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Shock Ignition and Growth of HMX-based PBXs under Different Temperature Conditions

Liu Rui, Han Yong, Li Ming, Jiang Zhihai, He Songwei

Central European Journal of Energetic Materials

2019

Vol. 16, no. 1

21--32

The Lagrange test was conducted to investigate the shock ignition and growth of HMX-based polymer bonded explosives (PBXs) under different temperature conditions. In this study, three temperature conditions, 25 °C, 80 °C and 120 °C were used. The pressure history values along the direction of the detonation wave propagation were obtained and presented as the characteristics of the shock ignition and growth. Manganin piezoresistive pressure gauges were used to measure the pressure. The results showed that the distance to detonation was clearly reduced as the temperature was increased. A distance greater than 9 mm at 25 °C was changed to less than 3 mm at 120 °C. In order to understand this phenomenon in more detail, the Lee-Tarver ignition and growth model was employed to simulate the Lagrange test, and the simulated pressures were compared with the measured pressures. The results demonstrated that the intrinsic mechanism of the phenomenon was that the high temperature changed both the equation of state of the unreacted explosive and the chemical reaction rate. It was remarkable that the parameter R2 in the model was reduced from −0.05835 to −0.06338, and the parameter G1 in the model was increased from 1.3 to 2.12.

Desensitization by Pre-shocking in Heterogeneous Explosives and its Numerical Modelling

Hussain T., Yan L., Fenglei H., Yi L.

Central European Journal of Energetic Materials

2016

Vol. 13, no. 2

357--379

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.