Finite element analysis of the Advanced Combat Helmet under various ballistic impacts

In this research, ballistic performance of the Advanced Combat Helmet (ACH), which is currently used by the U.S. military, were numerically and experimentally evaluated. The ACH model was first developed and validated against existing test data in literature, which were obtained per the requirements of NIJ-0106.01 standard and the U.S. Army's V50 ballistic limit. The comparison of simulation results to experimental data showed that the developed ACH model was capable of predicting the ACH responses under ballistic impacts of 9-mm bullet and 1.1 g fragment simulating projectile. It is found that stand-off distances, impact point and curvature of impacted area are the main parameters that affect ballistic performance of the ACH. An open field experiment was also conducted for further investigation of ballistic performance of the ACH under higher caliber .223 rifle impact. Later, validated numerical model was used to compare with experimental data in terms of ballistic responses and damage pattern of the ACH. It is also found that although the ACH provides protection against 9-mm bullet impacts, it is inadequate under impact of .223 rifle impact.