Effect of hybridization on the failure mechanisms of thin/thick hybrid carbon/glass fiber-reinforced composites under flexural loading

In this study, the effect of inter-ply hybridization on flexural properties and the hybrid effect exhibited by thin and thick carbon/glass fiber reinforced hybrid composites is investigated. Under flexural loading, the multi-scale damage mechanisms demonstrated by thick laminates are compared with their thin counterparts using optical fractography and acoustic emission techniques. Moreover, digital image correlation is used to monitor the through-thickness strains in thick composites. Results showed that upon the addition of glass fibers, the failure strain of thick all-carbon (AC) laminate is improved by 89% with a hybrid effect of 65%, and hybrid samples show higher flexural strength than AC specimens. Substituting top/bottom carbon fibers with glass fibers in thick AC laminates resulted in dissipation of bending stress through the thickness of laminates, thus actively delaying the instantaneous global failure. Compared to non-hybrid specimens, failure paths of thick hybrid composites were predictable and repeatable.