Detonation product equation of state for overdriven detonations in triaminotrinitrobenzene-based plastic-bonded explosive

Overdriven detonation waves with non-stationary, high-pressure states can be produced by high-velocity impacts or by converging detonation waves. A precise equation of states (EOS) of the detonation products is essential to evaluate detonation performance and working capacity. The Jones-Wilkins-Lee (JWL) EOS and its modified forms have an uneven ability in describing the states of detonation products; furthermore, the accuracy of the calculated sound speed is inadequate. This problem is solved by an improved EOS, which is presented by introducing a variable Grüneisen coefficient within JWL. First, the Hugoniot parameters are calculated based on JWL, Jones-Wilkins-Lee-Lee, and Jones-Wilkins-Lee-Tang, and the maximum errors in the prediction of the sound speed are all significant, ranging from 5% to 15%. An excellent agreement is obtained using our modified JWL EOS for Hugoniot pressure over a wide range from initial pressure to 90 GPa, and in the meantime the sound speed is calculated more accurately, with the maximum error being reduced to 2.14%. Then, an experiment of the head-on collisions of detonation waves is carried out to assess the viability of our optimized EOS for characterizing the dynamic evolution of the overdriven detonation process. Furthermore, the hydrodynamic code is modified to incorporate the improved EOS and the numerical simulation is implemented. A comparison between the numerical results and the experimental data confirms the applicability of the improved EOS, and it indicates that a more accurate EOS is obtained for the description of the overdriven detonation phenomenon.