Dynamic performance of self-sensing epoxy resin for aerospace structures

To meet the demand, especially of the aerospace field, of more and more advanced materials, more intense studies are being carried out on carbon-fiber reinforced composite materials. CNTs reinforcements allow for modulating the characteristics of a polymer matrix composite making it also suitable for more extreme operating conditions and resistant to environmental damage. The advantages of carbon nanotube reinforcement are many. They allow to improve the mechanical characteristics of the composite. The most relevant aspect, however, lies in the electrical properties that make these composites suitable for the design of self-sensing materials. In other words, composite materials reinforced with CNTs are used as sensors as well as structural materials and this is a highly sought after goal in recent times. Electrical techniques are the non-destructive way to monitor damage in composites subjected to static and dynamic loads. However, this approach is not applicable to composites where the fibers are non-conductive, such as glass and aramid fibers. Damage detection through conductivity measurements offers many advantages when compared to traditional glass fiber optic sensors. In fact, because of their high cost, it is not possible to create a dense network of these fibers to inspect large parts of the composite and especially if the damage spreads in the material without crossing the fiber could also not be detected. Therefore, the reinforcement with carbon nanotubes is the best way to go under the many aspects described. As part of an intensive research activity aimed at studying the performance of innovative smart resins, the authors will show in this article the outcomes related to some of their dynamic properties.