MATHEMATICAL MODELLING AND STABILITY ANALYSIS OF AN AEROELASTIC 3 DEGREE OF FREEDOM WING SECTION MODEL

Abstract This paper discusses the modeling and stability analysis of aero elastic system. Aero elastic system represents interaction between structural/mechanical forces and aerodynamic forces, which may occur in some engineering applications, such as in flying vehicle structures, flexible structures, wind-turbine blades, etc. The Aero elastic phenomena are one of significant factors which must be considered in the design of structural-fluid interaction system due to its relation to the stability of the system. Flutter is one of the aero elastic phenomena which correspond to the dynamic stability of a structure-fluid system. Flutter is usually indicated by the occurrence of excessive structural vibration which may lead to structural failure. In aeronautical engineering field, flutter becomes factor that can limit the performance and operation regime of flying vehicles. In this paper a 3 Degree of Problem aero elastic system, involving elastic and rigid body modes is mathematically modeled and analyzed. Analysis is focused on the dynamic stability characteristics of the system, including the effect of rigid body mass has on the stability characteristic of the system. The mathematical model is developed based on the equation of motion of the system involving the unsteady aerodynamic loads which are computed using Doublet Point Method (DPM). The stability analysis is conducted via Eigen value evaluation on augmented state space model transformed from the equation of motion of the system. The numerical analysis shows that the two elastic modes of the system could interaction each other and causing flutter instability to occur at particular airspeed, called the flutter speed. It is also observed that the inclusion of rigid body mass on the system affects the stability of the system, indicated by a shift on the system flutter speed.Hlm. 110-12