Two different modelling approaches for fabric composites subjected to ballistic impact

Fabric composites are widely applied in different fields and, in particular, have become a valid option in the realization of protective structures due to their low weight combined with high strength and stiffness. Finite element numerical models are an established method for the assessment and the optimization of the design of engineering structures. Two main approaches for the analysis of impacts on fabric composites are present in the literature. A macro-homogeneous approach considers the materials as an equivalent homogeneous medium with no distinction between the constituents. A meso-heterogenous approach reproduces the material microstructure and therefore its components are considered as different entities. The capacity of these two numerical models to model the ballistic impact of a real bullet against a panel made of plain weave Kevlar® 29 embedded in an epoxy matrix is compared in this study. The outcome of the comparison of the two numerical model is assessed using experimental data from actual ballistic tests. Quantitative results, such as the residual velocity of the bullet, as well as qualitative results, such as the damage morphology, are compared. The latter is especially important in case the impacted structure is multifunctional, aimed to protect as well as to carry load.