Abstract:
Prediction of blast parameters for cased munitions always remains prime interest
for explosive experts and researchers in the field of energetic materials. These parameters
not only assist us in characterization of warhead (warhead design and safety analysis) but
are also the direct measure of performance/efficiency of warhead. These blast parameters
include initial fragments velocity of fragments, shock wave pressure, number/size of
fragments produced and spatial distribution of fragments. Determination of these
parameters is a challenging task due to high cost of arena testing (acquisition of firing
range and precise equipment like high speed cameras to measure fragments velocities),
adhering to the safeties involve in handling of explosives, time and lot of manpower/other
resources. Alternatively, numerical simulation techniques can be used to model the
blast/fragmentation behavior of cased munitions. Besides providing better understanding
of blast/fragmentation phenomena, these softwares can estimate blast parameters of
fragmenting warheads. In this study, Autodyn with SPH (Smoothed Particle
Hydrodynamics) solver is used to predict the blast parameters of a thick walled cylinder
filled with Composition B explosives. Multiple simulations have been carried out by
varying casing materials for same warhead. Comparative analysis of different casing
materials has been carried on basis of predicted blast parameters of fragmenting
warheads. On basis of simulation results, cast ductile iron has been recommended as an
alternative casing material to conventional steel casing on basis of its better
fragmentation characteristics, high end performance (higher strength, superior shock
absorption, corrosion/abrasion resistance etc.) and cost effectiveness. It has been
concluded that the casing material also affects the performance of fragmented warheads
vis-à-vis efficiency of cased munitions.
