Influence of Braiding Angle on Multiple Impact Damages of 3-D Braided Composite along Longitudinal Direction

This paper reports deformation and damage evolutions of three-dimensional (3-D) braided composite with different braiding angles under multiple impact compression along longitudinal direction. Braided composites with braiding angle of 15°, 26° and 37° have been prepared for the compression tests. The impact compression test was conducted on a split Hopkison pressure bar (SHPB) along longitudinal direction. A high-speed camera was used to record damage development. A meso-scale finite element model has been established to simulate damage processes. The results show that the damage of composites occurs mainly in the first three impacts. For the 15° sample, damage of yarns and interface dominates the failure mechanisms at the first impact. For the 26° and 37° samples, the resin fracture and interface de-bonding lead to compressive failure at the first impact. Breakage and dislocation of yarns occurred for 15° sample during the subsequent two impacts, whereas it still keeps good structural integrity for 26° and 37° samples. The angle between adjacent yarns increased for the 26° sample and the yarns just tightened each other for 37° sample. Ductile damage is the primary damage mode for both yarns and resin during the multiple impacts.