Time simulation of flutter with large stiffness changes

Abstract

Time simulation of flutter, involving large structural changes, is formulated with a state space model that is based on a relatively small number of constant generalized coordinates. Vibration modes are first calculated for a nominal finite element model with relatively large fictitious masses located at the area of structural changes. A low frequency subset of these modes is then transformed into a set of structural modal coordinates with which the entire simulation is performed. These generalized coordinates and the associated oscillatory aerodynmaic force coefficient matrices are used to construct an efficent time domain , state space model for a basic aeroelastic case