Modeling of the deformation and damage of plastic-bonded explosive in consideration of pressure and strain rate effects

The present study deals with numerical modeling of strain rate- and pressure-related deformation and damage of plastic-bonded explosives (PBXs). A mechanical constitutive model that combines a porosity model and a recently developed viscoelastic–viscoplastic damage model (Liu et al., 2019) [1] with necessary modifications is presented. The model is calibrated for 1,3,5-triamino-2,4,6-trinitrobenzene-based PBX by using available experimental data under hydrostatic cyclic compression, uniaxial compression at various strain rates, and triaxial compression with hydrostatic confining pressure. The complex behaviors of PBXs, such as irreversible volumetric compaction and coupled effects of strain rate and pressure on mechanical strength and failure mechanism, are investigated through several single-element tests at typical loading conditions and split Hopkinson pressure bar (SHPB) tests with lateral confinement. The model properly captures these behaviors and is able to accurately restitute the loading and reloading process of the confined SHPB test.