Investigation of the effects of cooling temperature on the residual stresses of CFRP composite cylinders

Abstract

The well-established benefits of compressive residual stresses over the fatigue lifetime constantly motivate research efforts on the manufacturing process optimization. In present study, the focus is on the cooling temperature of composite materials after curing process. All samples were fabricated using ML 506 epoxy resin and carbon fiber T300. The specimens were cured for 4 hours at 100℃. After curing, two different cooling temperatures were considered. Some cylinders were cooled at room temperature (25℃) and other ones were cooled at a refrigerator with the temperature of 0℃ for two hours. The non-uniform residual stresses of CFRP composite cylinders which have been made by filament winding were determined using slitting method. The results show that the specimens which have been cooled at room temperature (25℃), underwent considerable tensile stresses in outer surface. While, the specimens that cooled at refrigerator (0℃), experienced less tensile stresses in outer surface, but noticeable compressive residual stresses in inner layers.