Electrical monitoring of structural health of laminated composite panels under compressive loading using carbon nanotube yarns

A 2 × 2 array of carbon nanotube yarns (CNTYs) was integrated into 10 cm × 10 cm laminated composite panels made of E-glass fiber weaves and a vinyl ester resin to electrically monitor structural health under monotonic and cyclic compression loading. An artificial debond was introduced at the center of selected panels to deliberately trigger localized damage, to better evaluate the damage location capability of the electrical technique using the CNTY array. In panels without debond, damage was localized near the load introduction (upper) edge. In panels with a circular debond, major fiber breakage and delamination occurred near the lateral vicinity of the debond. Real-time concurrent tracking of the CNTY array's electrical resistance combined with an algorithm for data reduction proved to be an effective diagnosis tool for detecting and localizing damage onset and progression, with only four CNTYs. This method accurately identified critical damage zones, which were confirmed by digital image correlation. These findings demonstrate the potential of CNTYs for non-invasive, real-time structural health monitoring without compromising mechanical performance, suggesting promising applications in aerospace, automotive, biomedical, and civil engineering industries.