Influence of ply blocking on tensile stiffness in woven flax–carbon hybrids

The influence of carbon ply blocking on tensile stiffness in interlaminar flax–carbon epoxy hybrids is studied through various lamination schemes of similar nominal fiber volume fractions. Finite element mesoscale analysis accounting for distortions induced during compaction in the thinner carbon plies as a result of crimp mismatch was conducted. These distortions are shown to undermine hybrid stiffness, the extent of which is less pronounced when plies are blocked due to fewer hybrid interfaces, denoting that higher stiffness is achievable with blocked carbon plies. Backed by experimental evidences, it is suggested that detailed analysis on hybrid stiffness should treat hybrid interface as an independent variable a priori, and that modeling tools for carbon–flax fiber reinforced composites should consider not only the nonlinearity of flax response but also the waviness of both fabrics.