Combining one or more functional capabilities of subsystems within a structure can provide system-level savings, particularly for weight-critical applications such as air and space vehicles. Nanoengineering presents a significant opportunity for additional functionalities on the nanoscale without the necessity to modify shape, design, or load carrying capacity of the structure. Here, an integrated-multifunctional nano-engineered system was preliminarily studied in composite laminate structures. The study would support the exploration of a system designed to serve independent yet synergistic functionalities in life-cycle enhancements, energy savings during manufacturing, in-situ cure (manufacturing) monitoring, and in-service damage sensing. For the preliminary study, an integrated multifunctional composite (IMC) laminate was created via aligned nanofiber introduction into the composite interlaminar region and the laminate surfaces of Hexcel E-glass/913 unidirectional glass fiber prepreg. Various heights ranging from 10 - 40 μm-tall vertically aligned carbon nanotube (VA-CNT) arrays, as well as patterned and buckled VA-CNT architectures, were used to reinforce the weak interlaminar regions within the laminates showing a ~ 4 - 5% increase in short beam strength of VA-CNT reinforced specimens hence demonstrating interlaminar enhancement for life-cycle advancements. The same layers, being electrically conductive, can provide several additional multifunctionalities.

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For aerospace vehicles, where weight reduction is important, studies have been performed on composites to include different functionalities besides their primary structural function. Some of these functionalities include energy savings, self-health monitoring, ice protection system, and self-curing sensing capabilities, and have been demonstrated individually in carbon fiber reinforced polymer composites. Nano-engineering techniques enable integrating these functionalities in composite systems to add multifunctionalities with insignificant changes in dimension or weight of the composite system, while ensuring that the mechanical properties such as strength are maintained or enhanced. Here, glass fiber reinforced polymer composites are nanoengineered to add multiple multifunctionalities concurrently via hierarchical assemblies of vertically aligned carbon nanotubes. In this preliminary study, the nanoengineering of the composite suggests life-cycle enhancements via an increase in interlaminar shear strength.

Glass fibers are used in RRIM Urethane to pro vide dimensional stability and good physical properties- particularly impact strength. However, 1/16" milled glass fibers have the disadvantages of high cost (approximately 82¢/Ib.), anisotropic impact properties and difficult handling and process characteristics. Acicular type fillers, such as Wollastonite, provide tempting substitution possibilities because of lower price, isotropic impact properties and in herent easier handling. However, untreated Wollastonite grades provided inferior properties when compared to silane sized 1/16" milled fiberglass. Silane treated Wollastonite, G. Wollastokup 1100 0.5, has shown promise but falls short in the important area of impact.

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