Numerical simulations of fabric shields for bulletproof vest: determining the number of sheets to withstand ballistic impacts

Abstract

The main contribution of this research is to develop a FE model for evaluating impact loading against fabrics. Although the fabric model has been studied by some authors, this article contributes with a FE model with a new material formulation which takes into account the stress-strain limit to simulate the fabric rupture. As a case study, the author uses a bulletproof vest impact analysis and determine the number of sheets necessary to resist the ballistic impact. A sophisticated numerical algorithm is used. New constitutive equations are developed capable to take into account the material damage, yield stresses and rupture limits. This is based on elastoplasticity theory, with an adaptation of the function related to the hardening of the material. With this, it is possible to control the limits of the permissible stresses on the yarn and coating of the structural fabric and accurately represent the physical behavior of the materials used. The elastoplasticity and damage theories are developed and, finally, a numerical algorithm is presented for the determination of stresses, displacements and material deformations.