Dynamic Anisotropic Response of β-HMX and α-RDX Single Crystals Using Plate Impact Experiments at ∼1 GPa

Dynamic responses of several orientations of cyclotetramethylene tetranitramine (HMX) and cyclotrimethylene trinitramine (RDX) single crystals were investigated by using plate impact experiments. The orientations studied included (011), (010), (100), (−111), (01−1), and (11−1) planes of HMX single crystals and (210), (100), (11−1), (2−10), and (111) planes of RDX single crystals. Crystal/window interface particle velocity profiles, which were measured by using velocity interferometer system for any reflector, showed distinct elastic-plastic double-wave structures. Dynamic mechanical properties were obtained according to impedance matching method. Elastic-plastic responses of HMX and RDX exhibited strong anisotropy, nonlinear elasticity, and pressure/strain-rate dependency. Anisotropy was explained by analyzing the relationship between the impact plane and deformation systems. Results revealed insights into ignition mechanisms and impact sensitivity and provided multiple data for calibration of physical-based constitutive models.