Sensitivity analysis of multiharmonic self-excited limit-cycle vibrations in gas-turbine engine structures with nonlinear contact interfaces

An efficient frequency-domain method is developed to calculate the sensitivity of multiharmonic amplitudes of the limit-cycle oscillations and their primary frequency to variation of the nonlinear contact interface parameters and aerodynamic characteristics. The method allows highly accurate and fast determination of the sensitivity coefficients together with the calculation of the limit-cycle amplitudes and frequencies using realistic large-scale finite element models of structures. The nonlinear contact interactions analysed include: friction contacts, unilateral interaction along normal direction at a contact interface, closing and opening clearances and interferences, cubic spring nonlinearity. The capabilities of the method are demonstrated on a set of test cases. Copyright 2014 by ASME.