On the Perforation Characteristics of Concrete Wall Induced by Annular Jet and Central EFP Combined Warhead

A combined warhead with annular jet and central explosively formed projectile (EFP), which can produce large holes on reinforced concrete wall, is designed to solve the problem of perforating large hole on the wall. To solve the problems of twisting and deflection in forming process of annular jet, the annular liner with variable wall thickness is proposed. The variable wall thickness of annular liner is realized by two eccentric circles, and the changing gradient of wall thickness is determined by eccentricity. The forming processes of annular liner with four different wall thickness gradients were analyzed through numerical simulation, and the numerical simulation of the annular jet and the central EFP combined warhead penetrating into concrete wall was carried out. The annular jet with better density also has a certain angle of expansion. The perforation capability of the combined warhead to the concrete wall was verified through test. The test results show that the combined warhead can produce a through hole with a diameter of more than 2.5 times larger than the diameter of charge caliber on the concrete wall.