Computational modeling of explosive-filled cylinders

A time-dependent, two-dimensional, finite-difference code can be used to model fragmenting cylinders. Strictly hydrodynamic treatment of the casing material generally overpredicts the final fragment velocity. A more definitive final fragment velocity is predicted when the casing material is treated as an elastic-plastic material, but the final fragment velocities occur at unrealistically high cylindrical expansion ratios. To remove some of these objections and, at the same time, model the casing motion more realistically, a gas leakage model has been developed to simulate explosive gas leakage around fragments after casing breakup. Comparisons have been made between code calculations and experimental data. The experimental data include different length-to-diameter ratios, natural and discrete fragmenting cylinders, different charge-to-casing mass ratios, and different initiation postures. The gas leakage model predicts definitive final fragment velocities in excellent agreement with the experimental data.