Abstract:
A finite element model was developed in LS-DYNA to computationally analyze the impact of a bullet against a multi-layer para-aramid textile package. The bullet was modeled as a deformable body, while the fabric package was represented as an interwoven yarn structure using a "mezzo-mechanical" approach to avoid modeling individual filaments. Remote areas of the fabric were simplified using a uniform orthotropic thin shell model. The study combined mezzo- and macro-mechanical approaches to reduce the model's complexity while simulating ballistic shooting experiments. Physical and numerical experiments were conducted to identify material parameters and validate the model, including determining lead material parameters by shooting a lead bullet into a lead plate, and determining para-aramid friction coefficients by shooting a bullet through a single fabric layer. The model's adequacy was validated by comparing results to experimental data on broken yarn patterns and bullet deformation. The research demonstrated that static material properties alone are insufficient for accurate modeling, and dynamic parameters adjusted based on strain rate are necessary. The final model was used to simulate a bullet's impact on a multi-layer fabric package, providing insights into the process and demonstrating the package's ability to stop a bullet.
