Structural health monitoring using active sensors and wavelet transforms

Health monitoring methods using active sensors (e.g. piezoelectric transducers) and wavelet transforms are being developed in the Department of Mechanical Engineering at the University of South Carolina. In these methods, wave propagation signals are collected using arrays of piezoelectric transducers placed on or embedded in a structure. The collected signals are analyzed using appropriate wavelet transforms. The final interpretation of the sensor signals is based on signal patterns uncovered by the wavelet transforms in correlation with elastic-wave propagation theory. A number of specimens have been instrumented and tested, which include simple steel beams and actual composite aircraft panels. Impact tests simulating low velocity impact by foreign-object have been conducted and will be used to illustrate the wavelet-based methods.