Experimental investigation of thermal cycling effects on the transverse tensile properties of T800 carbon fiber/epoxy composites

The cryogenic propellant tanks often incorporate carbon fiber/epoxy composites into their outer structural layers, necessitating a thorough understanding of their mechanical properties when subjected to thermal cycling. In this study, the effect of thermal cycling on the mechanical properties of T800 carbon fiber/epoxy composites was investigated experimentally. Three different types of thermal cycling experiments were designed, followed by transverse tensile tests on specimens. The influence of cycling parameters, including the number of cycles and the temperature range, on the composites’ mechanical properties was examined. The results showed that the maximum tensile strength of the three groups decreased by 23%, 48%, and 39 %, respectively, while the corresponding reductions in elastic modulus were 18%, 23%, and 27%. These findings indicated that prolonged thermal cycling significantly degrades the tensile strength and elastic modulus of carbon fiber/epoxy composites. The fractographic analysis revealed more pronounced delamination in specimens subjected to a higher number of cycles, while severe fiber pull-out damage behaviors were observed under long-period thermal cycling conditions. This study offers preliminary insights into the mechanical performance of carbon fiber/epoxy composites under cryogenic-to-high temperature cycling, highlighting critical factors in their structural integrity.