Debonding Detection in Aerospace Stiffened Composite Structures Using Ultrawideband Electromagnetic Tunneling

This paper proposes a novel approach based on ultrawideband electromagnetic tunneling for detection of debonding in composite structures. The idea behind this approach is to place two transducers at the opposite ends of a closed section stringer and analyse wave propagation in the hollow structure to detect damage occurrence and severity. A preliminary experimental campaign is carried out at laboratory level to optimize the setup and define damage detection metrics in view of aircraft fuselage monitoring. Results show that tunnelling approach can be used to assess the presence and severity of defect when air leak is present because wave field gets altered. In particular, microwaves in the frequency band from 4-8 GHz are mostly sensitive to the defect. In addition, damage metrics allow quantifying the damage occurrence and discerning noise in measurements from actual debonding.