Abstract:
Environment assisted degradation in mechanical properties is a major concern for the integrity of
composites in structural applications. Experiments are performed to examine the efficacy of
carbon nanotubes (CNTs) to counter the adverse effect of environmental conditions on the
fracture toughness of carbon fiber/epoxy composites (CFRP). Composite coupons are exposed to
accelerated weathering cycle for varying durations. Experimental testing shows that the fracture
toughness degrades significantly after exposure to aging cycle. The addition of CNTs minimizes
the adverse effect of weathering. The comparable fracture toughness of 1000 hrs aged CNT
modified CFRPs with the unaged conventional CFRPs suggest that the advantages of CNT addition
persist even after exposure to prolong weathering conditions. Fractography analysis reveals that
the CNT induced toughening of epoxy improves Mode I and Mode II fracture toughness of conventional CFRPs. While the fracture in conventional CFRP is primarily at fiber/matrix interface,
textured microflow, larger sized cusp and matrix cracking are observed in CNT modified CFRPs.
