Desensitization by pre-shocking in heterogeneous explosives and its numerical modelling

Desensitization caused by pre-shocking in heterogeneous explosives is discussed. The aim of this study was to find a simple numerical model that could reproduce the important features of previously reported shock desensitization experiments. After reviewing the previous experimental results and modelling efforts, an extension of the Lee-Tarver reactive flow model is proposed. The proposed desensitization model is based upon the experimentally determined desensitization criteria for explosives. The additional parameters required for this extension can be calibrated by experiment for a typical explosive. The new model has been implemented in the hydrodynamic code LS-DYNA as a user defined equation of state, and is now available to simulate various kinds of situations involving explosives up to the limits and capabilities of LS-DYNA. Desensitization by pre-shocking in double shock experiments, reflected shock and detonation quenching experiments have been studied using the new model, and the results were found to be in qualitative agreement with the experimental results reported in the literature.