Simulation of Soft Projectiles Impacting Composite Targets using an Arbitrary Lagrangian-Eulerian Formulation

Methods for modeling the impact of triaxial braided composites with a gelatin projectile have been developed using the commercial explicit finite element code LSDYNA. An arbitrary Lagrangian-Eulerian formulation was used to resolve problems with numerical instability that were encountered in previous simulations based on a pure Lagrangian formulation. The LSDYNA MAT 58 material model and shell elements were used for the composite. Composite material properties were obtained from available experimental data and micromechanics calculations. The impact dynamics and penetration thresholds observed in the experiments were adequately simulated. The simulated contact forces between the projectile and composite material were useful for understanding the onset of penetration. The effect of boundary conditions on the penetration threshold was simulated using spring elements located at the boundaries. Simulations confirmed experimental observations that the penetration threshold is higher when slipping occurs during the impact. The impact simulations also show that the reaction forces at the boundaries of the half-ring are much smaller than for the flat plates, and so the boundary slipping will occur more likely during the flat plate impact case.