Dynamic behavior and mechanisms of high overload resistance in a novel melt-cast explosive

Melt-cast explosives, characterized by their uniform charge density and low ignition sensitivity, demonstrate exceptional resistance to high overload, rendering them highly suitable as main charges in high-velocity or hypervelocity penetrating warheads. Under non-shock loads, the ultra-high overload resistance is primarily governed by their dynamic response and the interaction of microscopic defects. In this study, a novel cast-cast explosive was designed and prepared by incorporating 3-nitro-1,2,4-triazol-5-one as a high-energy, insensitive, and mechanically robust component. Split Hopkinson Pressure Bar, along with Brazilian Disc experiments combined with Digital Image Correlation, were conducted to characterize the dynamic properties of the explosive under medium strain rates. By comparing the microscopic structures of the explosive before and after the experiments, the damage and failure mechanisms under compressive and tensile stress states were clarified. A dynamic constitutive model was developed to describe the viscoelasticity, plasticity, and asymmetric damage evolution in tension and compression for the melt-cast explosive, with model parameters fitted based on the experimental results. The constitutive model was numerically implemented in LS-DYNA, and numerical simulations were conducted to verify the model's applicability and parameter validity. The dynamic properties and microscopic damage evolution under different dynamic tensile and compressive loads were analyzed. By comparing the dynamic performance and microscopic deformation mechanisms of typical pressed explosives, the results indicated that, although the melt-cast explosive exhibits some brittleness under dynamic loads, it maintains high compressive and tensile strength. From the perspectives of deformation characteristics, these findings provide important references for the design and engineering applications of high overload resistant melt-cast explosives.