Non-destructive structural integrity testing of finite plates based on the wave scattering at defects with sub-wavelength size

摘要

This paper describes a technique to magnify the scattering of a wave at a defect by using the natural behavior of a structure. The fundamental physical principle of the detection strategy as well as the way to exploit this principle for detecting defects are explained. The influence of the parameters defect location, defect size and natural frequency selected, is investigated in a numerical example considering a 1mm thick A3 Aluminum plate. The proposed defect detection strategy is based on the measurement of frequency response functions at a very limited number of response locations and is therefore very easy to apply. Furthermore, an experimental validation of the detectability of a square 4mm through thickness defect is performed. Due to its simplicity and the low number of sensors necessary, the strategy explained in this paper allows the detection of a defect very rapidly.