Numerical Investigation of Debris Impact on Multi-layer Kevlar Shield

The numerical simulations of hypervelocity impact on multi-layer dry Kevlar fabrics are presented in this paper. A macroscopic finite element model of Kevlar fabric is implemented with 3D solid elements and defined using homogenized properties. Simulations were performed with erosion model in ABAQUS software. The erosion model is used to evaluate the ballistic limit thickness of multi-layer Kevlar K29 and K49 fabrics when impacted by sub-millimetre steel projectile at a velocity of around 6 km/s. Four simulations were performed with 0.3 and 0.5 mm diameter projectiles for each fabric using coupled structural–thermal analysis. In a different multi-layer configuration, an aluminium projectile of 5.56 mm diameter was made to impact a 6-layer Kevlar KM2 fabric at two different velocities of 3.2 and 6 km/s. The model is also found to be significant in accurate prediction of its damage characteristics such as tensile cracking and fraying/unravelling of yarns. The transverse wave velocity is found to be dependent on thickness, i.e. number of layers. The above simulations results are in good agreement and have been benchmarked with the available experiments in the literature.