The Effect of Penetrator Geometry on the Dynamic Response of Woven Graphite/Epoxy Composites

The primary focus on this paper is to study the high energy penetration/perforation damage propagation of composite plates using the perforation split Hopkinson pressure bar. The objectives include: investigation of propagation of penetration and surface crack damage in the vicinity perforation threshold velocity; investigation of energy absorption and strain intensity profiling; and quantitative analysis of the interactive effects of penetrator geometry and sample thickness on the perforation damage of woven graphite-epoxy composite plates. The results show that strain rate increased with damage energy threshold levels and decreased with sample thickness from below to above the perforation limit velocity on the average. There was a significant difference between penetrator geometries on a specimen strain rate, and penetrator size other than shape was a more important factor. As the size of the penetrator increased, the perforation energy thresholds increased accordingly. Thus, for the same energy level, the larger penetrator delivered more energy to the target. The mode of perforation failure was localized with obliquely shaped cracks for the woven specimens. It was conceivable that the cracks first initiate at the point of intersections of the weave and move in both directions. These results would provide some instructions in building, designing, and evaluating protective structures that undergo any penetration type of impact.