Flutter Boundary Prediction of a Digitized Aeroelastic Multi-Mode System

Abstract

This paper presents a preliminary study for a simulation analysis on flutter boundary prediction of a digitized aeroelastic system with multi-degrees of freedom in which a higher aeroelastic mode is involved in the occurrence of flutter. During flutter tests the conventional flutter boundary prediction is mostly performed through measurement of dampings of the aeroelastic modes. However, as the dampings often do not show any major change or sign for approaching the flutter boundary until the speed is closed to it. In this paper our previous discrete-time approach based on the flutter margin for discrete-time systems (FMDS) applicable only to a binary-mode system is extended to a multi-mode system, by using the basic principle, that is, Jury’s stability criterion instead of FMDS. Numerical results show that Jury’s criterion is much more useful in predicting the critical boundary of the multi-mode aeroelastic system than the conventional damping approach.