Effect of braiding angle on dynamic mechanical properties of 3-D braided rectangular composites under multiple impact compressions

This paper reports dynamic mechanical behaviors of 3-D rectangular braided composite with different braiding angles under multi-pulse impact load. The composite materials were prepared with braided preforms which have braiding angles of 15 °, 26° and 37 °, respectively. Impact compression tests were conducted in split Hopkinson pressure bar. High-speed camera system was used to capture damage growth process and a meso-scale finite element model was established to investigate failure mechanisms. We found that the braiding angle has significant effects on damage development, failure mechanisms and ultimate damage morphogenesis. The braided composite with 15° braiding angle shows a linear elastic response at the initial stage of stress–strain curves until the peak load. After the peak load, the composite has brittle failure behaviors, while the composites with 26° and 37° braiding angles exhibit non-linear elastic response at the beginning stage of stress–strain curves and ductile failure mode after yielding points. The composites with different braiding angles demonstrated both distinguished damage development and final fracture morphology. In addition, load-bearing ratio of yarns in composite was also affected by braiding angles.