Multi-hit ballistic impact on S-2 glass/SC15 thick-section composites: finite element analyses

The effect of support spans on single-hit ballistic limit and the effect of pre-existing ballistic damage on multi-hit ballistic limit for two S-2 glass/SC15 composite laminate thicknesses (i.e. 13.6 mm and 20.5 mm) using 0.50cal fragment simulating projectiles have been experimentally investigated in a companion paper. The main objective of this paper is to simulate and correlate the multi-hit ballistic experiments using finite element analyses. One multi-hit ballistic impact scenario on two different composite laminate thicknesses is considered in the present analyses. Finite element model of the impact scenario is developed using three-dimensional solid elements and are solved using LS-DYNA and the progressive composite damage model MAT162. The MAT162 properties and parameters of plain-weave S-2 glass/SC15 composites used in the present simulations were validated in our previous work. Multi-hit impact cases are simulated by sequentially impacting the composite laminate with five different fragment simulating projectiles at five different impact locations at an interval of 200 micro-seconds. Good correlations of ballistic limit velocities between experiments and finite element analyses are obtained. In addition, finite element analyses provided time histories of projectile and laminate dynamics, and damage evolution and interactions for the multi-hit impact cases. Detailed simulation results and comparison with the experiments are presented.