Abstract：Improved ballistic simulations were developed for homogeneous steel sheets against small-caliber bullets. The simulations analyzed the influences of the contact-force penalty function parameters and contact friction coefficients on the contact interface state and ballistic limit velocity. The inconsistencies among computed ballistic limit velocities predicted by different partitioned parallel systems were investigated statistically. The interface stiffnesses within the contact-force penalty function should be defined between different contact pairs rather than assigning an equal interface stiffness to all contact regions to improve the accuracy of the ballistic limit velocity. Different friction coefficients between contact pairs can seriously affect the computed ballistic limit velocity for thicker steel targets against armor piercing bullets. Further study is needed to determine the correct friction coefficients for multiple contact pairs. The exchange of regional data and the use of this data in different sequences make the partitioned parallel computations of repeated computation tasks inconsistent, which affects the ballistic limit velocities predicted by the parallel computations. Therefore, repeated calculations using the same model for the same impact velocity are needed to obtain reliable ballistic limit velocity statistics.
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