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

Abstract

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.

An Anisotropic Elastoviscoplasticity Model of Thermomechanical Responses of Shocked β‐HMX and α‐RDX Single Crystals

“…Based on the classical plasticity theory where the dislocation motion induced plastic volume change is usually assumed to be zero, the last terms of Eqs. (13), (14), (20) and (21) are set to zero. Moreover, heat transfer and in-ternal energy source are not included, therefore Eq.…”

“…We have performed a series of plate impact experiments on orientated β-HMX and α-RDX single crystals to obtain anisotropic dynamic behavior and to investigate the deformation mechanisms as given in Table 1 and Table 2 [13]. Figure 2 (a) shows the schematic diagram of the experiment configuration.…”

“…Previous experimental works on oriented βcyclotetramethylene tetranitramine (β-HMX) and αcyclotrimethylene trinitramine (α-RDX) single crystals by researchers from Los Alamos National Laboratory greatly advances the understandings and development of constitutive models of explosive single crystals. According to plate impact tests on oriented HMX single crystals [12], oriented RDX single crystals [12], and our recent work on oriented HMX and RDX single crystal [13], the anisotropic mechanical response exhibit obvious anisotropy which has been connected with their intrinsic ignition sensitivity. Coffey and coworkers [14] observed that the presence of anisotropic lattice and molecular distortions in explosive crystals tended to undergo orientation-dependent, plastic deformation under loading.…”

“…β-HMX single crystals plate impact experiments[13]. α-RDX single crystals plate impact experiments[13].…”