Double casing warhead with sandwiched charge to produce multiple fragment groups for sequential hits: Concept and analysis of fragment velocity.

• A novel fragment warhead with double casings sandwiched charge is proposed. • The different fragment velocities of each casing were measured by flash-radiography. • A formula was established to predict the fragment velocities of each casing. • The formula shows good agreement with the experimental and numerical results. • The fragment velocities of casing are affected by the size of the charge and casing. This work introduces a novel fragmentation warhead that can produce two groups of fragments with different velocity characteristics and strike the target sequentially. The two groups of fragments come from two separate casings in one warhead, and the different velocities of fragments from different groups are attained by having a charge compartment sandwiched between the two casings in the warhead. A theoretical analysis formula is established to predict the maximum velocity of fragment from each casing based on energy balance. The results of X-ray radiography experiment and 3D smooth-particle hydrodynamics numerical simulation indicate that the proposed formula is accurate and reliable in calculating the fragment velocity as long as the thickness of the inner casing is less than 30% the radius of the inner charge. The fragment velocities of warheads with different structure are further analyzed, and the results show that the fragments of the two casing exhibit greater disparity in their maximum velocity when more charge is packed in the sandwiched compartment instead of enclosed in the inner casing. [ABSTRACT FROM AUTHOR]