Robust flutter analysis using interval modal analysis and continuation method

Abstract

For robust analysis of the flutter stability, it is necessary to consider the uncertainties of the structural dynamics model. These uncertainties can be clarified from estimates of uncertainties of the parameters in finite element models or from statistical evaluations of experiments. As a supplement to the reliable flutter algorithm for solution of the flutter equation, the continuation method is introduced, which allows the specific examination of individual solution branches of the flutter equations that risk being critical for stability. To compute the range of variations of eigenfrequencies and mode shapes caused by possible structural uncertainties, the interval modal analysis is introduced. The modal interval ranges are tracked through the flutter stability analysis. The deterministic computed intervals of critical flutter speeds are compared to the probabilistic results obtained by Monte-Carlosimulation.