斜波压缩下HMX晶体的弹塑性行为

Elastic-plastic transition behaviors of HMX crystal under ramp wave compression

开展了(010)、(011)晶向HMX晶体的斜波压缩实验,获得了约15 GPa压力下的速度响应剖面。实验结果表明,HMX单晶存在明显弹塑性转变行为,且速度波形有下降趋势,这是材料的黏性效应导致,材料的弹性极限随着样品厚度增加而变化,不同晶向的材料动力学特性存在差异。结合Hobenemser-Prager黏弹塑性本构关系和三阶Birch-Murnaghan物态方程开展了HMX晶体斜波压缩物理过程的数值模拟,计算结果可以很好地描述HMX晶体的弹塑性转变这一物理过程。

The dynamics of HMX single crystals under ramp wave loading was studied experimentally and numerically.The ramp wave compression experiments of(010)and(011)crystal oriented HMX crystals within 15 GPa were carried out with the magnetic driven device CQ-4,which can provide a loading pressure with a rising time of 450-600 ns.The velocity curves of the interface between the HMX single crystal and the LiF single crystal were obtained with dual laser heterodyne velocimetry(DLHV).The experimental results show that there is an obvious elastic-plastic transition behavior in the loading section.The velocity waveforms have a downward trend in the elastic-plastic transition section,which is caused by the viscous effect of the HMX single crystal.The elastic limit of the HMX single crystal changes with the increase of the sample thickness.The Lagrange sound speed-particle velocity data and pressure-specific volume curves of(010)and(011)crystal oriented HMX crystals were obtained with the iterative Lagrange data processing method for dynamic impedance mismatch.The Lagrange sound speed-particle velocity relationships in the different crystal directions are different.The pressure-specific volume curve is close to isentropic experimental data by Sandia laboratory.The numerical simulation of the physical process of ramp wave compression of the HMX crystal was carried out with the viscoelastic plastic constitutive relation of Hobnemser-Prager and the third-order Birch-Murnaghan equation of state.The calculation results can well describe the physical process of the elasticplastic transformation of HMX crystal.