Dynamic response of uncoupled thin-walled shell and fragments under internal explosive loading

The presence of an uncoupled outer shell, representing a flight platform, significantly influences the damage effect of a warhead by altering the velocity of driven fragments. The dynamic response of thin-walled cylindrical shells subjected to internal explosive loading and its consequential impact on the velocity distribution of preformed fragments were investigated in this paper. Integrated experimental and numerical studies were conducted. The fragment velocities were captured via high-speed photography and velocity measurement targets, while the shell expansion was monitored using Photon Doppler Velocimetry (PDV). Numerical simulations employing the coupled Euler-Lagrange (CEL) algorithm effectively replicated the explosion process. The results revealed that compared to an equal-mass coupled shell, the uncoupled one attained higher velocity while more substantially attenuating fragment velocity. The failure mechanism of the thin-walled shell (effected by its geometry) directly dictates the fragment acceleration history. The fragment acceleration process was characterized by three distinct stages, with a significant velocity loss occurring during the fragment-shell impact stage. Shell thickness and diameter were found to critically influence the magnitude and timing of this velocity loss respectively. These findings offer valuable references for predicting velocity loss of fragments and for the design and vulnerability assessment of uncoupled thin-walled shell under internal explosive loading.