Shockwave characteristics of thermobaric explosive in free-field explosion

The energy release process and damage characteristics of thermobaric explosive (TBE), a non-ideal explosive, differ from those of a normal explosive. In the present work, free-field explosion experiments were done to study the shock wave characteristics of TBE. The typical TBE grains and TNT grains with different magnitude order were tested and the shock wave parameters of TBE and TNT were obtained and fitted following the explosion similarity principle. Then a comparative research of TBE and TNT was done to show the characteristics of TBE. The results show that the peak pressure of TBE isn't obviously advantageous compared with that of TNT because it is only slightly higher than TNT at middle and far field. The positive phase time and impulse are related not only with the shock wave intensity and propagation distance but also with the explosive quality, so the specific impulse and specific positive phase time were studied. The correlation of the specific positive phase time between TBE and TNT is not definite. The specific impulse of TBE is higher than that of TNT at the same contrastive distance. When it is less than 2 m/kg^1/3, the specific impulse of TBE is 2 times that that of TNT. The curves of the peak pressure and the specific impulse was introduced to describe the characteristics of the shock wave, showing that the specific impulse of TBE is larger than that of TNT under the same peak pressures. When the peak pressure is between 20 kPa to 50 kPa, the damage degree is below middle level but when the specific impulse of TBE is 40%-60% higher than that of TNT serious damage is generated. As an important damage factor in the free field explosion, the impulse should be taken into account when evaluating the power of TBE.