Modern defense missions increasingly demand weapon systems capable of rapid deployment and establishing wide-area protective zones. This study investigated the explosive canister opening process and fragment dispersion dynamics of 12.7 mm fragmentation warheads designed for machine gun platforms. Using LS-DYNA with an ALE-based fluid–structure interaction algorithm, the complete transient response sequence was simulated, from detonation initiation and structural failure to fragment release. Three fragment geometries (cylindrical, square, spherical) and three axial detonation positions were comparatively analyzed. Results reveal a progressive structural failure sequence and bidirectional axial motion of fragments. Square fragments achieve the highest stable radial velocity (~150 m/s) due to their larger pressure-bearing surface, outperforming cylindrical (~140 m/s) and spherical fragments (~120 m/s). The fragment closest to the initiation point consistently attains the maximum radial velocity. These findings provide theoretical support for the structural optimization and initiation design of small-caliber fragmentation warheads, thereby enhancing their short-range defensive effectiveness.
Hao et al. (Sun,) studied this question.