Intra-tow micro-wrapping for damage tolerance

Micro-warpping of sub-scale fibre bundles with thermoplastic fibres has been explored for improved intra-tow hybridisation in comparison to traditional commingling process. This paper investigates matrix toughening of thermoset composites with thermoplastic fibres delivered through textile preforming and hence does not adversely effect resin viscosity during the infusion process. Tow-scale thermoplastic fibres appear to diffuse cracks from inter-laminar to intra-tow due to relatively weak interface, and at the same time protect the reinforcing fibres by acting as elastic foundations during impact loading. In this paper, two hybridisation methods, traditional commingling and novel micro-wrapping, have been compared for assessing the impact damage performance of thermoset composite laminates. It appears that micro-wrapped laminates exhibit better impact and damage tolerance performance than the commingled composite laminates due to the smaller impact induced damage areas and better PP fibre distribution. Improved thermoplastic fibre distribution in micro-wrapped tow architechture has been shown to improve impact damage tolerance through mechanisms of fibre cushioning and intra-tow crack dispersion. [Display omitted]