Acoustic emission characterization of the temperature effect on falling weight impact damage in carbon/epoxy laminates

Unidirectional (0 degrees) and cross-ply (0/90) carbon-epoxy laminates were subjected to falling weight impact loading with energy of 2.17 J, therefore not producing visible damage, at different temperatures (30, 55, 75 and 90 degrees C). Post-impact flexural tests were monitored using acoustic emission (AE). Both for unidirectional and 0/90 laminates an increase in residual flexural strength and resistance to impact was observed up to 75 degrees C, while an opposite trend was noticed closer to the glass transition temperature of the resin. From AE results it was observed that temperature and orientation play a non negligible role in altering the nature and extent of the different damage modes, namely matrix cracking, delaminations and fibre failure. (C) 2013 Elsevier Ltd. All rights reserved.