Influence of the shape of the explosive charge on blast profile

When an explosive charge is fired, the nature and mass of the explosive are the only parameters of importance usually considered. The shape however, also plays a major role in the effect of an explosive charge. Knowledge of shape effect can be important before the use of the explosive (in order to create a maximum effect with a given mass of explosive), or in post-explosion damage assessment. The shape effect however is only significant within a certain range from the charge. At longer distance, the produced blast wave tends to be spherical. The shock wave parameters studied in this work are the peak overpressure and the first positive impulse. A series of numerical test has been performed in order to determine the range of influence of the charge shape. Different locations of initiation were compared. A hemispherical charge was point detonated at its centre whereas a cylindrical shape was detonated at the centre of an upper or lower plane. Numerical simulations of near field burst were conducted using LS-DYNA software. During numerical tests a pressure fields were determined for different shapes of explosive charges as well as the pressure waveforms at points located 1000 mm from a centre. Additionally, reference pressure history curves from LOAD_BLAST_ENHANCED procedure were calculated.