Mechanical properties of DNAN/HMX melt-cast explosive

The mechanical response and damage process of melt-cast explosives under complex stress states can be affected by having a high-volume ratio of the energetic filler material to the matrix. Understanding the characteristics of the nonlinear mechanical properties of 2,4-dinitroanisole/cyclotetramethylenetetranitramine (DNAN/HMX) melt-cast explosives with a high solid-phase content can enable the analysis of the response mechanism of different strain rates. DNAN/HMX melt-cast explosives were investigated using a universal material testing machine and a split-Hopkinson pressure bar (SHPB). The stress equilibrium and constant-strain-rate loading of the low-impedance, low-strength DNAN/HMX melt-cast explosive material in the SHPB test were achieved using an incident wave shaping technique, and stress-strain curves were obtained at different strain rates (40, 51, 110, and 256 s-1). Based on the stress-strain relationship curve of DNAN/HMX melt-cast explosives, the viscoelastic parameters of the Visco-statistical cracking mechanism (SCRAM) constitutive model of DNAN/HMX melt-cast explosives are obtained by the least squares method. The results of quasi-static and dynamic loading show that the failure stress of DNAN/HMX melt-cast explosives gradually increases with the increasing strain rate, exhibiting a significant strain rate effect, while the dynamic loading displays the viscoelastic effect. The fitted Visco-SCRAM model can better predict the mechanical response of explosives under complex loading.