Numerical investigation of explosive bare charge equivalent weight

Peak overpressure and impulse are the most important parameters in the explosive performance estimation. Available models commonly consider trinitrotoluene explosive as the standard charge. In this article, the trinitrotoluene equivalency factor is studied through verified one-dimensional numerical simulations. The equivalency factors for impulse and overpressure are different and found to be constant with the scaled distance (3–40 m/kg^1/3), which means that a unique value for the equivalency factor is suitable for the equivalency factor calculation for each distance. Comparison of the equivalency factor with available models shows that it strongly depends on the internal energy ratio of the explosive in interest, relative to trinitrotoluene, and a new formula for equivalency factor for overpressure is proposed. A verified simulation method is presented in which the explosive is modeled with an equivalent “air bubble” with the same internal energy and ideal gas equation of state. A new approach using the energy flux density calculation is presented to calculate the equivalency factor for impulse and overpressure from a single gauge measurement of overpressure-time history, at a specific distance.