Safety of high explosives under low velocity impact: experiment, ignition criterion and numerical prediction

In this paper, experiment and numerical simulation were conducted to evaluate the safety of high explosive under low velocity impact. Specimen size effects on impact-induced reaction of high explosives have been experimentally studied in Steven test. In order to investigate the specimen size effect under different impact tests, the effective volume of explosive charge and the critical specific mechanical energy were introduced to analyze the impact sensitivity of several PBXs. The results show that, with the increase of effective volume, the critical specific mechanical energy needed for explosive ignition decreases and tends to reach a constant value. A new ignition criterion in terms of effective plastic work and specific plastic power was proposed to predict the ignition of explosives under low velocity impact. To evaluate the validity of this ignition criterion, the ignition threshold velocities of PBXs under Steven test was predicted, as well as the modified drop weight test, Susan test and Spigot test. The predicted results show a good agreement with experimental results.