisms of limiting the flutter-induced vibrations have been revealed and explained.