Effect of hybridization on the impact properties of flax/basalt epoxy composites: Influence of the stacking sequence

The effect of stacking sequence on the impact damage mechanisms and the matrix-fiber dependent properties, such as flexural and interlaminar strength, of epoxy hybrid basalt/flax composites has been experimentally investigated. The basal and flax fabrics have been appropriately selected with approximately the same areal weight and stacked in the same number in three different symmetrical analysed configurations to manufacture composites with comparable conditions regarding fibre content by weight. No influence of fibre sequence was observed for the flexural modulus, whereas some differences were exhibited by the flexural and the interlaminar shear strength depending on the resin content. The impact tests were carried out at penetration and different energy levels. After impact, indentation measurements have been performed by a confocal microscope to get information on the damage propagation and characteristics that resulted affected by the hybridisation type and by the impact energy. The results evidenced the relevance of the stacking sequence in the composite design to meet specific requirements.