The Ballistic Impact Response of Flexible Composite Body Armor

Abstract

This paper presents results from an in-house, finite-difference (FD) code to model ballistic impact into flexible composite body armor. The code, written in MATLAB, runs well on a high-end PC. The version we consider in this paper models the postimpact, pre-failure behavior of non-woven, cross-plied sheets made from UHMWPE yarns (e.g., DSM Dyneema®) in a polyurethane matrix at low volume fraction. This version can also model crimp imprinted in an up-down diamond pattern. Possible projectiles are right-circular cylinders (RCC) and spheres, though we focus on the former in this paper. We first review some assumptions regarding the element structure of the model where a single sheet is treated as a flat 2-D network of discrete, pin-jointed yarns and each node represents a non-sliding, yarn crossing point. We then adapt this model to apply also to a much thicker panel and then present various results, in graphical form, to illustrate the richness in behavior that the model captures.