Open-Hole Size and Thermal Cycling Effects on Mass Loss and Surface Degradation of Polymer Matrix Composites

Degradation is a common problem for polymer matrix composites (PMCs) under low thermal cycling conditions. This paper investigates the effects of low thermal cycling on total mass loss (TML) and surface degradation of PMCs. Unnotched and open-hole specimens were weighed before and after low thermal cycling. The total mass loss and surface degradation of the specimens were studied over 250 cycles of 100˚C temperature difference. The experimental results showed that the mass loss linearly decreased during low thermal cycling. Also, it was found that laminates with smaller holes have higher percent mass loss than those with larger holes. Based on weight loss rates, a regression model is presented to evaluate the TML of laminated composite material samples. Also, under similar experimental conditions, the specimens exhibited 0.4% mass loss reduction after 250 cycles, and the incremental decrease of the hole diameter also decreased the TML. It was found that laminates with smaller holes have higher tensile strength variation than those with larger holes. The results showed that the incremental decrease of the hole diameter and number of cycles decreases the tensile strength of PMCs.