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/m(2) and 134 kPam(0.5). Similarly, G(IIC) and K-II values recorded for hybridized specimens were 2,173 J/m(2) 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. (c) 2015 Society of Plastics Engineers