PZT piezoceramic nanofibers for impact localization in composite laminates

Structural Health Monitoring (SHM) of composite laminates often relies on embedded sensors, which can detrimentally compromise the material's mechanical integrity. In contrast, micro and nanomaterials have been shown to exert minimal impact on the mechanical performance of laminates while providing effective sensing capabilities for compressive, tensile, and tactile loads. Nevertheless, the detection of elastic wave propagation continues to depend on ceramic piezoelectric lead zirconate titanate (PZT) sensors. This study presents an innovative approach by integrating PZT nanofibers directly into the composite laminate structure, effectively combining the superior piezoelectric properties of PZT with the advantages of a nanostructured, minimally intrusive material. Specifically, PZT nanofibers are strategically interleaved and positioned at the corners of a rectangular glass fiber reinforced plastic (GFRP) panel (30 × 20 cm). Upon impact on the laminate surface, the high sensitivity of the PZT nanofibers enables the detection of elastic waves propagation, generating a piezoelectric signal that allows for precise impact localization through a triangulation algorithm. Compared with a traditional panel with commercial PZT disks interleaved, the nanostructured panel exhibits a higher impact localization error (2.50 ± 2.46 cm versus 3.74 ± 2.84 cm), while exerting less influence on its mechanical properties. Indeed, low-velocity impact tests confirm the superior impact resistance of the nano-modified laminate compared to its counterparts with traditional PZT sensors.