Monitoring experiment and simulation on solidification of DNAN based melt‐cast explosive with FBG sensors

Abstract In order to obtain the change rule of the temperature field and the mechanism of defect formation during the solidification process of melt‐cast explosive, the temperature field change data were tested during the solidification process of DNAN based melt‐cast explosive by using an arrayed spatially distributed Fiber Bragg Grating (FBG) temperature sensor device. The temperature field variation during the solidification experiment was obtained under the condition that the cooling rate of the boundary water‐bath temperature was 0.2 °C/min. On the basis of the solidification experiments, the macroscopic solidification process of small‐caliber grenade at different boundary cooling rates was simulated using ProCAST software. The simulation results show that when the boundary cooling rate is 0.2 °C/min, the temperature fields during the solidification process of DNAN based melt‐cast explosive are in good agreement with that of the experimental monitoring points; the size of the melt‐cast charge defects decreases as the boundary cooling rate becomes smaller; and the location of the charge defects is closer to the tail of the grenade as the cooling rate decreases. In addition, a mesoscopic model of DNAN based melt‐cast explosive was established in the paper. At the mesoscopic level, the generation, formation, and evolution of charge defects in DNAN based melt‐cast explosive during solidification were investigated. The study results provide theoretical guidance for the formulation design and process optimization of DNAN based melt‐cast explosives, as well as for improving the charge quality of ammunition.