Mechanical behavior and damage degree of hybrid glass/carbon composites at low temperature

Hybrid composite samples with different carbon and glass fiber layers arrangement were produced by resin transfer molding (RTM) in an attempt to disclose the effects of low temperature on their flexural and low velocity impact behavior. Flexural tests were carried out at T = -50 degrees C and the failure modes were examined, while impact tests, always at T = -50 degrees C, were performed at penetration and at indentation in the range from 10 J to 30 J. The damage extension was accurately evaluated by ultrasonic non-destructive testing. The results were then compared with the room temperature ones obtained in a previous paper to highlight the influence of the temperature. The compression after impact tests were carried out at room temperature for samples previously impacted at both room and low temperature to assess the damage tolerance of the different hybrid configurations. Stacking sequence was found to govern both the flexural and impact behavior of laminates. At low temperature, the flexural strength and modulus values improved over the corresponding room temperature values irrespective of the stacking sequence, while an easier damage propagation and less residual strength were detected in dynamic loading.