Structural Health Monitoring of a Nonlinear Aeroelastic System Based on Attractor Analysis

Abstract

The dynamic response of a thermo-shielding panel forced by unsteady aerodynamic loads and a archetypal Duffing oscillator are investigated to detect structural damage. A nonlinear aeroelastic model is obtained for the panel by using third order piston theory to model the unsteady supersonic flow which interacts with the panel. To identify damage, we analyze the shape of the attractor of the dynamics of the aeroelastic system and the Duffing oscillator. Measurements are obtained by simulation at only one location along the panel. Damages of various locations, extents and levels are shown to be revealed by the attractor-based analysis. For the panel, the type of damage considered is a local reduction in the bending stiffness. For the Duffing oscillator, variations in the linear and nonlinear stiffnesses and damping are considered as damage. Most of the current studies of such problems are based on linear theories. In contrast, the results presented are obtained using nonlinear dynamics, and have the advantage of an increased accuracy and sensitivity.