Explicit Finite Element Models of Friction Dampers in Forced Response Analysis of Bladed Discs

Abstract

A generic method for analysis of nonlinear forced response for bladed discs with friction dampers of different design has been developed. The method uses explicit finite element modelling of dampers, which allows accurate description of flexibility and, for the first time, dynamic properties of dampers of different design in multiharmonic analysis of bladed discs. Large-scale finite element damper and bladed disc models containing 104–106 DOFs can be used. These models, together with detailed description of contact interactions over contact interface areas, allow for any level of refinement required for modelling of elastic damper bodies and for modelling of friction contact interactions. Numerical studies of realistic bladed discs have been performed with three different types of underplatform dampers: (i) a ‘cottage-roof’ (called also ‘wedge’) damper; (ii) seal wire damper; and (iii) a strip damper. Effects of contact interface parameters and excitation levels on damping properties of the dampers and forced response are extensively explored.