Wave Scattering Phenomena for Health Monitoring of Hard-to-Inspect Defects <sup></sup>

Abstract

Doherty and Chiu reported on the potential use of propagating stress waves for monitoring fatigue crack development in a series of hard-to-inspect weep holes in the wing spar of an aging aircraft. New experimental evidence showed an interesting scattering phenomenon at the defect and demonstrated the ability to use this phenomenon to monitor the development of an upward developing fatigue crack. It was found that a scattered field can be used to highlight the presence of a source of a secondary wave mode arising from the interaction of the incident wave field with the defect. A detailed investigation into these observations will contribute to the creation of new basic scientific understanding of this phenomenon with the potential development of a novel and optimised approach for quantitative inspection of hard-to-inspect regions in a structure.