Effect of Stiffness Uncertainties on the Flutter of a Cantilever Wing

Abstract

This paper deals with the investigation of the influence of spanwise distribution of bending and torsion stiffness uncertainties on the flutter behavior of an aeroelastic wing using a stochastic finite element approach. The analysis adopted a numerical algorithm to simulate unsteady, nonlinear, incompressible flow (based on the unsteady vortex lattice method) interacting with linear aeroelastic structure in the absence of uncertainties. The airflow and wing structure are treated as elements of a single dynamic system. Parameter uncertainties are represented by a truncated Karhunen-Love expansion. Both perturbation technique and Monte Carlo simulation are used to establish the boundary of stiffness uncertainty level, at which the wing exhibits flutter in the form of limit-cycle oscillations and above which the wing experiences dynamic instability. The analysis also includes the limitation of perturbation solution for a relatively large level of stiffness uncertainty.