Impact resistance of woven fabrics

A comprehensive model is presented to study the deformation of and damage to woven fabrics under small projectile impacts. The approach dynamically follows the strain wave propagation along each individual yarn away from the impact point. As in previous work, the mechanics of wave propagation is formulated in terms of impulse-momentum balance equations, which are solved at each fiber crossover using a finite difference technique. Our approach explicitly considers the various projectile characteristics (shape, mass, velocity) as well as all fiber properties such as denier, modulus, and tensile strength. Even more importantly, the model allows us to account for slippage of yarns at crossovers and within the clamps. In contrast to previous work, yarn slippage and fracture processes are described with a kinetic approach, which explicitly accounts for their dependence on impact rate. Our model results are in good quantitative agreement with published experimental data on single-ply fabrics. They also clearly indicate that yarn slippage through clamps-often seen experimentally-is responsible for some salient features observed in ballistic data.