Effect of hybridization on the mode II fracture toughness properties of flax/vinyl ester composites

In this study, flax fiber reinforced and flax/basalt hybridized vinyl ester composites were produced and their interlaminar fracture toughness (mode II) behavior was investigated using the three‐point bend end‐notched flexural (3ENF) testing. From the results, the average of the maximum values for each group of specimen obtained for critical strain energy release rate G_IIC and stress intensity factor K_II for flax/vinyl ester specimens were 1,940 J/m² and 134 kPam^0.5. Similarly, G_IIC and K_II values recorded for hybridized specimens were 2,173 J/m² and 178 kPam^0.5, respectively. The results for the flax/basalt hybridized composites exhibited an improved fracture toughness behavior compared to flax/vinyl ester composites without hybridization. The cohesive zone modeling (CZM) was also used to predict the delamination crack propagation in mode‐II in laminated composite structures. After the experimental study, the 3ENF specimens were modeled and simulated using ANSYS. The CZM/FEA results were in reasonable agreement with the experimental results. POLYM. COMPOS., 38:1732–1740, 2017. © 2015 Society of Plastics Engineers