Abstract:
This paper details the development of a finite element model using LSDYNA to simulate the ballistic impact of a deformable bullet on a multi-layer fabric package made of para-aramid Twaron textiles. The model simplifies the multifilament yarns into thin shell elements and uses a combination of finely and roughly meshed zones to represent the fabric, with a tie constraint connecting the two. The purpose of this computational model is to simulate shooting experiments and test the ballistic strength of body armor, which can facilitate the design of multi-layer packages. The model accounts for the real geometries and deformability of the bullet and the fabric. It incorporates different bullet models, including a 9mm full metal jacket bullet with a brass shell and lead core, and a lead bullet, both generated using TrueGrid. The materials are defined as elastic-plastic, and the study highlights the importance of using dynamic material properties that account for strain rate, as static properties alone are insufficient for high-velocity impact simulations. The authors performed a series of physical and numerical experiments, including shooting a lead bullet into a lead plate, to identify and validate material parameters like yield stress and hardening models to ensure the model's results are physically adequate and close to reality. The findings show that the fabric package's ballistic strength is primarily dependent on the number of layers and the friction coefficient between the bullet and the fabric layers.
