FE modeling of woven fabric at the fiber bundle level under ballistic impact

In previous studies, ballistic impact on the fabric panel was usually simulated at the yarn level, which failed to capture ballistic responses of fibers. This study aims to employ a finite element model based on fiber bundle level to investigate the influence of fabric architecture on ballistic responses. The ballistic performance of fabrics with different architectures was investigated first through ballistic tests. The architecture parameters including aspect ratio of the yarn cross-section and yarn crimp ratio were found to be the dominant factors, which were further investigated through finite element modeling. Finite element results showed that finite element modeling at the fiber bundle level can lead to an increase of frictional energy dissipation during ballistic impact. For the yarn cross-section shape, reduction of the aspect ratio was beneficial on energy absorption due to better fracture synchrony of fibre bundles under impact. The crimp yarn path had a negative effect on stress wave propagation. When yarns were interlaced, the yarn cross-overs in fabric have further hindered the stress wave propagation. In comparison with the low crimp fabric, the fabric with the higher crimp ratio possesses a wider transverse deformation area under impact. Correspondingly, in the high crimp fabric more yarns were involved in the transverse deformation, which resulted in higher energy absorption. However, high stress concentration on the high crimp yarns can result in premature failure of fibers at the impact area. Such results contribute to a further understanding of ballistic responses from different hierarchies of fabric during ballistic impact.