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The present study develops a crystal plasticity model for low-symmetric β-HMX octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine single crystals with only limited operative slip systems, accounting for nonlinear elasticity, volumetric coupled with deviatoric behavior, as well as thermo-dynamical consistency. Based on the decomposition of the stress tensor, the modified equation of state for anisotropic materials is adopted. Simulation results of the planar impact on β-HMX single crystals show good agreement with existing experimental data by Dick et al. (2004a) . In addition to providing new perspective to a range of orientation-dependent shock behaviors of β-HMX single crystal, the present work also discusses dislocation density, shear stress, strain localization, and anisotropic temperature increase in shocked β-HMX single crystals under shock loading. The proposed formulation and algorithms can also be applied to other low-symmetric crystals under impact or shock loading which gives irrecoverable deformation by crystallographic slip. Temperature calculations with various characteristic features for different orientations based on numerical simulations are explained, but no comparison with available experimental data is possible to our knowledge. Future studies should also examine phase change and twining as they also often occur in β-HMX single crystals.

In order to clarify the roles played by material constituents to the mechanical response of plastic-bonded explosives (PBXs), a micromechanical model is presented by combining a continuum damage model and a discrete damage model within the framework of a finite element code. Debonding of particle/matrix interface was modeled by the viscoelastic cohesive zones considering damage irreversibility which was representative of the effects of polymer binders in the composite system. Key damage and fracture process of PBX9501 explosive material under quasi-static uniaxial tension and compression were investigated. The simulated rate-dependent stress–strain curves for PBX9501 under compression agree well with experimental results given by Gray et al. (1998) [Gray III, G.T., Ida, D.J., Blumenthal, W.R., Cady, C.M., Peterson, P.D., 1998. High- and low-strain rate compression properties of several energetic material composites as a function of strain rate and temperature. In: Proceedings of the 11th Detonation Symposium. Snowmass Village, Colorado] which justifies the present model. The significant rate dependence of PBX explosive captured by the present model is mainly attributed to the cohesive law’s rate-dependence. Simulated Brazilian compression results show complicated interactions and larger relative movement among particles. Wavy fracture path tends to form in the aggregate model in Brazilian disc, while the cracking path is roughly vertical to loading direction in uniaxial tension specimen.