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

Unidirectional (0°) 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 °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 °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.