High velocity impact on NCF reinforced composites

In the current paper, a series of high velocity impact tests using ϕ50 and ϕ25 mm ice spheres and 0.32 g granite stones on non-crimp fabric (NCF) composite plates are reported. The impact tests were performed using an air gun and velocities between 100 m/s and 199 m/s. The impact events were monitored using a high-speed camera, with a 20 million frames per second capacity, as well as by a displacement transducer for out-of-plane displacement measurements of the impacted plates. NCF composite plates of two different thicknesses were impacted. The composites were manufactured from carbon fibre and epoxy resin by vacuum infusion.Engineering type models were employed to predict impact response and impact damage formation. Comparison between predicted and resulting damage for the impact test validates the application of a semi-empirical model for predicting impact velocity thresholds for damage formation. Analytical models relying on the assumption of solid impact bodies cannot be employed for these types of impact.