Strain-rate Dependence of Electrically Modified Unidirectional Carbon/epoxy Laminates Under In-plane Tensile Loading

This experimental work aims to investigate the strain-rate effect on a unidirectional carbon fiber-reinforced epoxy laminate system with enhanced electrical conductivity under in-plane tension loading. The electrical modification, termed Functionalized Interlayer Technology (FIT), was realized through interleaving a ductile carrier surface-loaded with nano-sized electrically conductive silver nanowires (AgNWs). A benchmark analysis was carried out against a non-modified UD carbon/epoxy laminate with the intention of examining the influence of the modification on the mechanical properties of the material. High rate longitudinal tension properties, at around 180 s⁻¹, were assessed using a split Hopkinson tension bar (SHTB) along with a high-speed camera. In-situ strain mapping using Digital Image Correlation (DIC) technique was employed to monitor the in-plane strain distribution and failure process of the composite laminates. The findings, for both laminate arrangements, demonstrated an absence of strain rate dependency on the tensile strength, modulus, and failure strain values. With respect to the electrical modification, FIT resulted in a decline of 18.8% on the longitudinal tensile modulus of the UD carbon/epoxy laminates. The findings covered in this article, along with those of the authors’ previous publications [1, 2], present for the first time the influence of strain rate on in-plane tension, compression as well as mode II interlaminar fracture toughness of electrically modified carbon/epoxy laminate system.