Abstract
In this work, a new, flexible friction damper model is introduced, for application to turbomachinery bladed-disk assemblies. The damper is modeled as a massless structure characterized by a stiffness matrix. It is connected to two (possibly more) structural systems at an arbitrary number of friction points where slip can occur. A new procedure is presented to calculate the force transmitted by the damper at each frictional interface. The multi-harmonic, hybrid, frequency/time method introduced previously by the authors, along with the Broyden resolution algorithm, are modified to handle this advanced damper model and to predict the steady-state periodic response of the system. The method is successfully applied to a four-degree of freedom friction damper connecting two beams at four frictional points. Several interesting features of the non-linear response are revealed, such as: situations where the damper slips at some frictional points and sticks at the other points; and complexity of the frequency response of the system, due to the existence of several modes of vibration that correspond to combinations of stick/slip motions at the various frictional interfaces.
