Improved impact behaviour of carbon fibre reinforced plastics by integration of multi-component non-woven veils

The resin transfer moulding process is a promising candidate to replace the energy intensive prepreg autoclave process. A disadvantage of resin transfer moulding is the poorer impact performance of the parts produced compared to prepreg autoclave parts. The impact behaviour can be improved by interleaf layers, which hinder the crack propagation. In this work, new multi-component non-woven veils are developed to improve the process and the produced composite. The non-woven veils consist of a low melting thermoplastic fibre as a binder and a high melting thermoplastic fibre, recycled carbon fibre or aramid for improved impact performance. Initially produced on a dry-laid nonwoven machine, the veils are then thermally fixed to ensure a consistent basis weight and improve handling properties. Finally, the non-woven veils are incorporated into a non-crimp fabric laminate. The mechanical performance of the laminates is tested using tensile, flexural and inter-laminar shear tests. Samples with interleaf layers show no critical reduction in properties compared to such without. In a second step, the impact behaviour is tested. The laminates are impacted at two different impact energies and the damage is analysed using ultrasonic C-scans and micro-computed tomography. The ultrasound scans show that the integration of the non-woven veil reduces the damage by up to 76%. The micro-computed tomography analyses show that not only the damage area is reduced by the integration, but also the damage through the laminate thickness, especially at high impact energy. Hence, the non-woven veil acts as an interlayer and improves the impact performance.