Short-beam shear of nanoprepreg/nanostitched three-dimensional carbon/epoxy multiwall carbon nanotube composites

The effect of out-of-plane stitching and the addition of multiwalled carbon nanotubes on the short-beam shear properties of carbon/epoxy composites were investigated. Stitching influenced the short-beam strength of carbon satin and twill fabric composites, where the stitched satin carbon/epoxy composites showed improved short-beam properties compared with the unstitched satin carbon/epoxy composites. In general, stitching and MWCNTs addition enhanced the short-beam strength of the composite. The fracture of the composites generally exhibited as a combination of lateral total matrix cracking, warp fiber breakage and interlayer opening. In addition, all the structures experienced angularly sheared catastrophic through-the-thickness layer breakage. It was also shown that delamination was largely restricted in stitched and nano-added composites when compared to the unstitched samples. It can be concluded that nanostitching could be considered for improving short-beam strength properties of the composite.