Effect of reinforcement continuity on the ballistic performance of composites reinforced with multiply plain weave fabric

Structural composites with doubly curved surfaces, including ballistic helmet shells, require the use of discontinuous reinforcements due to their limited mouldability. This paper reports on the effect of reinforcement continuity on the ballistic performance of composites made from multiply plain weave fabric. Composites reinforced by 20-ply Twaron® plain weave fabrics, both continuous and discontinuous (with 20 mm and 45 mm overlapping respectively), were produced using the vacuum-bagging method. The composites were subjected to perforation ballistic tests for performance evaluation. The damage morphology after impact was examined and characterised using through-transmission ultrasonic C-scan and X-ray computed tomography (CT). The ballistic results confirmed the superiority of the continuously reinforced composites as they absorbed up to 19.30% more impact energy, caused wider delamination, and exhibited more than twice the damage volume when compared to their discontinuously counterparts. Both ballistic test and X-ray CT results suggested that for the discontinuously reinforced composites, longer reinforcement overlapping length are associated to more effective ballistic protection. The findings are indicative for the engineering design of lightweight ballistic helmet.