Research - Analytical Model for Fabric Impact

Gaurav Nilakantan

Research—

Analytical Model for the Ballistic Impact of Yarns and Fabrics

Two analytical models are developed for the tensile and transverse impact response of yarns and fabrics. The transverse impact model is based on the conservation of energy and momentum at the fabric-projectile centerline and uses a modified version of Smith’s Velocity-Strain formulation. The model is first tested on a single yarn and then extended to a single layer of fabric using a special extrapolation method. The propagation of the faster moving longitudinal strain wave and slower moving transverse displacement wave are tracked at each time instant. The model is capable of predicting the instantaneous projectile velocity, fabric internal and kinetic energy, fabric momentum, and time instant of failure. The model can also track the development of stresses and strains in the yarns as a function of the wave propagation. Failure is incorporated using a maximum tensile strain to failure. The analytical models are implemented in MATLAB and compared to numerical simulations set up in LS-DYNA.