This paper aims to explore the potential of carbon nanotubes (CNTs) in enhancing the structural capability and multifunctionality of carbon fiber composites in aerospace applications, primarily by focusing on interfacial applications. The conventional method of dispersing CNTs in a matrix is not fully efficient in exploiting the mechanical and multifunctional performance of CNTs. Hence, the use of CNTs at the interface or as a coating on the surface of carbon fibers has been suggested as a means of achieving multifunctionality, in addition to enhanced mechanical performance. The paper presents an overview of the various processes for growing CNTs on carbon fiber surfaces and examines the effects of CNT geometry and growth parameters on the properties of grafted fibers and their composites. Furthermore, it discusses the potential improvements in thermal and electrical conductivity achievable by incorporating CNTs at the interface, as well as the benefits of using CNTs as a sizing layer for carbon fibers, including enhanced fracture toughness and resistance to delamination.Highlights: Comprehensive study of interface engineering in carbon fibers and Carbon Fibre Reinforced Plastic (CFRPs) using carbon nanotubes (CNTs). Improved transverse mechanical properties and overall thermal and electrical properties. Multifunctional applications possible with the use of CNT. Both experimental and numerical studies reviewed.

This study investigates the effect of uncertainty in composite material properties on the cross-sectional stiffness properties, natural frequencies, and aeroelastic responses of a composite helicopter rotor blade. The elastic moduli and Poisson's ratio of the composite material are considered as random variables with a coefficient of variation of around 4%, which was taken from published experimental work. An analytical box beam model is used for evaluating blade cross-sectional properties. Aeroelastic analysis based on finite elements in space and time is used to evaluatethehelicopterrotorbladeresponseinforward flight.Thestochasticcross-sectionalandaeroelasticanalyses arecarriedoutwithMonteCarlosimulations.Itisfoundthatthebladecross-sectionalstiffnessmatrixelementsshow acoefficientofvariationofabout6%.Thenonrotatingrotorbladenaturalfrequenciesshowacoefficientofvariation of around 3%. The impact of material uncertainty on rotating natural frequencies varies from that on nonrotating bladefrequenciesbecauseofcentrifugalstiffening.Thepropagationofmaterialuncertaintyintoaeroelasticresponse causeslarge deviations, particularly in the higher-harmonic components that are criticalfor the accurate prediction of helicopter blade loads and vibration. The numerical results clearly show the need to consider randomness of composite material properties in the helicopter aeroelastic analysis.