Identification of damage in an aeroelastic system based on attractor deformations

Vibration-based damage detection is a powerful method of structural health monitoring, which is based on the identification of changes in vibration characteristics due to changes in material and/or stiffness properties of structures. Current such techniques are based mostly on linear approaches, whereas nonlinear methods still have certain difficulties in detecting the level and location of damage, especially in the case of high dimensional systems. One of the main reasons for these difficulties is the low sensitivity of current methods to small parametric variations. In this paper, we increase this sensitivity by exploiting nonlinearities. To explore the potential offered by nonlinearities in increasing sensitivity, results are presented for a two dimensional panel subjected to supersonic flows. The nonlinearity resulting from the coupling of stretching and bending of the panel is considered in the structural model. The damage in the panel is modeled as a local loss of bending stiffness (along the panel) and at the mounting points. The basis for the development of a method for detecting multiple simultaneous damages is presented. This method is based on probability density functions of sampled attractors of the dynamics. Exploiting nonlinear dynamics is shown to be powerful in detecting different damage levels and locations.