Low-velocity impact response of carbon/epoxy laminates subjected to cold–dry and cold–moist conditioning

Woven carbon/epoxy laminate samples were subjected to low-velocity impact loading at energy levels of 15, 30 and 45 J. Samples were subjected to different moisture conditioning before subjecting to impact loading which included cold–dry and cold–moist for a period of 3 and 6 months. Impact parameters like peak load, absorbed energy, time to peak load and energy at peak load were evaluated and compared. Ensuing damage was measured on the impact surface as well as the back surface. Further, laminates were subjected to ultrasonic c-scanning to determine the impact damage. In general, samples subjected to conditioning exhibited better impact behavior in terms of the impact parameters. Damage sizes as determined from ultrasonic nondestructive evaluation (NDE) were comparable to room temperature samples except in the case of samples that were subjected to cold–dry conditioning for 6 months.