Effect of temperature on low velocity impact damage and post-impact flexural strength of CFRP assessed using ultrasonic C-scan and micro-focus computed tomography

The effect of temperature on the low velocity impact resistance properties and on the post-impact flexural performance of CFRP laminates were studied. With this aim, 150 x 75 mm cross-ply carbon fibre/epoxy laminates with a [0/90/90/0](2s) layup, therefore with a total of sixteen layers, were impacted at ambient temperature (30 degrees C) and at elevated temperatures (55, 75 and 90 degrees C) at a velocity of 2 m/s using a drop weight impact tower. This was followed by flexural tests carried out at ambient temperature using a three-point bending rig. Damage assessment of impact and post-impact behaviour were carried out using ultrasonic C-scan and microfocus X-ray computed tomography (mu CT). Interrupted flexural tests using mu CT allowed delamination propagation to be observed. In general, lower projected damage was observed at elevated temperatures, which resulted also in a possible hindrance to delamination and shear cracks propagation during impact and in a greater amount of retained flexural strength after impact. (C) 2014 Elsevier Ltd. All rights reserved.