Researches On Dynamic Behaviours Of High Explosives Under Magnetically Driven Quasi-Isentropic Compression

The dynamic behaviors of un-reacted explosives in wide pressure area are of great significance for us to study the mechanism of explosive initiation and chemical explosion safety. But solid explosives are high-energy metastability materials, when encountered external stimulation to the reactive threshold, a strong chemical reaction will occur. Due to shockless compression, small entropy increase and low temperature rise in the loading process, the magnetically driven quasi-isentropic compression technique can used to study the dynamic behaviors of un-reacted explosives in higher pressure than shock loading.In this paper, based on the magnetically driven quasi-isentropic compression technique, the quasi-isentropic compression of un-reacted explosives is realized in wide pressure area by using the laser displacement interferometer and optimizing the loading electrodes and the parameters of explosive samples. Specific studies are as follows:1. Based on the analyzing method of simple wave characteristics, the optimal isentropic loading pressures profile were calculated, under which no shock formed in 1.5mm and 2.0mm thick explosive samples. Using the discharge current waveform measured from the experimental apparatus CQ-1.5, the dimensional parameters of the loading electrodes and the isentropic compression techniques to explosives have been studied.2. Using the apparatus CQ-1.5 for isentropic compression experiments and the advanced technique of laser displacement interferometer, the quasi-isentropic compression of un-reacted explosives JO-9159 and JOB-9003 were conducted in 5GPa. The particle velocities of interface between the windows and the samples with different thickness have been obtained. The isentropes of the samples in 5GPa were calculated by means of one dimensional Lagrange method and backward integration method.3. The isentropic compression of JO-9159 and JOB-9003 were numerically simulated by one dimensional hydrodynamics code SSS. The simulatied particle velocities are in good agreement with experimental results. The particle velocities of interface between the windows and the samples with different thickness showed that shock wave was formed at 1.3mm thick deep in explosives. The strain ratios of the samples are in 105-106/s, and the strain ratio peak becomes narrower but higher when samples become thicker.