The effect of different curing conditions on hardness, thickness, and residual stress of carbon fiber reinforced epoxy composites

Abstract

In this study, an attempt has been made to optimize the curing process of carbon fiber reinforced epoxy laminates. The effect of four factors: curing temperature, cooling method, wetting method, and resin-to-hardener ratio was studied. Custom non-regular fractional factorial design was utilized to choose the combination of these factors levels. Vickers micro-hardness test was conducted to study hardness in all the specimens. Thickness measurements were taken. The residual stresses along fiber direction were measured using Timoshenko bending beam method. Box plots were drawn to understand data variability. ANOVA was used to analyze results. It was shown that curing at 180℃ or lower, applying furnace cooling, raising resin-to-hardener ratio, and avoiding wetting the bottom side have reduced data variability, lowered thickness, and residual stress.