Finite Element Modeling of Ballistic Impact on Kevlar 49 Fabrics

Abstract

This paper presents an improved material model suitable for Kevlar 49 fabric which was implemented into the commercial explicit Finite Element (FE) software LS-DYNA through a user defined material subroutine (UMAT). The fabric constitutive behavior in the current material model was obtained from new experimental data in the principal material directions (warp and fill) under static loading. Two different modeling configurations, i.e. single FE layer and multiple FE layers were used to simulate the ballistic tests conducted at NASA Glenn research center. Both the shear properties of the fabric and the parameters used in Cowper-Symonds (CS) model which accounts for strain rate effect on material properties were optimized to achieve close match between the FE simulations and experimental data. The residual velocity of the projectile, the absorbed energy by the fabric after impact, and the temporal evolution and the spatial distribution of the fabric deformation and damage were closely examined. Sensitivity analysis was carried out to study the effect of the failure strain of the fabric and the coefficient of friction on the simulation results.

A review on the mechanical performance of three-dimensional warp interlock woven fabrics as reinforcement in composites

“…[7] have achieved experimental testing and theoretical modeling regarding the tensile behavior of the 3D angle-interlock woven (3D-A) fabric under high strain rates. Before this study, high-strain rate tensile tests about woven fabrics only confined to 2D woven fabric structures, especially on plain woven fabric, have been reported in several literature [76–78]. From Figure 4, it could be found that the tensile fracture mechanism of the 3D-A fabric under quasi-static loading was different from that under high-speed condition.…”