Passive ultrasonic sensing for NDT and SHM

This keynote presentation will cover passive methods for ultrasonic NDT and SHM. These methods apply to cases where the test structure is subjected to uncontrolled excitations (such as from ambient loads) or to a limited number of controlled excitations. In these cases, proper analysis of the reception signals can reveal surprisingly accurate information from array analysis, such as imaging of internal defects. The effort here is to obtain as much information as possible from the receiver signals while exploiting at a minimum the excitation signals in the beamforming process. Examples will be shown for NDT imaging of holes in an aluminum block via plane-wave beamforming and SHM of a composite wind turbine blade via Matched-Field Processing imaging.