Wavelet-based Wavenumber Filtering for Damage Detection with a Scanning Laser Sensing System

Abstract

This paper describes the use of wavelet-based wavenumber filtering for damage detection with a signal-frequency standing wave excitation on thin plate structures. Using a single, fixed frequency excitation from a mounted piezoelectric transducer, the full standing wave-field could be obtained using a Laser Doppler Vibrometer (LDV) with a mirror-tilting device. After scanning, a wavelet-based wavenumber filtering is performed to determine dominant wavenumber components, which could be used for indicative of structural damage. Mapping processes based on the wavelet-based wavenumber filtering is then carried out for damaged area visualization. To demonstrate the proposed techniques, several experiments are performed on thin walled structures with several different types of damage (corrosion, debonding). The results demonstrate that the techniques are very effective in localizing damage with the potential for the improved speed and the performance for damage detection.