A wavelet-based, distortion energy approach to structural health monitoring

A method for quantifying damage-induced distortions to the vibrational response of an experimental plate is presented. By examining a wavelet representation of the difference in strain response between the damaged and the undamaged structures, the distortion energy may be computed on multiple timescales. This feature is tested in its ability to detect both the presence and the location of degradation of the plate. In addition, the effects of competing excitation mechanisms, including the outputs of Lorenz and Rossler systems, as well as a 0-225 Hz Gaussian noise are studied. The results indicate that the distortion energies, statistically speaking, are significantly higher under damaged conditions compared to those extracted under undamaged conditions, implying that the new distortion energy approach will yield adequate features for detecting the presence as well as possibly the location of damage in a structure.