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Research Highlight

A scalable route to self-sensing composites

Next-generation fiber-reinforced composites may monitor their own structural health, detect damage, and issue early warnings. When enough electrically conductive fiber is embedded in a polymer matrix, the bulk composite becomes electrically conductive. Semiconducting nanoparticles coating the fibers can disrupt this electrical conductivity in response to stress, such as an airplane wing flexing excessively and causing crack formation.

Researchers utilized a roll-to-roll process to coat electrically conductive carbon fibers with semiconducting silicon carbide nanoparticles—demonstrating a scalable method to make reinforcing fibers for composite applications requiring strong, lightweight and self-sensing materials.1 The nanomaterial-embedded carbon fiber composite is stronger than other fiber-reinforced composites and imbued with the new ability to monitor its own structural health, allowing detection of subsurface damage and excessive stresses for early warning before catastrophic failure.

Researchers loaded spools of carbon fiber onto rollers that dipped it into nanoparticle-laden epoxy and ran it through an oven to set its coating. Then they made fiber-reinforced composite beams with fibers aligned in one direction. They tested the structures’ electrical resistance in response to stress, quantified the composites’ mechanical strength, and evaluated the composites’ ability to dissipate energy. They found that all 10 nanoparticle concentrations had enhanced energy dissipation (by 65 to 257 percent), which benefits structural applications by helping to mitigate vibrations and absorb impacts. A concentration of 40-50 weight percent (with respect to the epoxy coating) optimally increased mechanical strength and enhanced structural health monitoring sensitivity simultaneously.

The new process offers a route to high-volume, continuous-throughput fiber coating for fabrication of novel composite materials for commercial deployment.

1Christopher C. Bowland, Ngoc A. Nguyen, and Amit K. Naskar. "Roll-to-Roll Processing of Silicon Carbide Nanoparticle-Deposited Carbon Fiber for Multifunctional Composites," ACS Appl. Mater. Interfaces 10 [31], 26576-26585 (2018). DOI 10.1021/acsami.8b03401

ORNL's Laboratory Directed Research and Development Program supported the research.