NONLINEAR AEROELASTICITY IN ROTORCRAFT

This paper is an overview of a research program for nonlinear aeroelas ticity of rotorcraft in forward flight conducted at Duke University an d supported by the Army Research Office. Theoretical and experimental investigations of rotor aeroelastic stability and nonlinear response a re described. A flexible rotor blade model with geometrical and freepl ay structural nonlinearities and the ONERA stall aerodynamic model are considered. Analytical and numerical solutions of nonlinear mathemati cal models and experimental methods for flutter and forced response in a wind tunnel environment are discussed. Correlations between theoret ical and experimental results are presented and some significant concl usions are drawn. It is hoped that this paper will help provide improv ed fundamental understanding of the nonlinear aeroelastic behavior of rotorcraft.