Study of Blast Pressure, Velocity, and Mass Distribution of Controlled Fragments Caused by Cylindrical Warhead

The pre-controlled fragment technique refers to regulating the size of pieces formed by breaking the warhead with the specific mass of fragments which can enhance the lethality of the warhead. The lethal efficiency of high explosive (HE) warheads is a function of fragment velocity and mass of controlled fragments and their spatial distribution. Fragment velocity depends on the explosive and its density, warhead metal case and explosive mass ratio (c/m), detonator position, etc. This paper employs a three-dimensional numerical simulation using AUTODYN-3D to study the semi-preformed warhead's expansion and subsequent fragmentation process. This paper also presents fragment mass, velocity distribution, and blast pressure generated due to detonation. HE warhead diameter of 70 mm and a length of 147 mm with internal grooves have been designed and evaluated experimentally and carried out in numerical simulation. Warhead casing is made of Steel 4340, while Comp B is employed as the explosive. For the simulation investigation, we opted to use a single point of activation situated at the back of the warhead’s centre. Additionally, an experiment with the same configuration of casing geometry, explosive, and its initiation mechanism was conducted to evaluate fragmentation and mass distribution along with the velocity of fragments. The comparison of experimental and simulation results shows a difference of 5.6% for fragment velocity. The recorded peak overpressure values are found at 3 m, and 5 m are comparable with the analytically calculated values.