Sympathetic reaction responses of cylindrical charges under blast and fragment loading

Accurate prediction of sympathetic reaction in cylindrical charges is essential for ammunition safety design. However, the underlying mechanisms involving near-field coupled loads remain inadequately understood. This study employs a combined experimental and numerical approach to investigate the sympathetic responses of cylindrical charges subjected to the impact of detonation products and fragments. The results indicate that the near-field reflected loads of bare RX-1 cylindrical charges are primarily governed by the dynamic pressure of the detonation products. The inertial confinement provided by the casing significantly reduces the peak dynamic pressure compared with that of bare charges at an equivalent expansion radius. As the expansion radius increases, the number of fragments exceeding various kinetic energy thresholds initially increases and then decreases, whereas the total kinetic energy within the effective coverage area decays monotonically. For bare charges, sympathetic reaction is primarily governed by the dynamic pressure of the detonation products. In contrast, for cased charges, the dominant mechanism shifts from the integral impact of a fragment cluster to the coordinated impact of discrete fragments as the expansion radius grows. Compared with fragment clusters, the contribution of detonation products to sympathetic reaction shows a stronger distance dependence, leading cased charges to generate a wider region of graded reaction intensities than bare charges. This study clarifies the contribution of near-field loads to sympathetic reaction, thereby providing a critical basis for developing predictive assessment models.