On the other hand Simic et al in

On the other hand, Simic et al. in their paper describe the effects of compositions on the detonation properties and the parameters of the air shock wave front on a lightweight model of inhibitor of apoptosis proteins thermobaric explosives (TBE, 400 g) [29]. This investigation comprises 14 thermobaric explosive compositions containing HMX, AP, Al, Mg, HTPB (hydroxy-terminated polybutadiene binder) in different weight percentages. Theoretical and experimental densities and porosities of TBE charges and detonation velocities were determined. Depending on the content of explosive, binding and component compositions, as well as on the content of Mg/Al as a fuel, the basic parameters of the shock wave speed, overpressure (Δp), maximum pressure (Put)max and TBE pressure impulse values were determined at different distances from the explosion center. By using piezoelectric pressure transducers, examination of the thermobaric effect was performed by means of measuring overpressure in the shock wave front. The activation and the detonation of explosive charges as well as the expansion process of detonation products were filmed by a Phantom V9.1 high speed camera [29]. For the needs of investigation of the effects of composition on the detonation properties and the parameters of the air shock wave front, new compositions of cast composite thermobaric explosives have been developed having the mass fraction of components: 31–50% of HMX, 15–20% of HTPB-based binder, 21–30% of Al, 0–9% of Mg and 0–20% of AP (ammonium perchlorate). In the study 14 experimental TBE compositions were prepared. The influence of the compositions and the ratio between the components on the detonation properties and the parameters of the air shock wave were examined each time, on light-weight experimental models (~400g). The test results were compared with the parameters of the standard charge (HMX/Al/HTPB = 50/30/20). The maximum overpressure values at all measuring points were achieved with TBE-3 (45% HMX, 10% AP, 21% Al, 9% Mg, 15% HTPB) and the lowest ones with TBE-1 (50% HMX, 30%Al, 20% HTPB). At greater distances from the explosion center, small differences in the values of the maximum overpressure were recorded which were indicative of the influence of the composition on Pmax values which had the most pronounced value in the area nearby the detonation site. It has been obtained that all the compositions containing magnesium had higher values of overpressure as compared to the standard charge. All the new compositions have higher pressure impulses than the standard charge. Among these, the compositions named as TBE-3, TBE-7, TBE-12 and TBE-1b are outstanding. They all have a higher content of the explosive component, aluminum, and have combined with a greater percentage of magnesium. The TBE-3 composition possesses the most favorable characteristics of thermobaric explosive in comparison to the other investigated compositions. It is characterized with higher detonation velocity, higher overpressure and pressure impulse; thus it can be recommended as the composition of choice for further research along this line [29]. Also the effect of the composition of cast composite thermobaric explosives on their processability was investigated by Simic et al. [43]. According to the experimental plan, 10 different thermobaric PBX explosive compositions (containing HMX, AP, Al, Mg, HTPB binder in different mass percentages) were prepared by applying the casting technology. The content of three components was varied: thermosetting hydroxy-terminated polybutadiene binder (HTPB, 15–20 wt%), ammonium perchlorate (0–20 wt%), and magnesium participation in a total metal content of 30 wt% (i.e. 0–30 wt% of aluminum was replaced by pyrolitic magnesium). Both the impacts of composition and curing time on viscosity were examined. Then, how the changes of component content affect the viscosity-time dependence for the three (upper mentioned) components taken separately as well as combined was analyzed. The densities of the samples taken from different segments of explosive charges were determined according to the standard method MIL 286B, and then the porosities were determined as well [43].